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Cobaltocenium-containing (co)polysiloxanes (Cc-PDMSs) with terminal and side groups were synthesized by the reaction of catalyst-free hydroamination between ethynylcobaltocenium hexafluorophosphate and polysiloxanes comprising amino moieties as terminal and side groups. The conversion of NH2 groups in the polymers reaches 85%. The obtained (co)polysiloxanes "gelate" due to an increase in their molecular weight by approx. 30 times, when stored at room temperature over one week. "Gelated" Cc-PDMSs remain soluble in most polar solvents. The structure of Cc-PDMSs and the mechanism of "gelation" were established by 1H, 13C{1H}, 29Si{1H}, 19F{1H}, 31P{1H} nuclear magnetic resonance, infrared, ultraviolet–visible, and X-ray photoelectron spectroscopies. As determined by cyclic voltammetry, Cc-PDMSs possess redox properties (CoII/CoIII transitions at E1/2 = −1.8 and −1.3 V before and after "gelation", respectively). This synthetic approach allows to increase the molecular weights of the synthesized polysiloxanes functionalized with cobaltocenium groups easily, leading to their higher film-forming ability, which is desirable for some electronic applications. Cc-PDMSs can be utilized as redox-active polymer films in modified electrodes, electrochromic devices, redox-active coatings, and components for batteries. [ABSTRACT FROM AUTHOR]

The synthesis and isolation of [Ru(Cp)(PCy2NPh2)(=C=CHPh]PF6 and [Ru(Cp*)(PCy2NCy2)(=C=CHPh)]PF6 was successfully accomplished. Use of these ruthenium vinylidene complexes for stoichiometric reactions with a variety of amines was performed. Upon reaction with alkyl amines, deprotonation of the Cβ hydrogen resulted in formation of acetylide complex [Ru(Cp*)(PCy2NPh2)(−C≡CPh)], and the species was confirmed through independent synthesis. In contrast, reaction of the less basic aryl amine aniline with [Ru(Cp)(PCy2NCy2)(=C=CHPh)]PF6 resulted in outer sphere addition to give a Fischer carbene product. [ABSTRACT FROM AUTHOR]

The synthesis of carbon–heteroatom bonds, a crucial element in organic chemistry, often requires obstacles in direct amine integration with olefins. This study introduces a sustainable approach for producing nitrogen-bearing molecules through the Markovnikov hydroamination of vinylarenes with carboxamides, employing Hβ zeolite as an effective heterogeneous catalyst in a solvent-free environment. We explored the method's adaptability over various substrates, achieving consistently high yields and regioselectivity in the resultant products. The procedure's scalability to gram-level production and the catalyst's sustainable reuse for multiple cycles (up to five) underscores its viability for industrial application, indicating a significant increase in organic synthesis activity. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: The synthesis of N‐glycosides has received significant attention due to their crucial role in carbohydrate chemistry. Despite considerable advancements developed in the construction of N‐glycosides, methods for the stereoselective construction of 2‐deoxy‐α‐N‐glycosides are still limited. Herein, we disclosed a nickel‐catalyzed hydroamination of glycals under mild conditions. This transformation could allow for the stereoselective synthesis of an array of 2‐deoxy‐α‐N‐glycosides with excellent α‐stereoselectivity. Nickel‐catalyzed glycosylation reactions, particularly those involving anomeric C(sp3)‐metal bond formation, have proven to be an effective and stereoselective strategy for producing various N‐glycosides. Additionally, with highlight of the application of this reaction, γ‐sugar amino acid derivatives were synthesized. [ABSTRACT FROM AUTHOR]

We described a copper(I)‐catalyzed atom economic and selective hydroamination‐cyclization of alkynyl‐tethered quinazolinones to prepare a variety of indole‐fused pyrazino[1,2‐a]quinazolinones in good to excellent yields ranging from 39 %–99 % under mild reaction conditions. Control experiments revealed that coordination‐directed method of quinazolinone moiety with copper(I) was important for the selective hydroamination‐cyclization of alkynes at the N1‐atom instead of N3‐atom of quinazolinone. The reaction could be easily performed at gram scales and some prepared indole‐fused pyrazino[1,2‐a]quinazolinones with donating groups on the indole moiety showed a distinct fluorescence emission wavelength with blue shift under the acid conditions. [ABSTRACT FROM AUTHOR]

Ylide‐functionalized phosphines (YPhos) have been shown to yield highly active gold catalysts owing to their high donor capacity. To examine the impact of ylide functionalization on a given ligand structure, a series of ferrocenyl diphosphines functionalized with no, one or two ylide moieties and their corresponding bimetallic gold complexes were prepared. The complexes feature an anti‐conformation of the two phosphine moieties, guaranteeing the presence of two independent metal centers. Comparative studies of the complexes in the hydroamination and hydrohydrazination of alkynes revealed a significant increase in catalytic activity for each newly introduced ylide group. The di‐YPhos ligands were revealed to be the most active precatalysts, functioning effectively even at 0.1 or 0.2 mol % catalyst loading. This catalytic efficiency was demonstrated for a series of alkynes, amines and hydrazines. [ABSTRACT FROM AUTHOR]

Catalytic olefin hydroamination reactions are some of the most atom‐economical transformations that bridge readily available starting materials–olefins and high‐value‐added amines. Despite significant advances in this field over the last two decades, the formal hydroamination of nonactivated aromatic compounds remains an unsolved challenge. Herein, we report the extension of olefin hydroamination to aromatic π‐systems by using arenophile‐mediated dearomatization and Cu‐catalysis to perform 1,2‐hydroamination on nonactivated arenes. This strategy was applied to a variety of substituted arenes and heteroarenes to provide general access to structurally complex amines. We conducted DFT calculations to inform mechanistic understanding and rationalize unexpected selectivity trends. Furthermore, we developed a practical, scalable desymmetrization to deliver enantioenriched dearomatized products and enable downstream synthetic applications. We ultimately used this dearomative strategy to efficiently synthesize a collection of densely functionalized small molecules. [ABSTRACT FROM AUTHOR]

An efficient and highly selective reaction of 2‐(2‐bromophenyl)‐5,6,7,8‐tetrahydrobenzo [4,5] thieno[2,3‐d]pyrimidin‐4(3H)‐one and terminal alkyne has been developed under palladium‐free conditions by CuI‐catalyzed sequential Sonogashira coupling reaction and 5‐exo‐dig hydroamination reaction. A series of 11‐arylidene‐2,3,4,11‐tetrahydrobenzo [4′,5′]thieno [2′,3′ : 4,5]pyrimido [2,1‐a]isoindol‐13(1H)‐one derivatives with only the (E)‐configuration were obtained. [ABSTRACT FROM AUTHOR]

Nitrogen-containing compounds, such as amines, hydrazines, and heterocycles, play an indispensable role in medicine, agriculture, and materials. Alkylated derivatives of these compounds, especially in sterically congested environments, remain a challenge to prepare. Here we report a versatile method for the regioselective hydroamination of readily available unactivated olefins with diazirines. Over fifty examples are reported, including the protecting group-free amination of fourteen different natural products. A broad functional group tolerance includes alcohols, ketones, aldehydes, and epoxides. The proximate products of these reactions are diaziridines, which, under mild conditions, are converted to primary amines, hydrazines, and heterocycles. Five target- and diversity-oriented syntheses of pharmaceutical compounds are shown, along with the preparation of a bis-15N diazirine validated in the late-stage isotopic labeling of an RNA splicing modulator candidate. In this work, we report using diazirine (1) as an electrophilic nitrogen source in a regioselective hydroamination reaction, and the diversification of the resulting diaziridines. Nitrogen-containing compounds play an indispensable role in medicine, agriculture and materials, but alkylated derivatives especially in sterically congested environments, remain a challenge to prepare. Here, the authors report a versatile method for the regioselective hydroamination of readily available unactivated olefins with diazirines. [ABSTRACT FROM AUTHOR]

Bis(sulfoximine) yttrium complexes as catalysts for enantioselective intramolecular hydroaminations were prepared for the first time and characterized by a multinuclear NMR study including the nuclei 1H, 13C, 15N and 89Y. The stoichiometries of the complexes were confirmed by a Job plot. In addition to the experimental results, the 89Y NMR shifts and the complex structures were elucidated by DFT calculations. [ABSTRACT FROM AUTHOR]

Acyclic diaminocarbenes (ADCs)–Metal complex having strong donor ability and thermal stability led to extensive usability across every area of inorganic and organometallic chemistry. The unique properties of acyclic diaminocarbenes (ADCs) provide certain advantages over other carbene ligands and have the potential to make a great impact in catalysis. Further, the straightforward synthesis of M–ADCs (metal bound acyclic diaminocarbenes) complexes via metal-mediated reaction provides a wide range of well-defined metal carbene catalysts, which might inspire more researchers to devise unsymmetrically substituted, chiral, and novel acyclic carbene compounds. Although the above synthetic route is limited to a few late transition metals, but have great opportunities to expand the scope of this method. The application of M–ADCs complexes as a catalyst for several organic transformation reactions such as various cross-coupling reactions and asymmetric synthesis like hydroarylation, hydroazidation, hydroamination, cyclization and addition reactions which have shown comparable or even higher activities than the analogous M–NHCs based on all the reports presented. Recent findings of donor ability of several ADC ligands would be useful in fine-tuning the electronic properties, and then a catalyst with a certain combination of donicity and steric requirement could open new doors in catalytic reactivity. Thus, the objective of this review is to assess the recent growths that have been made in designing novel and chiral ADCs ligands and synthesizing ADCs–Metal complexes and to highlight catalytic activities of metal acyclic diaminocarbene complexes for cross-coupling reactions. [ABSTRACT FROM AUTHOR]

Abstract In the growing field of peptidomimetics, there is a constant need for new synthetic methods to generate new bioactive compounds. Herein, we present an atom‐economic approach for the branched‐selective allylation of aliphatic amine moieties of α‐amino acids and small oligopeptides. This Rh‐catalyzed hydroamination of allenes with a commercially available ligand forms a new stereocenter, often chemoselectively, in a catalyst‐controlled manner, providing high yields and stereoselectivities without the need for an additive. The method is shown to be effective in gram scale without the need for column chromatography for purification, and ready‐to‐use allylated substrates for solid‐phase peptide synthesis can be synthesized in two steps from the products of the catalysis.

β‐fluorocarbanions have garnered considerable attention for their dual reactivity in nucleophilic processes and β‐fluorine elimination. In this study, a thorough computational analysis was conducted to explore the reactions of α‐(trifluoromethyl)styrenes with 2‐pyridones to delineate the factors determining protonation or defluorination pathways for the in situ generated β‐fluorocarbanions under varied basic conditions. Our findings illuminate the critical role of organobase basicity in steering the direction of the competitive protonation and β‐fluorine elimination reactions. We propose the use of pKaH values of organobases as a quantitative indicator for discerning the predominant reaction pathways. This provides an efficient approach to predict and control the reaction outcome, facilitating the deliberate design of reactions to leverage the unique reactivity of β‐fluorocarbanions in the realm of fluorine chemistry. [ABSTRACT FROM AUTHOR]

Exclusive C-donating ligands are rarely used with kinetically labile heavier alkaline earths (Ca, Sr, Ba). We report herein the aptitude of a combination of NHC with fluorenyl connected by a flexible –(CH2)2– linker as a ligand support for heteroleptic Ca– and Sr–N(SiMe3)2 and iodides. The Ca–N(SiMe3)2 complex even catalyzes the intramolecular hydroamination of aminoalkenes to showcase the effectiveness of this ligand framework. [ABSTRACT FROM AUTHOR]

The intermolecular hydroamination of norbornene with simple amines was achieved using silyl‐substituted ortho‐terphenoxide yttrium complexes. Excellent conversion was obtained for both benzylic and aliphatic amines. For benzyl and linear aliphatic amines, the highest activity was observed for the sterically more encumbered methyldiphenylsilyl‐substituted complex, whereas the trimethylsilyl‐substituted complex was more active for sterically encumbered primary amines. [ABSTRACT FROM AUTHOR]

Enantiomerically enriched crown ethers (CE) exhibit strong asymmetric induction in phase transfer catalysis, supramolecular catalysis and molecular recognition processes. Traditional methods have often been used to access these valuable compounds, which limit their diversity and consequently their applicability. Herein, a practical catalytic method is described for the gram scale synthesis of a class of chiral CEs (aza‐crown ethers; ACEs) using Rh‐catalyzed hydroamination of bis(allenes) with diamines. Using this approach, a wide range of chiral vinyl functionalized CEs with ring sizes ranging from 12 to 36 have been successfully prepared in high yields of up to 92 %, dr of up to >20 : 1 and er of up to >99 : 1. These vinyl substituted CEs allow for further diversification giving facile access to various CE derivatives as well as to their three‐dimensional analogues using ring‐closing metathesis. Some of these chiral CEs themselves display high potential for use in asymmetric catalysis. [ABSTRACT FROM AUTHOR]

An exclusive anti‐Markovnikov hydroamination as well as hydroalkoxylation of allylic alcohols catalyzed by a simple catalyst Y(CH2SiMe3)3(THF)2 has been developed, providing a variety of γ‐amino and γ‐alkoxy alcohols in good yields under mild conditions. Moreover, this protocol is applied to the synthesis of drug molecules Propipocaine and Proroxan. The rare‐earth metal catalyst features readily available, wide substrate compatability, exclusive anti‐Markovnikov selectivity, and performs in the absence of a base or an additive. [ABSTRACT FROM AUTHOR]

We have previously reported the first formal hydroamination of enamines for the synthesis of chiral 1,2‐diamines. Here, we describe: (i) the discovery, optimization, and substrate expansion of this reaction; (ii) a novel and straightforward protocol for the "click‐type" synthesis of enamines in quantitative yield utilizing sodium sulfate in a dual role as an ancillary and dehydrating agent without the need for workup or purification; (iii) the application of this methodology to the first enantioselective synthesis of orthogonally protected 1,1′‐(1‐(4‐fluorophenyl)ethane‐1,2‐diyl) piperazines, a scaffold for rapid lead optimization in drug discovery; (iv) a computational investigation into the mechanism and rationalization of the enantioselectivities of the reaction. [ABSTRACT FROM AUTHOR]

Synthetic access to a variety of aliphatic and vinylic pentafluorosulfanylated building blocks remains a major challenge in contemporary organofluorine chemistry hampering its investigation in the context of medicinal chemistry, agrochemistry and functional materials. Herein, we report a bench‐top protocol to access the virtually unknown class of α‐SF5‐enamines under mild reaction conditions in good to excellent yields (up to 95 %). This reaction combines the protodesilylation of the commercially available precursor TASP with the in situ hydroamination of HC≡C−SF5. The on‐site use of highly toxic gases or corrosive reagents is avoided, making access to this motif applicable to a wide chemical audience. The excellent E‐diastereoselectivity of this two‐step cascade reaction is suggested to be the result of the convergence of the fast Z‐/E‐ isomerization of a vinyl anion as well as the isomerization of the iminium ion. The remarkable thermal stability of these SF5‐enamines encourages further studies of their synthetic utility. [ABSTRACT FROM AUTHOR]

N-heterocyclic carbene (NHC) silver(I) and gold(I) complexes have found different applications in various research fields, as in medicinal chemistry for their antiproliferative, anticancer, and antibacterial activity, and in chemistry as innovative and effective catalysts. The possibility of modulating the physicochemical properties, by acting on their ligands and substituents, makes them versatile tools for the development of novel metal-based compounds, mostly as anticancer compounds. As it is known, chemotherapy is commonly adopted for the clinical treatment of different cancers, even though its efficacy is hampered by several factors. Thus, the development of more effective and less toxic drugs is still an urgent need. Herein, we reported the synthesis and characterization of new silver(I) and gold(I) complexes stabilized by caffeine-derived NHC ligands, together with their biological and catalytic activities. Our data highlight the interesting properties of this series as effective catalysts in A3-coupling and hydroamination reactions and as promising anticancer, anti-inflammatory, and antioxidant agents. The ability of these complexes in regulating different pathological aspects, and often co-promoting causes, of cancer makes them ideal leads to be further structurally functionalized and investigated. [ABSTRACT FROM AUTHOR]

Electrochemically generated amidyl radical species produced distinct inter- or intramolecular hydroamination reaction products via a proton-coupled electron transfer (PCET) mechanism. Cyclic voltammetry (CV) analysis indicated that the chemoselectivity was derived from the size of the hydrogen bond complex, which consisted of the carbamate substrate and phosphate base, and could be controlled using 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP) as an additive. These results provide fundamental insights for the design of PCET-based redox reaction systems under electrochemical conditions.

Cobaltocenium-containing (co)polysiloxanes (Cc-PDMSs) with terminal and side groups were synthesized by the reaction of catalyst-free hydroamination between ethynylcobaltocenium hexafluorophosphate and polysiloxanes comprising amino moieties as terminal and side groups. The conversion of NH2 groups in the polymers reaches 85%. The obtained (co)polysiloxanes “gelate” due to an increase in their molecular weight by approx. 30 times, when stored at room temperature over one week. “Gelated” Cc-PDMSs remain soluble in most polar solvents. The structure of Cc-PDMSs and the mechanism of “gelation” were established by 1H, 13C{1H}, 29Si{1H}, 19F{1H}, 31P{1H} nuclear magnetic resonance, infrared, ultraviolet–visible, and X-ray photoelectron spectroscopies. As determined by cyclic voltammetry, Cc-PDMSs possess redox properties (CoII/CoIII transitions at E1/2 = −1.8 and −1.3 V before and after “gelation”, respectively). This synthetic approach allows to increase the molecular weights of the synthesized polysiloxanes functionalized with cobaltocenium groups easily, leading to their higher film-forming ability, which is desirable for some electronic applications. Cc-PDMSs can be utilized as redox-active polymer films in modified electrodes, electrochromic devices, redox-active coatings, and components for batteries.

The complexation behavior of 3,3'‐silyl‐substituted ortho‐terphenoxide ligands o‐C6H4(C6H2‐2‐OH‐3‐SiR3‐5‐Me)2 (SiR3= SiPh3, SiMePh2, SiMe3, Sit‐BuMe2) with a range of yttrium, titanium, niobium and tantalum precursors was examined. The complexation of the ligands with [Y(N(SiHMe2)2)3(THF)2] yielded monomeric complexes, as confirmed by NMR spectroscopy and X‐ray crystallography for the methyldiphenylsilyl‐ and tert‐butyldimethylsilyl‐substituted complex. The triphenylsilyl‐substituted yttrium bis(dimethylsilyl)amido complex showed good activity in the intramolecular hydroamination reaction of aminoalkenes. Complexation with Ti(NMe2)4 yielded a mixture of products, depending on the silyl substituents and the solvent used for complexation. A mono‐ligated bimetallic titanium complex and a bisligated titanium complex were analyzed by X‐ray crystallography. Complexation with M(NMe2)5 (M=Nb, Ta) produced the corresponding monomeric ortho‐terphenoxide complexes as confirmed by NMR spectroscopy and X‐ray structure analysis of a niobium complex and 3 tantalum complexes. [ABSTRACT FROM AUTHOR]

An Ir-catalysed regioselective hydroamination of internal homoallylic amines is reported. Both cyclic and acyclic internal olefins undergo directed hydroamination reactions with both aromatic and cyclic aliphatic amines to afford a variety of 1,4-diamines in fair to excellent yields. Diastereoselectivity and mechanistic investigations support that for cyclic substrates the reactions are proceeding via trans-aminoiridation to form a 5-membered metalacyclic intermediate. [ABSTRACT FROM AUTHOR]

Nitrogen‐centered radicals (NCRs) have been widely recognized as versatile synthetic intermediates for the construction of nitrogen containing molecules of high value. As such, there has been a long‐standing interest in the field of organic synthesis to develop novel nitrogen‐based radicals and explore their inherent reactivity. In this study, we present the generation of aromatic N‐heterocyclic radicals and their application in a novel and diverse functionalization of unactivated alkenes. Bench‐stable aromatic N‐heterocyclic pyridinium salts were employed as crucial NCR precursors, which enabled the efficient conversion of various unactivated alkenes into medicinally relevant alkylated N‐heterocyclic amines. This approach offers an unexplored retrosynthetic disconnection for the synthesis of related molecules that commonly possess therapeutic value. Furthermore, this platform can be extended to the synthesis of densely functionalized heterocyclic amines by utilizing disulfides and diethyl bromomalonate as radical quenchers. Mechanistic investigations indicate an energy transfer (EnT) pathway involving the formation of a transient aromatic N‐heterocyclic radical, radical addition to unactivated alkenes, and subsequent generation of the amination product through either hydrogen atom transfer (HAT) or radical addition processes. [ABSTRACT FROM AUTHOR]

Imines are valuable key compounds for synthesizing several nitrogen-containing molecules used in biological and industrial fields. They have been obtained, as highly regioselective Markovnikov products, by reacting several alkynes with arylamines in the presence of three new N-Heterocyclic carbene gold(I) complexes (3b, 4b, and 6b) together with the known 1-2b and 7b gold complexes as well as silver complexes 1-2a. Gold(I) complexes were investigated by means of NMR, mass spectroscopy, elemental analysis, and X-ray crystallographic studies. Accurate screening of co-catalysts and solvents led to identifying the best reaction conditions and the most active catalyst (2b) in the model hydroamination of phenylacetylene with aniline. Complex 2b was then tested in the hydroamination of alkynes with a wide variety of arylamines yielding a lower percentage of product when arylamines with both electron-withdrawing and electron-donating substituents were involved. Computational studies on the rate-determining step of hydroamination were conducted to shed light on the significantly different yields observed when reacting arylamines with different substituents. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: Here, we report a cobalt‐catalyzed sequential dehydrogenative Heck silylation/hydroamination of styrenes with hydrosilane and diazo compound to access 1‐amino‐2‐silyl compounds with excellent regioselectivity. This difunctionalization reaction could undergo smoothly using 1 mol% catalyst loading with good functional group tolerance. Not only di‐ and tri‐substituted hydrosilanes, but also alkoxysilane is suitable, which does explore the scope of the family of 1‐amino‐2‐silyl compounds. The ligand relay phenomenon between neutral tridentate NNN ligand and anionic NNN ligand is observed for the first time via absorption spectral analysis in this one‐pot, two‐step transformations. The primary mechanism has been proposed based on the control experiments. [ABSTRACT FROM AUTHOR]

[(Bn2Cyclam)Y(N(SiMe3)2)] was prepared by reaction of H2Bn2Cyclam with Y[N(SiMe3)2]3. The protonation of the macrocycle ligand in [(Bn2Cyclam)Y(N(SiMe3)2)] is observed upon reaction with [HNMe3][BPh4] leading to the formation of [(HBn2Cyclam)Y(N(SiMe3)2)][BPh4]. DFT analysis of [(Bn2Cyclam)Y(N(SiMe3)2)] showed that the HOMO is located on the anionic nitrogen atoms of the cyclam ring indicating that protonation follows orbital control. Addition of H2Bn2Cyclam and H2(3,5-tBu2Bn)2Cyclam to a 1:3 mixture of YCl3 and LiCH2SiMe3 in THF resulted in the formation of [((C6H4CH2)BnCyclam)Y(THF)(µ-Cl)Li(THF)2] and [Y{(η3-3,5-tBu2Bn)2Cyclam}Li(THF)], respectively. The reaction of H23,5-tBu2Bn2Cyclam with Y(CH2SiMe3)3(THF)2 was studied and monitored by a temperature variation NMR experiment revealing the formation of [(3,5-tBu2Bn2Cyclam)Y(CH2SiMe3)]. Preliminary catalytic assays have shown that [Y{(η3-3,5-tBu2Bn)2Cyclam}Li(THF)] is a very efficient catalyst for the intramolecular hydroamination of 2,2-diphenyl-pent-4-enylamine. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: Here, we report a cobalt‐catalyzed sequential dehydrogenative Heck silylation/hydroamination of styrenes with hydrosilane and diazo compound to access 1‐amino‐2‐silyl compounds with excellent regioselectivity. This difunctionalization reaction could undergo smoothly using 1 mol% catalyst loading with good functional group tolerance. Not only di‐ and tri‐substituted hydrosilanes, but also alkoxysilane is suitable, which does explore the scope of the family of 1‐amino‐2‐silyl compounds. The ligand relay phenomenon between neutral tridentate NNN ligand and anionic NNN ligand is observed for the first time via absorption spectral analysis in this one‐pot, two‐step transformations. The primary mechanism has been proposed based on the control experiments. [ABSTRACT FROM AUTHOR]

The intermolecular anti‐Markovnikov hydroamination of vinylsilanes was achieved utilizing five silyl‐substituted ortho‐terphenoxide yttrium complexes. The highest activity was observed for the most sterically encumbered triphenylsilyl‐substituted complex. Excellent activity and complete anti‐Markonikov selectivity were obtained for a variety of benzylic and aliphatic primary and secondary amines. Interestingly, the reaction with 2‐picolylamine produced the hydroaminoalkylation product rather than the hydroamination product. Reaction of dimethyldivinylsilane resulted in a range of 1,4‐azasilinanes via sequential hydroamination/endocyclization in good yields. [ABSTRACT FROM AUTHOR]

We report the first enantioselective addition of pyrazoles to 1,3-dienes. Secondary and tertiary allylic pyrazoles can be generated with excellent regioselectivity. Mechanistic studies support a pathway distinct from previous hydroaminations: a Pd0 -catalyzed ligand-to-ligand hydrogen transfer (LLHT). This hydroamination tolerates a range of functional groups and advances the field of diene hydrofunctionalization.

Imines are valuable key compounds for synthesizing several nitrogen-containing molecules used in biological and industrial fields. They have been obtained, as highly regioselective Markovnikov products, by reacting several alkynes with arylamines in the presence of three new N-Heterocyclic carbene gold(I) complexes (3b, 4b, and 6b) together with the known 1-2b and 7b gold complexes as well as silver complexes 1-2a. Gold(I) complexes were investigated by means of NMR, mass spectroscopy, elemental analysis, and X-ray crystallographic studies. Accurate screening of co-catalysts and solvents led to identifying the best reaction conditions and the most active catalyst (2b) in the model hydroamination of phenylacetylene with aniline. Complex 2b was then tested in the hydroamination of alkynes with a wide variety of arylamines yielding a lower percentage of product when arylamines with both electron-withdrawing and electron-donating substituents were involved. Computational studies on the rate-determining step of hydroamination were conducted to shed light on the significantly different yields observed when reacting arylamines with different substituents.

A stereocontrolled degradable polymer was synthesized via living cascade enyne metathesis polymerization. Highly stereodefined N,O‐acetal‐containing enyne monomers were prepared using the Pd‐catalyzed hydroamination of alkoxyallenes and ring‐closing metathesis. The resulting chiral polymer exhibited a narrow dispersity window. Block copolymers were prepared not only by sequentially adding nondegradable and degradable monomers but also by using enantiomerically different monomers to produce stereocontrolled blocks. Owing to the hydrolyzable N,O‐acetal moiety in the backbone structure, the resulting polymer could degrade under acidic conditions generated using various acid concentrations to control the degradation. Additionally, the aza‐Diels–Alder reaction modified the polymer without losing the stereochemistry. [ABSTRACT FROM AUTHOR]

Sulfoximines, the isoelectronic with sulfones, represent a class of alternative and intriguing motifs in both discovery program and agrochemistry. N‐Alkylation on imines could significantly improve their bioactivities, but the lack of general method has hindered their further uptake by medicinal chemistry and drug development. Herein, we present a mild photocatalytic anti‐Markovnikov hydroamination of alkenes to construct N‐alkylated sulfoximines with broad substrate tolerance on primary, secondary and tertiary alkyl substituents as well as a diverse range of sulfoximines. The mechanistic studies support the photocatalytic pathway, and demonstrate that the alkene radical cation rather than the iminium radical serves as the key intermediate in the transformation. [ABSTRACT FROM AUTHOR]

The excellent catalytic performances of enzymes in terms of activity and selectivity are an inspiration for synthetic chemists and this has resulted in the development of synthetic containers for supramolecular catalysis. In such containers the local environment and pre‐organization of catalysts and substrates leads to control of the activity and selectivity of the catalyst. Herein we report a supramolecular strategy to encapsulate single catalysts in a urea‐functionalized Fe4L6 cage, which can co‐encapsulate a functionalized urea substrate through hydrogen bonding. Distinguished selectivity is obtained, imposed by the cage as site isolation only allows catalysis through π activation of the substrate and as a result the selectivity is independent of catalyst concentration. The encapsulated catalyst is more active than the free analogue, an effect that can be ascribed to transitionstate stabilization rather than substrate pre‐organization, as revealed by the MM kinetic data. The simple strategy reported here is expected to be of general use in many reactions, for which the catalyst can be functionalized with a sulfonate group required for encapsulation. [ABSTRACT FROM AUTHOR]

An effective and novel heterogeneous beta zeolite supported CuO (Cuβ) catalyzed double hydroamination of alkynes for the synthesis of 2,3‐dihydroquinazolin‐4(1H)‐ones has been achieved in a solvent‐free condition. Cuβ zeolite was synthesized by impregnation method. The synthesized Cuβ was characterized by X‐ray diffraction, Fourier transformation infrared spectroscopy, transmission electron microscopy, scanning electron microscopy, and X‐ray photoelectron spectroscopy. Pure Hβ (18 % yield) or Nano CuO (44 % yield) displayed poor catalytic activity, whereas 1 % Cuβ (96 % yield) showed higher catalytic activity for double hydroamination of alkynes due to the synergistic effect of CuO and Hβ zeolite in the reaction. The new protocol offers an appealing approach to a number of di‐substituted quinazolinones with decent to excellent yields. The catalyst has been successfully recycled for up to 5 consecutive cycles. [ABSTRACT FROM AUTHOR]

Chiral 1,2‐diamines are privileged scaffolds among bioactive natural products, active pharmaceutical ingredients, ligands for transition‐metal‐based asymmetric catalysis and organocatalysts. Despite this interest, the construction of chiral 1,2‐diamine motifs still remains a challenge. To address this, an iridium(III)‐catalyzed intermolecular C(sp3)‐H amidation reaction was developed. This method relies on the design of a new, cheap and cleavable exo‐protecting/directing group derived from camphorsulfonic acid, which is directly installed from easily accessible precursors, and furnishes scalemic free 1,2‐diamines upon cleavage of both nitrogen substituents. It was found applicable to both α‐secondary and α‐tertiary‐1,2‐diamines, for which a two‐step protocol involving intermolecular olefin hydroamination and C(sp3)‐H amidation was developed. Kinetic and computational studies provided insights into the observed reactivity difference between pairs of diastereoisomeric substrates. [ABSTRACT FROM AUTHOR]

As part of our efforts to interface late transition metals with Lewis acidic main group fragments, we have decided to investigate gold complexes bearing halogermanes as Z‐type ligands. Toward this end, we have synthesized complexes of general formula [(o‐(Ph2P)C6H4)2(Ph)(X)GeAuCl] (X = F, Cl). Experimental and computational analyses indicate the presence of an Au→Ge interaction in both cases. Chloride abstraction reactions have also been investigated. In the case of X = Cl, double chloride abstraction with AgSbF6 affords a putative dication that gradually abstracts fluoride from its counterion. This putative dication is also significantly more active as a catalyst than its monocationic analog in alkyne hydroamination reactions. [ABSTRACT FROM AUTHOR]

Stereodivergent synthesis of 2,5-disubstituted pyrrolidines was achieved via a Au-catalyzed tandem intramolecular alkyne hydroamination/iminium formation/Et3SiH reduction. Importantly, the stereochemical outcome could be switched by choosing an appropriate nitrogen protecting group. Total synthesis of a diastereomeric pair of alkaloid natural products, monomorine I and indolizidine 195B, was achieved to showcase the synthetic utility of the tandem reaction. [ABSTRACT FROM AUTHOR]

This study reported an efficient two‐step method based on the sequential post‐Ugi hydroamination reaction for synthesizing a novel class of benzimidazole‐pyrazines with high yields. First, a Ugi fourcomponent reaction (Ugi‐4CR) is carried out using readily available starting materials, i. e. 1H‐benzo[d]imidazole‐2‐carboxylic acid, aldehydes, propargylamine, and isocyanides, in methanol at ambient temperature. Afterward, the Ugi products undergoes a sequential intramolecular hydroamination/cyclization reaction between a nitrogen of imidazole and alkyne functional group in aqua media in the presence of AuCl3 as a catalyst to obtain benzimidazole‐pyrazine products. These heterocyclic compounds may have a potential to be utilized in designing modern drugs with desirable features. [ABSTRACT FROM AUTHOR]

Alkyne hydroamination is an effective approach for the production of enamines and enamine‐containing N‐heterocycles. However, stereoselectivity control is a considerable challenge in this reaction because of the electronic repulsion between an incoming nitrogen lone pair and the alkyne π‐system. Herein, we propose a methodology involving β‐regio‐ and Z‐selective alkyne hydroamination by using tetrafluoro‐λ6‐sulfanyl (SF4) alkynes under superbasic, naked anion conditions. The reaction is compatible with a wide variety of N‐heterocycles, including indoles, carbazoles, pyrazoles, and imidazoles, and selectively furnishes SF4‐linked Z‐vinyl enamines with β‐regioselectively. Moreover, the method can be extended to the β‐ and Z‐controlled, base‐mediated alkyne hydrophenoxylation with phenols to provide SF4‐linked Z‐vinyl ethers in high yields. As the SF4 unit has attracted attention as a bioisostere for alkynes, p‐benzenes, bicyclo[1.1.1]pentyl (BCP) groups, and cubanes in medicinal chemistry, this chemistry represents an effective approach to creating novel drug candidates incorporating SF4‐containing molecules. [ABSTRACT FROM AUTHOR]

A gold-catalyzed protocol to obtain functionalized 3H-pyrrolo [1,2,3-de] quinoxalines from suitable substituted N-alkynyl indoles has been proposed. The mild reaction conditions were revealed to be compatible with different functional groups, including halogen, alkoxyl, cyano, ketone, and ester, allowing the isolation of title compounds with yields from good to high. A reaction mechanism has been proposed, and theoretical calculations have been provided to rationalize the final step of the hypothesized reaction mechanism. As quinoxaline-containing polycyclic compounds, this class of molecules may represent a valuable template in medicinal chemistry and material science. [ABSTRACT FROM AUTHOR]

[21][24] We wish to report herein our synthetic approach toward -hydroxyamino ketones, which involves the radical acylation of nitrone with 2-acylbenzothiazolene under organophotoredox catalysis (route C). Metal- and Additive-Free Synthesis of -Hydroxyamino Ketones Enabled by Organophotocatalyst Hydroxyamino ketone, hydroxylamine, nitrone, benzothiazoline, metal-free, organophotocatalyst Keywords: hydroxyamino ketone; hydroxylamine; nitrone; benzothiazoline; organophotocatalyst; metal-free EN hydroxyamino ketone hydroxylamine nitrone benzothiazoline organophotocatalyst metal-free 1391 1394 4 07/11/23 20230725 NES 230725 Graph Nitrogen-containing compounds are prevalent in organic compounds, and a range of novel catalytic approaches have been extensively explored. [Extracted from the article]

Herein, a general applicable method for the atom‐economic catalytic construction of a broad range of 1,2‐dialkylaminoethers is presented. By taking advantage of an elaborated protocol for the photocatalyzed anti‐Markovnikov selective hydroamination of nonactivated alkenes, a series of 1,2‐dialkylaminoethers was accessed by reacting readily available vinyl ethers with secondary alkyl amines. It was demonstrated that the reaction can be performed at low catalyst loadings while the commonly employed triisopropylbenzene thiol Hydrogen Atom Transfer (HAT)‐catalyst was replaced by an easier accessible mesityl thiol. Furthermore, the inexpensive and readily available diphenyl disulfide was proven as suitable HAT‐catalyst alternative for the efficient hydroamination of simple vinyl ethers. [ABSTRACT FROM AUTHOR]

Enantiomerically pure amines are crucial intermediates for a wide range of pharmaceuticals, natural products, and bioactive compounds. Asymmetric intermolecular hydroamination of alkenes is one of the most atom-economical methods for the synthesis of chiral amines. However, the direct stereoselective hydroamination of alkenes remains a significant challenge. Herein, we developed a novel fully biocatalytic system to enable the direct stereoselective hydroamination of aryl alkenes to produce chiral amines. The process involves sequential alkene asymmetric hydration catalyzed by a hydratase (HD), followed by in situ oxidation of alcohol into ketone by two enantiocomplementary alcohol dehydrogenases (ADHs), and finally, enantioselective transformation of ketone into enantiomerically pure amine by a ω-transaminase (TA). The addition of lactate dehydrogenase (LDH) facilitated the connection between alcohol oxidation and pyruvate reduction, making the cascade reaction redox self-sufficient and driving the process towards the desired target product. In vitro cascade biocatalysis for asymmetric hydroamination of 4-hydroxystyrenes 1a–f was first investigated by using the combined enzymes (HD/ADHs/LDH/TA) with trace amounts of NAD+ (0.05 mM) and pyridoxal-5′-phosphate (PLP) (0.1 mM), affording both enantiomers of amines 4a–f in 30–90% conversions and >99% ee. Furthermore, whole-cell-based cascade biocatalysis was achieved by using the constructed recombinant Escherichia coli cells co-expressing the five enzymes without additional NAD+ cofactor; (R)- and (S)-amines 4a–f could be obtained in 35–93% conversions and >99% ee. Finally, the preparative experiments were demonstrated by using the whole-cell biocatalyst E. coli (RFM-ERR-CB) and E. coli (RFC-ERR-CB) with substrate 1a, affording (S)-4a and (R)-4a in 54.8% and 59.2% yields and >99% ee. This research achievement provides a highly selective, highly atom-economical, green and sustainable method for synthesizing chiral amines from alkenes via formal alkene asymmetric hydroamination. [ABSTRACT FROM AUTHOR]

Kinetic resolution is a powerful strategy for the isolation of enantioenriched compounds from racemic mixtures, and the development of selective catalytic processes is an active area of research. Here, we present a nickel‐catalyzed kinetic resolution of racemic α‐substituted unconjugated carbonyl alkenes via the enantio‐, diastereo‐, and regioselective hydroamination. This protocol affords both chiral α‐substituted butenamides and syn‐β2,3‐amino acid derivatives with high enantiomeric purity (up to 99 % ee) and selectivity factor up to >684. The key to the excellent kinetic resolution efficiency is the distinctive architecture of the chiral nickel complex, which enables successful resolution and enantioselective C−N bond construction. Mechanistic investigations reveal that the unique structure of the chiral ligand facilitates a rapid migratory insertion step with one enantiomer. This strategy provides a practical and versatile approach to prepare a wide range of chiral compounds. [ABSTRACT FROM AUTHOR]

Post‐synthesis modification of polymers streamlines the synthesis of functionalized polymers, but is often incomplete due to the negative polymer effects. Developing efficient polymer reactions in artificial systems thus represents a long‐standing objective in the fields of polymer and material science. Here, we show unprecedented macrocycle‐metal‐complex‐catalyzed systems for efficient polymer reaction that result in 100 % transformation of the main chain functional groups presumably via a processive mode reaction. The complete polymer reactions were confirmed in not only intramolecular reaction (hydroamination) but also intermolecular reaction (hydrosilylation) by using Pd‐ and Pt‐macrocycle‐catalyzed systems. The most fascinating feature of the both reactions is that higher‐molecular‐weight polymers reach completion faster. Various studies suggested that the reactions occur in the catalyst cavity via the formation of a supramolecular complex between the macrocycle catalyst and polymer substrate like pseudorotaxane, which should be of characteristic of the efficient polymer reactions progressing in a processive mode. [ABSTRACT FROM AUTHOR]

Green and sustainable access to chiral and achiral gold-IBiox complexes is reported. The gold complexes were synthesized using a simple, air-tolerant, weak base protocol carried out in a green solvent. Their catalytic activity was examined in the hydroamination of alkynes. The steric protection afforded the gold center by these ligands was quantified using the %Vbur model and compared with the most commonly encountered NHCs. [ABSTRACT FROM AUTHOR]