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AbstractWe report herein the stereoselective synthesis of 3-sulfone sugars in good yields from glycals and sodium arylsulfinates. Various 3,4-O-carbonate glycals were sulfonylated directly by a range of benzene- and naphthalene-sulfinic acid sodium salts catalyzed by cobalt species, demonstrating a broad substrate scope. The mechanism of cobalt-catalyzed decarboxylative allylation from the bottom face of the sugar ring due to the steric effect from the C3 group of glycals was proposed. Moroever, cobalt catalysis tends to favor branched allylation, resulting in excellent regioselectivity. This synthetic strategy features the green sulfone source, good functional group tolerance, exclusive regioselectivity, and excellent stereoselectivity. [ABSTRACT FROM AUTHOR]

Bis(alkenyl)boronates react with optically active Ir(π‐allyl) species in a process that involves allylation of the more substituted olefin and 1,2‐metalate shift of the less substituted olefin. The method constructs valuable enantioenriched tertiary allylic boronic esters with high chemoselectivity, enantioselectivity and diastereoselectivity. Allylic functionalization reactions transform the 1,3‐stereodiad to 1,5‐ and 1,6‐stereochemical relationships. [ABSTRACT FROM AUTHOR]

Strategic design for the construction of contiguous tetrasubstituted carbon centers represents a daunting challenge in synthetic organic chemistry. Herein, we report a combined experimental and computational investigation aimed at developing catalytic aerobic carbooxygenation, involving the intramolecular addition of tertiary radicals to geminally disubstituted alkenes, followed by aerobic oxygenation. This reaction provides a straightforward route to various α,α,β,β‐tetrasubstituted γ‐lactones, which can be readily transformed into hexasubstituted γ‐lactones through allylation/translactonization. Computational analysis reveals that the key mechanistic foundation for achieving the developed aerobic carbooxygenation involves the design of endothermic (energetically uphill) C−C bond formation followed by exothermic (energetically downhill) oxygenation. Furthermore, we highlight a unique fluorine‐induced stereoelectronic effect that stabilizes the endothermic stereodetermining transition state. [ABSTRACT FROM AUTHOR]

The rising demand and financial costs of noble transition metal catalysts have emphasized the need for sustainable catalytic approaches. Over the past few years, base‐metal catalysts have emerged as ideal candidates to replace their noble‐metal counterparts because of their abundance and easiness of handling. Despite the significant advancements achieved with precious transition metals, earth‐abundant cobalt catalysts have emerged as efficient alternatives for allylic substitution reactions. In this review, allylic alkylations at sp3‐carbon centers mediated by cobalt will be discussed, with a special focus on the mechanistic features, scope, and limitations. [ABSTRACT FROM AUTHOR]

Herein we report the first transition metal‐catalyzed approach to the enantioenriched synthesis of cyclic sulfonimidamides relying on commercially available palladium catalysts and ligands. High‐throughput experimentation (HTE) was employed to identify the optimal catalyst system and solvent. The method is applied to a variety of saturated and unsaturated rings and exhibits the highest selectivity for 2‐substituted allyl electrophiles. The products are further elaborated to complex, tricyclic scaffolds. DFT experiments presented herein highlight the key ligand substrate interactions leading to the high levels of enantioselectivity. [ABSTRACT FROM AUTHOR]

A dual cobalt and chromium photoredox-catalyzed allylation of aldehydes with allenes through a photo metal-hydride atom transfer (MHAT) process has been developed to yield homoallylic alcohols with exceptional diastereoselective control. This sustainable and efficient method holds significant promise for applications in the synthesis of valuable organic compounds. [ABSTRACT FROM AUTHOR]

A highly enantioselective allylation/lactonization cascade was developed, which provides a concise and efficient route to chiral γ-butenolides under mild conditions. Most of the reaction examples can be completed in 10 minutes with high selectivity. [ABSTRACT FROM AUTHOR]

Allylation reactions, often used as a key step for constructing complex molecules and drug candidates, typically rely on transition‐metal (TM) catalysts. Even though TM‐free radical allylations have been developed using allyl‐stannanes, ‐sulfides, ‐silanes or ‐sulfones, much less procedures have been reported using simple and commercially available allyl halides, that are used for the preparation of the before‐mentioned allyl derivatives. Here, we present a straightforward photocatalytic protocol for the decarboxylative allylation of oxime esters using allyl bromide derivatives under metal‐free and mild conditions. This methodology yields a diverse variety of functionalized molecules including several pharmaceutically relevant molecules. [ABSTRACT FROM AUTHOR]

A convenient and straightforward approach for the construction of angular and linear indole scaffolds from commercially available β‐tetralones through a sequential methylation/ allylation/ propargylation followed by ring closing metathesis (RCM)/ [2+2+2] cyclotrimerization and Fischer indolization (FI) sequence has been described. The dipropargyl derivatives were further investigated for Sonogashira cross‐coupling with iodo‐benzene and click chemistry with benzyle azide to synthesize diverse indole motifs. The [2+2+2] cyclotrimerized products were treated with 3,5‐dimethyl aniline to obtain the product that resembles the structure of Alectinib, an FDA approved drug for the treatment of cancer. The approach provides a series of indole derivatives in moderate to good yields with excellent functional group tolerance and hence these compounds are utilized for molecular docking studies which shows good results. All the compounds synthesized here are well characterized by NMR and HRMS data. [ABSTRACT FROM AUTHOR]

A carbonyl‐assisted asymmetric 1,2‐migratory allylation through in situ generation of vicinal tetrasubstituted stereocenters is reported to access enantiopure α‐amino ketones and amino alcohols with excellent yields and diastereoselectivities. In a remarkable divergence, despite higher steric hindrance, the allylation exclusively occurs on ketones over imines in the first step, followed by a face‐selective 1,2‐allyl transfer, thus highlighting an exciting interplay between two distinct electrophiles. The methodology distinguishes itself through its adaptability to gram‐scale synthesis, showcasing broad functional‐group tolerance and stereodivergence. Density functional theory (DFT) analysis led to a deeper understanding of its selectivity and mechanistic framework. Highlighting its transformative potential, the method was applied to the total synthesis of hapalindole alkaloids. [ABSTRACT FROM AUTHOR]

Herein, we have demonstrated a palladium-catalyzed regioselective allylation of unactivated alkenes with vinylcyclopropanes assisted by weak-coordinating native amides. The reaction exhibits wide substrate scope and excellent β-selectivity. Substrate diversification was performed to demonstrate the synthetic utility of the reaction. Mechanistic investigations were carried out to provide an insight into the reaction mechanism. [ABSTRACT FROM AUTHOR]

An organophotoredox-catalyzed alkoxyallylation of feed-stock olefins, through thianthrenation using a Morita–Baylis–Hillman adduct as an allylating agent, is described. Site-selective addition of MeOH to an alkene-thianthrenium salt and its subsequent conversion into a nucleophilic radical species forms the basis of this unique difunctionalization strategy. The scope is also expanded into radical aryl allylation. [ABSTRACT FROM AUTHOR]

We describe a highly stereoconvergent radical epoxide allylation towards diastereomerically and enantiomerically enriched α‐quaternary alcohols in two steps from olefins. Our approach combines the stereospecifity and enantioselectivity of the Shi epoxidation with the unprecedented Ti(III)‐promoted intramolecular radical group transfer allylation of epoxides. A directional isomerization step via configurationally labile radical intermediates enables the selective preparation of all‐carbon quaternary stereocenters in a unique fashion. [ABSTRACT FROM AUTHOR]

The first palladium‐catalyzed allylation of isocyanoacetates with vinyl aziridines has been developed. The reaction conditions were suitable for a variety of α‐aryl isocyanoacetates as well as N‐substituted vinyl aziridines, affording the corresponding allylation products in moderate to high yields (up to 98 %) along with excellent stereoselectivity and regioselectivity. Transformations of the allylation products into trans‐4,5‐dehydrolysine analogues and a highly functionalized proline ester derivative were further demonstrated, and a preliminary asymmetric version of the reaction has also been evaluated. [ABSTRACT FROM AUTHOR]

We disclose herein an electrochemical allylation of unactivated aldehydes and ketones with allylic alcohols. A wide variety of homoallylic alcohols can be obtained by treatment of aldehydes/ketones with allyl alcohols in a simple undivided cell at room temperature. In contrast to previous strategies using allyl organometallic reagents, allylsilicon, allylboron and allyl halides as the allylic precursors, the present method used allyl alcohols as effective surrogates, which makes it more practical and environmentally sustainable. [ABSTRACT FROM AUTHOR]

The Pd‐catalysed decarboxylative asymmetric allylic alkylation (DAAA) of sterically hindered α‐aryl,β‐amido allyl ester lactams has been developed. The key step in the synthesis of a range of α‐aryl lactam substrates for catalysis was a Pb‐mediated α‐arylation of a β‐amido allyl ester affording 14 novel examples of α‐aryl‐β‐amido allyl ester lactams in good yields (up to 80 %). The Pd‐catalysed DAAA was optimised with the 2,4,6‐trimethoxyphenyl‐containing substrate. Using (S,S)‐DACH‐phenyl Trost as the optimal chiral ligand, enantioselectivities of up to 82 % ee were obtained. A substrate scope of 11 examples of α‐aryl‐β‐amido allyl ester lactams showed that products containing the di‐ortho‐methoxy‐substituted phenyls and naphthyl groups gave rise to the highest ees, whereas products not bearing this substitution pattern showed lower enantioselectivities (<60 % ee). Transition states to rationalise the observed stereochemical outcome are proposed. [ABSTRACT FROM AUTHOR]

Alkylation reactions are pivotal in organic chemistry, with wide‐ranging utilization across various fields of applied synthetic chemistry. However, conventional reagents employed in alkylations often pose substantial health and exposure risks. Quaternary ammonium salts (QAS) present a promising alternative for these transformations offering significantly reduced hazards as they are non‐cancerogenic, non‐mutagenic, non‐flammable, and non‐corrosive. Despite their potential, their use in direct organic transformations remains relatively unexplored. This review outlines strategies for utilizing QAS as alternative reagents in alkylation reactions, providing researchers with safer approaches to chemical synthesis. [ABSTRACT FROM AUTHOR]

This article explores the search for alternative energy and chemical sources in response to the depletion of fossil resources. It focuses on the synthesis of furanic diols from biomass feedstocks using a zinc/bismuth-mediated allylation reaction. The authors propose a user-friendly, inexpensive, and high-yielding green method for the synthesis of biobased diols. The article provides experimental results, optimization of reaction conditions, and a protocol for the synthesis of various allyl-substituted diols. It also includes chemical data and synthesis procedures for various compounds. The document concludes with an acknowledgment and dedication to Prof. Dennis Curran. [Extracted from the article]

Co(III)-catalysed site-selective C8-allylation and vinylation of isoquinolones with allyl acetate and vinyl acetates has been accomplished. The oxo group of isoquinolone has been utilised as an inherent directing group. Based on preliminary mechanistic studies, a plausible mechanism for the developed reaction has also been delineated. Broad substrate scope with good to excellent yields and post-synthetic transformations of allylated and vinylated isoquinolines highlight the importance of the reaction. [ABSTRACT FROM AUTHOR]

The use of gem‐difluorinated cyclopropanes (gem‐DFCPs) as fluoroallyl surrogates under transition‐metal catalysis has drawn considerable attention recently but such reactions are restricted to producing achiral or racemic mono‐fluoroalkenes. Herein, we report the first enantioselective allylation of indoles under rhodium catalysis with gem‐DFCPs. This reaction shows exceptional branched regioselectivity towards rhodium catalysis with gem‐DFCPs, which provides an efficient route to enantioenriched fluoroallylated indoles with wide substrate scope and good functional group tolerance. [ABSTRACT FROM AUTHOR]

Chiral trisubstituted vicinal diols are a type of important organic compounds, serving as both common structure units in bioactive natural products and chiral auxiliaries in asymmetric synthesis. Herein, by using siloxypropadienes as the precursors of allyl copper(I) species, a copper(I)‐catalyzed diastereoselective and enantioselective reductive allylation of ketones was achieved, providing both syn‐diols and anti‐diols in good to excellent enantioselectivity. DFT calculations show that cis‐γ‐siloxy‐allyl copper species are generated favorably with either 1‐TBSO‐propadiene or 1‐TIPSO‐propadiene. Moreover, the steric difference of TBS group and TIPS group distinguishes the face selectivity of acetophenone, leading to syn‐selectivity for 1‐TBSO‐propadiene and anti‐selectivity for 1‐TIPSO‐propadiene. Easy transformations of the products were performed, demonstrating the synthetic utility of the present method. Moreover, one chiral diol prepared in the above transformations was used as a suitable organocatalyst for the catalytic asymmetric reductive self‐coupling of aldimines generated in situ with B2(neo)2. [ABSTRACT FROM AUTHOR]

Transition-metal catalyzed allylic substitution reactions of alkenes are among the most efficient methods for synthesizing diene compounds, driven by the inherent preference for an inner-sphere mechanism. Here, we present a demonstration of an outer-sphere mechanism in Rh-catalyzed allylic substitution reaction of simple alkenes using gem-difluorinated cyclopropanes as allyl surrogates. This unconventional mechanism offers an opportunity for the fluorine recycling of gem-difluorinated cyclopropanes via C − F bond cleavage/reformation, ultimately delivering allylic carbofluorination products. The developed method tolerates a wide range of simple alkenes, providing access to secondary, tertiary fluorides and gem-difluorides with 100% atom economy. DFT calculations reveal that the C − C bond formation goes through an unusual outer-sphere nucleophilic substitution of the alkenes to the allyl-Rh species instead of migration insertion, and the generated carbon cation then forms the C − F bond with tetrafluoroborate as a fluoride shuttle. Allylic substitution reaction of alkenes has been well-developed, but it has limitations, partly due to the intrinsic predilection for an inner-sphere mechanism. Herein, the authors present an outer-sphere mechanism in Rh-catalyzed allylic substitution reaction of simple alkenes using gem-difluorinated cyclopropanes as allyl surrogates. [ABSTRACT FROM AUTHOR]

This document explores the regioselective N-allylation of various heterocycles using organoboron-palladium catalysis. The authors emphasize the significance of this reaction in organic synthesis, particularly in drug design. They discuss different methods for achieving selective N-alkylation or O-alkylation, including base-mediated reactions, transition-metal-catalyzed couplings, and O-to-N rearrangements. The authors then present their own protocol using organoboron catalysts in combination with a palladium/Xantphos complex to achieve N-allylation. They demonstrate the effectiveness of their method through successful allylation of different heterocycles. The document also discusses the use of arylboronic acid as a catalyst in palladium-catalyzed couplings of allylic alcohols with pyridones and related heterocycles, highlighting its potential advantages such as low palladium catalyst loadings and applicability to various heterocyclic scaffolds. Future research will focus on expanding this catalyst system to other types of transformations. [Extracted from the article]

This article discusses the development of a manganese(I)-catalyzed C–H allylation reaction for tryptophans and their oligopeptides. Peptides have become important therapeutic agents, and chemoselective modifications of amino acids or late-stage functionalizations of peptides are crucial for manipulating their properties. The use of water as a solvent in chemical reactions is gaining attention due to its environmental benefits, and this study successfully demonstrated the allylation of tryptophan in an aqueous medium. The reaction showed good efficacy at lower temperatures and with a low catalyst loading. The method was also applied to dipeptides, delivering the desired allylated products. [Extracted from the article]

Iridium-catalyzed dearomative allylation/acyl transfer rearrangement has been developed using easily available 2-pyridinyl benzoates and vinyl ethylene carbonate. This protocol enabled the expedient synthesis of a variety of chiral N-substituted 2-pyridones in good to high yields with excellent enantioselectivity. It has the advantages of high atom economy, wide substrate scope, gram-scale synthesis, and versatile synthetic transformations. [ABSTRACT FROM AUTHOR]

Germacranolides, secondary metabolites produced by plants, have garnered academic and industrial interest due to their diverse and complex topology as well as a wide array of pharmacological activities. Molephantin, a highly oxygenated germacranolide isolated from medicinal plants, Elephantopus mollis and Elephantopus tomentosus, has exhibited antitumor, inflammatory, and leishmanicidal activities. Its chemical structure is based on a highly strained ten‐membered macrocyclic backbone with an (E,Z)‐dienone moiety, which is fused with an α‐methylene‐γ‐butyrolactone and adorned with four successive stereogenic centers. Herein, we report the first synthesis of molephantin in 12 steps starting from readily available building blocks. The synthesis features the highly diastereoselective intermolecular Barbier allylation of the β,γ‐unsaturated aldehyde with optically active 3‐bromomethyl‐5H‐furan‐2‐one intermediate and ensuing Nozaki–Hiyama–Kishi (NHK) macrocyclization for the construction of the highly oxygenated ten‐membered macrocyclic framework. This synthetic route enabled access to another germacranolide congener, tomenphantopin F. Furthermore, cycloisomerization of molephantin into 2‐deethoxy‐2β‐hydroxyphantomolin could be facilitated by irradiation with ultraviolet A light (λmax=370 nm), which opened a versatile and concise access to the related furanogermacranolides such as EM‐2, phantomolin, 2‐O‐demethyltomenphantopin C, and tomenphantopin C. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: A Ru(II)‐catalyzed ortho allylation reaction of N‐aryl‐7‐azaindole with readily available 2‐methylidene cyclic carbonate has been developed. This reaction is an effective pathway for synthesizing 7‐azaindole derivatives with a wide scope of substrates and high yields. In addition, the method can be extended to the allylation of other heterocyclic compounds and several cyclic carbonates, highlighting the practicality of this strategy for synthesis. [ABSTRACT FROM AUTHOR]

This article discusses a new method for synthesizing spirocyclopentene oxindoles, which are found in natural products and biologically active molecules. The authors describe the synthesis process using lithium bis(trimethylsilyl)amide (LiHMDS) and ring closing metathesis. The yields of the desired compounds ranged from 55% to 88%, with some side products observed in certain cases. The authors provide detailed physical and spectroscopic data for each compound synthesized. The article acknowledges the institutions that provided resources and support for the research. [Extracted from the article]

gem‐Difluoroalkenes are unique structural motifs with important applications ranging from drugs to materials. Herein, we report a novel radical‐mediated defluorinative allylation of sulfamate esters with through distal C(sp3)−H functionalization under photoredox conditions. The reaction could readily incorporate various gem‐difluoroalkene motifs into previously unfunctionalized sp3 carbon centers. The transformation allows directly dual activation of N−H and C(sp3)−H bonds via a photocatalytic and redox‐neutral process, as well as using water as environmentally friendly co‐solvent. The reaction could provide a general and operationally simple method to access gem‐difluoroalkene compounds with high diversity. [ABSTRACT FROM AUTHOR]

A new application involving a water–stable amido–functionalized allylboronate has been developed for 1,2‐addition to carbon–nitrogen double bonds. The process achieves highly enantioselective allylation of aldoxime derivatives in water, by employing O‐Boc oximes as substrates under Zn(OH)2–chiral aminophenol catalysis. This process affords the corresponding homoallylic amines with 91–96 % ee. The products could be transformed into N‐hydroxy‐γ‐lactam or 1,2‐oxazinan‐6‐one, through an acidic or a protection‐acidic treatment sequence, respectively, almost without enantiopurity loss. [ABSTRACT FROM AUTHOR]

A palladium-catalyzed enantioselective umpolung allylation reaction of amido-tethered allyl carbonates with N-2,2,2-trifluoroethylisatin ketimines has been realized herein. The reaction worked well under mild reaction conditions to give various chiral oxindole derivatives in moderate to excellent yields with high enantioselectivities. Notably, this work represents the first Pd-catalyzed asymmetric umpolung allylation reaction of N-2,2,2-trifluoroethylisatin ketimines. [ABSTRACT FROM AUTHOR]

Stereoselective synthesis of the C21‐C41 fragment 4 of the reported structure of Neaumycin B(1), a 28‐membered macrolide compound with 19‐chiral centers and 6,6‐spiroketal structure, has been described. C21‐C27 fragment 5 was synthesized from the commercially available (S)‐Roche ester 7 using stereoselective allylation and Brown anti‐crotylation as key steps. C28‐C41 fragment 6 was constructed from chiral oxazolidinone auxiliary 13 using Evans syn‐aldol reaction, diastereoselective epoxidation, and (S)‐CBS reduction as key steps. Finally, boron‐mediated acetate aldol reaction of 5 and 6 led to the synthesis of C21‐C41 fragment 4 for the reported structure of Neaumycin B (1). [ABSTRACT FROM AUTHOR]

Pd2dba3·CHCl3 (2.5 mol%)-BINAPHANE (5 mol%) was used to promote the first catalytic enantioselective allylation of disubstituted ketenes to give α-allyl esters. The ester products were formed in good to excellent yields (61–93% yield for 13 examples, 16 examples in all), with moderate to good enantioselectivity (68–80% ee for 7 examples). [ABSTRACT FROM AUTHOR]

An N‐allylation of monosubstituted acyl hydrazines with allylic alcohols has been developed by using B(C6F5)3 catalysis. This protocol allows for convenient access to various synthetically useful N‐allylated hydrazine products in 48–96% yields with broad substrate scope and wide functional group compatibility. The operationally simple reaction proceeds without calling for stringent removal of air and moisture, and can be readily scaled up to gram scale. Preliminary mechanistic studies support the generation of an allylic carbon cation that is involved in the catalytic cycle, and the reaction proceeds via the in situ formation of diallyl ethers as intermediates. [ABSTRACT FROM AUTHOR]

This communication reports a four-step protocol to produce 3-allyl-2-(allyloxy)-5-bromoaniline 5 from commercially available 2-allylphenol. The synthetic steps used were nitration, selective bromination, allylation, and reduction of the nitro group. [ABSTRACT FROM AUTHOR]

Herein, we report a new synthetic route to 1,4-epoxy-2-aryltetrahydro-1-benzazepine derivatives with high efficiency, namely the Rh(III)-catalyzed C–H allylation of nitrones with allyl precursors, followed by subsequent intramolecular 1,3-dipolar cycloaddition, to deliver the title compounds. This reaction is regio- and stereo-selective, generating the cis-isomer with a broad substrate scope and good functional group tolerance. [ABSTRACT FROM AUTHOR]

A palladium-catalyzed allylation of hydrazines with allyl alcohols and aldehydes was developed, enabling the syntheses of a series of allylhydrazones in good to excellent yields with high regioselectivity. Furthermore, the four-component tandem allylation carbonylation of hydrazines with allyl alcohols and aldehydes was established using the catalytic system, producing various allyl acylhydrazones. Additionally, the functionalized allyl acylhydrazones could be smoothly constructed with the catalytic system employing allylhydrazones as a partner. The catalytic system exhibited good functional tolerance with excellent regioselectivities and scaled-up capability, overcoming the limitations of chemoselectivity of the multicomponent transformation and poor conversion of the weak nucleophile. [ABSTRACT FROM AUTHOR]

Cyclobutene scaffolds occur in natural products and bioactive compounds. Their unique structural features and intrinsic ring strain make cyclobutene a type of important building block in synthetic chemistry. In recent years, considerable efforts have been dedicated to the synthesis of chiral cyclobutenes. Enantioselective [2+2] cycloadditions and functionalization of cyclobutene derivatives have emerged as powerful and reliable protocols for achieving this goal, resulting in significant progress in this field. This review provides a comprehensive summary of the recent advancements in the asymmetric synthesis of chiral cyclobutenes, and the discussion is logically divided into four parts according to the reaction mode. [ABSTRACT FROM AUTHOR]

This review describes applications of radical reactions developed in the authors' laboratory for the modification of carbohydrates. It focuses on tin‐free variation on the Barton‐McCombie deoxygenation; on reductive de‐iodination; on intermolecular radical additions of xanthates; on allylations and vinylations of xanthates and iodides, with emphasis on allylations using allylic alcohols activated as fluoropyridyl ethers; and, finally, on the synthesis of mercaptosugars. [ABSTRACT FROM AUTHOR]

This article discusses the synthesis of a fragment of the anticancer drug eribulin mesylate. The synthesis was achieved by researchers from the Eisai pharmaceutical company in collaboration with Kishi et al. The article presents a practical and efficient approach to synthesizing a specific fragment of eribulin mesylate, starting from commercially available compounds. The authors have achieved the synthesis of this fragment in a convergent manner with an overall yield of 17.62%. Further research is being conducted to synthesize other fragments of eribulin mesylate. The text provides detailed information about the reaction conditions and the properties of the synthesized compounds. This information can be useful for researchers studying organic chemistry and related fields. [Extracted from the article]

The construction of acyclic, non‐adjacent 1,3‐stereogenic centers, prevalent motifs in drugs and bioactive molecules, has been a long‐standing synthetic challenge due to acyclic nucleophiles being distant from the chiral environment. In this study, we successfully synthesized highly valuable 1,2‐bis(boronic) esters featuring acyclic and nonadjacent 1,3‐stereocenters. Notably, this reaction selectively produces migratory coupling products rather than alternative deborylative allylation or direct allylation byproducts. This approach introduces a new activation mode for selective transformations of gem‐diborylmethane in asymmetric catalysis. Additionally, we found that other gem‐diborylalkanes, previously challenging due to steric hindrance, also successfully participated in this reaction. The incorporation of 1,2‐bis(boryl)alkenes facilitated the diversification of the alkenyl and two boron moieties in our target compounds, thereby enabling access to a broad array of versatile molecules. DFT calculations were performed to elucidate the reaction mechanism and shed light on the factors responsible for the observed excellent enantioselectivity and diastereoselectivity. These were determined to arise from ligand‐substrate steric repulsions in the syn‐addition transition state. [ABSTRACT FROM AUTHOR]

Functionalization of the C(sp3)−H bonds of trialkylamines is challenging, especially for reactions at positions other than the α position. Herein, we report a method for β‐C(sp3)−H allylation of trialkylamines. In these reactions, which involve synergistic borane/palladium catalysis, an enamine intermediate is first generated from the amine via α,β‐dehydrogenation promoted by B(C6F5)3 and a base, and then the enamine undergoes palladium‐catalyzed reaction with an allene to give the allylation product. Because the hydride and the proton resulting from the initial dehydrogenation are ultimately shuttled to the product by B(C6F5)3 and the palladium catalyst, respectively, these reactions show excellent atom economy. The establishment of this method paves the way for future studies of C−H functionalization of trialkylamines by means of synergistic borane/transition‐metal catalysis. [ABSTRACT FROM AUTHOR]

The significance of stereoselective C−H bond functionalization thrives on its direct application potential to pharmaceuticals or complex chiral molecule synthesis. Complication arises when there are multiple stereogenic elements such as a center and an axis of chirality to control. Over the years cooperative assistance of multiple chiral ligands has been applied to control only chiral centers. In this work, we harness the essence of cooperative ligand approach to control two different stereogenic elements in the same molecule by atroposelective allylation to synthesize axially chiral biaryls from its racemic precursor. The crucial roles played by chiral phosphoric acid and chiral amino acid ligand in concert helped us to obtain one major stereoisomer out of four distinct possibilities. [ABSTRACT FROM AUTHOR]

Catalytic asymmetric allylation of ketones under proton‐transfer conditions is a challenging issue due to the limited pronucleophiles and the electrophilic inertness of ketones. Herein, a copper(I)‐catalyzed asymmetric allylation of ketones with 2‐aza‐1,4‐dienes (N‐allyl‐1,1‐diphenylmethanimines) is disclosed, which affords a series of functionalized homoallyl tertiary alcohols in high to excellent enantioselectivity. Interestingly, N‐allyl‐1,1‐diphenylmethanimines work as synthetic equivalents of propanals. Upon the acidic workup, a formal asymmetric β‐addition of propanals to ketones is achieved. An investigation on KIE effect indicates that the deprotonation of N‐allyl‐1,1‐diphenylmethanimines is the rate‐determining step, which generates nucleophilic allyl copper(I) species. Finally, the synthetic utility of the present method is demonstrated by the asymmetric synthesis of (R)‐boivinianin A and (R)‐gossonorol. [ABSTRACT FROM AUTHOR]

We present the first solvent‐free, mechanochemical protocol for a palladium‐catalyzed Tsuji–Trost allylation. This approach features exceptionally low catalyst loadings (0.5 mol %), short reaction times (<90 min), and a simple setup, eliminating the need for air or moisture precautions, making the process highly efficient and environmentally benign. We introduce solid, nontoxic, and easy‐to‐handle allyl trimethylammonium salts as valuable alternative to volatile or hazardous reagents. Our approach enables the allylation of various O‐, N‐, and C‐nucleophiles in yields up to 99 % even for structurally complex bioactive compounds, owing to its mild conditions and exceptional functional group tolerance. [ABSTRACT FROM AUTHOR]

The Cp*Co(III) C−H allylation of (hetero)arenes with allyl aryl ethers has been developed using an amide as directing group (24 examples). DFT calculations have shed light on the mechanistic course and reactivity pattern, showing that strong electron releasing groups favour the reaction by reducing the activation barrier of the rate‐determining C−H activation step. However, the steric strain can increase the energy of the migratory insertion step to the point of completely preventing the reaction, as in the case of the 3,5‐dimethylbenzamide. The obtained allylated compounds have been transformed into a variety of interesting heterocyclic and carbocyclic structures, such as isoquinolones and isochromanones. [ABSTRACT FROM AUTHOR]

The fully functionalized A−F fragment of the Pacific ciguatoxin CTX3C has been synthesized from a derivative of D‐glucal, which serves as the B‐ring. Rings A and C were introduced to either side of ring B by ring‐closing diene and enyne metathesis (RCM). The seven‐membered D‐ring and eight‐membered E‐ring were assembled by iterative use of a six‐step reaction sequence in which RCM was used for ring construction and Tsuji–Trost allylation was employed for subsequent stereoselective functionalization. The nine‐membered F‐ring was formed by use of an RCM reaction and bears the functionality required for attachment of the I−M fragment and subsequent closure of rings G and H. [ABSTRACT FROM AUTHOR]

A unique Pd‐catalyzed approach for asymmetric (4+1) annulations via cascade allylation and transient σ‐alkyl‐Pd(II) initiated methylene Csp3−H activation is reported. The enolate fragment derived from the decarboxylation of vinyl methylene carbonate is crucial to stabilize the key intermediate. These reactions enable the synthesis of various useful dihydrobenzofurans with excellent enantioselectivity, typically >95 : 5 er, and exclusive (Z)‐stereoselectivity. Compared with the well‐established annulations via Heck‐type C−H activations, this protocol showcases a conceptually new way to generate σ‐alkyl‐Pd(II) species that could initiate challenging asymmetric Csp3−H activations. [ABSTRACT FROM AUTHOR]

This article explores the iridium-catalyzed asymmetric allylation of indoles using 1-alken-4-yn-3-ols. The researchers focus on optimizing the reaction by testing different additives and their impact on yield and enantioselectivity. The study provides valuable information on the synthesis of chiral polyacetylenic alcohols, which have important biological activities and potential applications in medicine. The reaction produces chiral allylated indoles and 1-alken-4-yn-3-ols with high enantioselectivities, demonstrating its compatibility with various functional groups. The findings also shed light on the absolute configuration of the products and have implications for the synthesis of chiral 1-alken-4-yn-3-ols. [Extracted from the article]