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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]

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]

This article explores the total synthesis of mavacuran alkaloids, focusing on bipleiophylline. The researchers from Université Paris-Saclay collaborated on this project and used bioinspired strategies to synthesize voacalgine A, bipleiophylline, and pleiocarpamine. The text discusses different approaches to the synthesis, including oxidative cyclization and intermolecular 1,4-addition reactions. While the authors were successful in synthesizing several mavacuran alkaloids, they were unable to achieve the required stereochemistry at C16. The article also mentions another group's recent publication on the total synthesis of pleiocarpamine. [Extracted from the article]

Serhiy Mykolayovych Reformatskyi, [Ukrainian: Рeφopмaтcьκий, Cepгiй Mиκoлaйoвич; Russian: Sergei Nikolaevich Reformatskii, РeΦopмaтcκий, Cepгeй Hиκoлaeвич (1860‐1934)] was a product of Zaitsev's laboratory in Kazan Imperial University in Russia and one of the founding fathers of organic chemistry in Ukraine. He discovered his eponymous reaction while a graduate student in Kazan under Zaitsev, studying the synthesis of homoallylic alcohols. He modified this reaction by replacing the olefinic π bond of an allyl halide with a carbonyl group. In the prototype reaction, he treated ethyl haloacetates with zinc and aldehydes or ketones. The reaction gave the corresponding β‐hydroxyesters and remains an important synthetic method. Work on the reaction over the ensuing century and a quarter has led to the discovery of analogous reactions using a wide range of metals, and even permitting the use of water as a solvent. [ABSTRACT FROM AUTHOR]

The chemical stability of the electrogenerated radical anion of N‐(aminobenzyl) phthalimide 1 in aprotic organic media at room temperature is reported in this work. The redox couples 1/1⋅− and its imine precursor 2/2⋅− can carry out reductive redox catalysis of benzyl or allyl halides indirectly. This reaction gives easy access to reactive alkyl radicals, which in the presence of diethyl fumarate yields 2‐benzylsuccinate diethyl ester in moderate yields; this reaction is unattainable by direct electrochemical reduction. Spin density calculations at the DFT level of theory showed that the spin density of 1⋅− and 2⋅− is located on the phtalimide ring, and a dimeric association was evidenced (Eint=23.47 kcal/mol and Eint=80.42 kcal/mol respectively), via π−π stacking interactions. The redox mediators presented here showed good functional group selectivity, redox potential tunability and easy preparation from readily available commercial materials with excellent yields. [ABSTRACT FROM AUTHOR]

The process of lactonization into an eight-membered compound occurs with the loss of two hydrogen atoms, the bromine atom involved in lactonization is absent in the benzoxazocinone molecule, which makes it possible to consider this heterocycle as a product of oxidative cyclization. Keywords: benzoxazepinone; halolactonization; atropisomer; glycine; benzoxazocinone; axial chirality EN benzoxazepinone halolactonization atropisomer glycine benzoxazocinone axial chirality 2053 2060 8 06/16/23 20230704 NES 230704 Benzoxazoheterocycles are the main structural element of some biologically active molecules, [1][2][3][4][5][6][7][8][9][10] and are also found in extracts obtained from natural sources (Figure 1). SP 1 sp H NMR (CDCl SB 3 sb , 500 MHz): = 7.32 (d, I J i = 7.6 Hz, 2 , 3', 5'), 7.23 (t, I J i = 7.3 Hz, 1 H, 4'), 7.10-7.07 (m, 3 H, ArH), 7.01 (d, I J i = 7.3 Hz, 1 H, Ar ), 6.91 (d, I J i = 7.3 Hz, 1 H, Ar ), 5.43-5.40 (m, 1 , 2"'), 4.63 (d, I J i = 16.5 Hz, 1 H, 2A), 3.77 (d, I J i = 16.5 Hz, 1 H, 2B), 3.73 (s, 3 H, OCH SB 3 sb ), 2.25 (s, 3 H, CH SB 3 sb ), 2.11-2.08, 1.94-1.91, 1.68-1.62 (m, 8 H, CH SB 2 sb CH SB 2 sb CH SB 2 sb CH SB 2 sb ). The reaction product was extracted with CH SB 2 sb Cl SB 2 sb (50 mL), the CH SB 2 sb Cl SB 2 sb layer was washed with H SB 2 sb O (10 mL) and dried (MgSO SB 4 sb ). [Extracted from the article]

A novel method of management of maize pathogens in vitro and in vivo using newly synthesized copper nanoparticles (CuNPs) has been documented in this study. CuNPs have been synthesized using CuSO4 as a precursor, NaBH4 and ascorbic acid as a reducing agent, and polyethylene glycol 8000 (PEG-8000) as a stabilizing agent. Characterization of CuNPs using a Transmission Electron Microscope (TEM) confirmed the nanoparticles' size range of 35–70 nm. Fourier transform infrared spectroscopy (FTIR) revealed the association of alcohol groups and allyl halides group with CuNPs. The synthesized CuNPs exhibited significant inhibition at 20 ppm of three pathogenic fungi namely Macrophomina phaseolina, Bipolaris maydis, and Fusarium verticillioides, and at 50 ppm against Rhizoctonia solani. Bactericidal property of CuNPs was evidenced against Erwinia carotovora and Ralstonia solanacearum at 30 ppm. Evaluation of CuNPs in vivo against two diseases viz., maydis leaf blight (MLB) and banded leaf and sheath blight (BLSB) culminated in a reduction in percent disease index (PDI). Seed treatment together with foliar spray @ 300 ppm of CuNPs resulted in a significant reduction of MLB. However, BLSB disease was reduced relatively less at the same aforesaid concentration nevertheless, it was evinced best in controlling BLSB disease. CuNPs were found inimical against beneficial fungi and bacteria. However, a positive effect was observed on soil enzyme activities namely dehydrogenase, urease, and alkaline phosphatase and maize seedling characters viz., shoot length, root length, number of roots per seedlings, fresh and dry weight. [ABSTRACT FROM AUTHOR]

In this personal account, our recent developments on the asymmetric synthesis of a quaternary carbon stereogenic center by organocatalysis using a primary amino acid and its salt as a catalyst are described in three chapters: (1) conjugate addition to nitroalkenes and vinyl ketones, (2) nucleophilic addition to π‐allyl palladium complexes, and (3) nucleophilic substitution reactions with allyl and propargyl halides. By these methods, asymmetric α‐allylation of α‐branched aldehydes and ketones smoothly proceeded to give γ‐nitroaldehydes, ketoaldehydes, α‐allylated aldehydes, and α‐allylated β‐ketoesters possessing a quaternary carbon stereogenic center in good yields with high enantioselectivities. [ABSTRACT FROM AUTHOR]

A facile method for the copper‐catalyzed synthesis of N‐benzyl‐N‐phenyl‐2‐benzothiazolamines was explored. In the presence of CuI, N‐phenylbenzothiazolamines was in situ generated from substituted 1‐(2‐iodophenyl)‐3‐phenylthioureas, which susequently underwent coupling with benzyl/allyl halides to give the desired N‐benzyl/allyl‐N‐phenyl‐2‐benzothiazolamines fluently in a one‐pot manner. The protocol features easy performance, easily available materials, good yield and broad substrates scope, showing potential synthetic value for the preparation of a variety of biologically or pharmaceutically active compounds. [ABSTRACT FROM AUTHOR]

C(sp3)−C(sp2) cross‐coupling reactions are an indispensable tool for organic synthesis. In these reactions transition metals have been extensively employed to promote the formation of valuable carbon‐carbon bonds. Herein, we report our recent discovery of a designer thioether as a highly active organocatalyst for reactions between an allyl bromide and an arylboronic acid. The cross‐coupling event occurred readily under mild condition in the presence of a weak inorganic base. Preliminary mechanistic studies suggested a sulfonium ylide mechanism. [ABSTRACT FROM AUTHOR]

Allyl halides with triflamide under oxidative conditions form halogen-substituted amidines. Allyl cyanide reacts with triflamide in acetonitrile or THF solutions in the presence of NBS to give the products of bromotriflamidation with a solvent interception, whereas in CH2Cl2 two regioisomers of the bromotriflamidation product without a solvent interception were obtained. The formed products undergo base-induced dehydrobromination to give linear isomers with the new C=C bond conjugated either with the nitrile group or the amidine moiety or alkoxy group. Under the same conditions, the reaction of allyl alcohol with triflamide gives rise to amidine, which was prepared earlier by the reaction of diallyl formal with triflamide. Unlike their iodo-substituted analogs, bromo-substituted amidines successfully transform into imidazolidines under the action of potassium carbonate. [ABSTRACT FROM AUTHOR]

A new mixed ligand Ni complex of phenolic Schiff base and 2,2' bipyridine was implanted on MCM-41 to prepare a simple and reusable catalyst. The designed heterogeneous catalyst has been characterized by FT-IR, PXRD analysis, N2 adsorption and desorption, SEM–EDX, TEM, ICP-OES and TGA. The synthesized Ni-MCM-41 is utilized as a potential catalyst against the Suzuki cross-coupling reaction of a wide range of aryl/alkyl/allyl halides with aryl boronic acid in DMF: water/water under microwave irradiation with the yield up to 95 / 86% of the catalytic product. Moreover, short reaction time, easy workup, eco-friendly, low cost and reusability of catalyst up to four times without a noteworthy loss of its activity are some of the merits of this method. The hot filtration test has been ratified that there was no leaching of metal during the catalytic reaction, indicating the heterogeneous manner of the catalyst. [ABSTRACT FROM AUTHOR]

A one‐pot three‐component reaction using p‐quinone methides, rongalite and alkyl/allyl halides has been described. The corresponding unsymmetrical sulfones were obtained in good yields under mild reaction conditions in the absence of any metal, base or any other additive. [ABSTRACT FROM AUTHOR]

Organochromium(III) species are multipurpose nucleophiles used in the synthesis of complex organic molecules due to their high functional group tolerance and extraordinary chemoselectivity for aldehydes. The preparation of organochromium(III) species starting from organic halides requires the use of a stoichiometric amount of chromium(II) salts or a catalytic amount of chromium(III) salts in the presence of stoichiometric reductants (such as Mn(0)). Recently, radicals formation from readily available alkenes, followed by their trapping with stoichiometric or catalytic amount of chromium(II) salts were reported in photoredox conditions for the generation of Cr(III) organometallic species. In this paper we disclose a real Nozaki‐Hiyama reaction (NH) in which photoredox conditions enable the preparation of Cr(III) allyl reagents starting from available allyl halides and stable Cr(III) salts. [ABSTRACT FROM AUTHOR]

It was found that in the presence of -cyclodextrins ( -CD), the ring opening reaction of epoxides with NaBH SB 4 sb in aqueous media proceeds smoothly with high regioselectivity, and racemic epoxides are kinetically resolved during the reaction (Scheme 20).[60] Graph: Scheme 20. A one-pot procedure has been provided for the synthesis of 2-iminium-1,3-dithiolanes from the BF SB 3 sb -OEt SB 2 sb catalyzed reaction of dithiocarbamic acid salts with styrene epoxide (Scheme 46).[116] Graph: Scheme 46. Upon treatment of the enol ester epoxides with I tert i -butyldimethylsilyl triflate in the presence of 2,6-lutidine, synthetically useful -silyloxyaldehydes were obtained.[111] Ni(III)-mandelate constitutes an efficient catalyst for the oxidative carbon-carbon cleavage of epoxides into carboxylic acids by DMSO (Scheme 42).[112] Graph: Scheme 42. Manufacturing of drugs The implications of epoxide ring opening in drug design for desired biologic action have been published.[157] Synthesis of AZD-4818 Astra Zeneca's compound AZD-4818 (Scheme 68) is a CCR1 antagonist and a clinical substance for the treatment of immune and inflammation disorders.[158] It is manufactured by ring opening of an epoxide (Scheme 68). [Extracted from the article]

Allyl halides with triflamide under oxidative conditions form halogen-substituted amidines. Allyl cyanide reacts with triflamide in acetonitrile or THF solutions in the presence of NBS to give the products of bromotriflamidation with a solvent interception, whereas in CH2Cl2 two regioisomers of the bromotriflamidation product without a solvent interception were obtained. The formed products undergo base-induced dehydrobromination to give linear isomers with the new C=C bond conjugated either with the nitrile group or the amidine moiety or alkoxy group. Under the same conditions, the reaction of allyl alcohol with triflamide gives rise to amidine, which was prepared earlier by the reaction of diallyl formal with triflamide. Unlike their iodo-substituted analogs, bromo-substituted amidines successfully transform into imidazolidines under the action of potassium carbonate.

Allylation of nucleophiles with highly reactive electrophiles like allyl halides can be conducted without metal catalysts. Less reactive electrophiles, such as allyl esters and carbonates, usually require a transition metal catalyst to facilitate the allylation. Herein, we report a unique transition-metal-free allylation strategy with allyl ether electrophiles. Reaction of a host of allyl ethers with 2-azaallyl anions delivers valuable homoallylic amine derivatives (up to 92%), which are significant in the pharmaceutical industry. Interestingly, no deprotonative isomerization or cyclization of the products were observed. The potential synthetic utility and ease of operation is demonstrated by a gram scale telescoped preparation of a homoallylic amine. In addition, mechanistic studies provide insight into these C(sp3)–C(sp3) bond-forming reactions. Allylation of nucleophiles with less reactive electrophiles, such as carbonates, usually requires a transition-metal catalyst. Here, the authors show a transition-metal-free allylation strategy with allyl ether electrophiles to form homoallylic amine derivatives in up to 92% yield. [ABSTRACT FROM AUTHOR]

Asymmetric Pd‐catalyzed Tsuji‐Trost‐type allylation is an important catalytic reaction toward chiral natural and unnatural product syntheses. We successfully modified a desalt‐type reaction using allyl ester or halide to a dehydrative one using allylic alcohol via the establishment of two redox‐mediated donor acceptor bifunctional catalyst systems. These systems were cationic CpRu‐Cl‐Napy‐PyCOOH and cationic CpRu‐Naph‐diPIM‐dioxo‐iPr/p‐TsOH and were designed on the basis of the soft ruthenium and hard Brønsted acid combined catalyst concept. The complementary use of the two chiral catalysts for dehydrative asymmetric allylation expands the application scope facilitating the utilization of both aliphatic and aromatic allylic alcohols with various nucleophiles in the substrate. In this account, the design, synthesis, and application of these catalysts were reported. [ABSTRACT FROM AUTHOR]

The possibility of constructing various N-, S-, O-containing heterocyclic systems based on the transformations of 1-((Z)-1,4-dibromobut-2-en-2-yl)adamantane was shown. Adamantyl-containing pyrrolines, pyrroles, pyridazinium salt, furan, thiophene, (dihydro)-1,6-benzodioxocine, diazocine, oxazocine, thiazocine were synthesized. It was found that the dihydro derivatives formed as a result of the reactions are unstable and can be easily oxidized by atmospheric oxygen to the corresponding heteroaromatic compounds. [ABSTRACT FROM AUTHOR]

In contrast to conventional metal–ligand cooperative cleavage of a B−H bond, which provides a B cation on the ligand and an H anion on the metal, we report herein the umpolung of B−H bonds by novel cyclopentadienone iridium complexes. The B−H bonds of 4,4,5,5‐tetramethyl‐1,3,2‐dioxaborolane (HBpin) and 1,8‐naphthalenediaminatoborane (HBdan) were cleaved to give a B anion on the metal and an H cation on the phenolic oxygen atom of the ligand. Mechanistic investigation by DFT calculations revealed that the alkoxycarbonyl‐substituted cyclopentadienone ligand facilitated deprotonation from Ir−H after oxidative addition of the B−H bond to give the umpolung product. The generated boryliridium complex was found to undergo borylation of an allyl halide in the presence of base, thus showing the nucleophilic nature of the boron atom. [ABSTRACT FROM AUTHOR]

A metal‐free synthesis of 2‐benzyl/allyl‐substituted thiobenzoazoles was developed starting from tetramethyl thiuram monosulfide (TMTM) which served as thiocarbonyl surrogate. By using 2‐aminophenols (or 2‐aminothiophenols, or 1,2‐phenylenediamines) and TMTM as starting materials, 2‐mercaptobenzoazoles could be synthesized efficiently. The subsequent C–S bond formation with benzyl/allyl halides gave the final products (2‐benzyl/allyl‐substituted thiobenzoazoles) with good to excellent yields. The metal‐free conditions, inexpensive and easily available starting materials, and broad substrate scope are the advantageous features of this protocol. [ABSTRACT FROM AUTHOR]

The carbon–carbon double bond formation via neodymium-mediated Barbier-type reaction of ketones and allyl halides in the presence of diethyl phosphite is reported for the first time. The reaction is highly α-regioselective and was conveniently carried out under mild conditions in a one-pot fashion. From a synthetic point of view, a series of conjugated alkenes were obtained in moderate to good yields in this one-pot reaction with feasible reaction conditions. [ABSTRACT FROM AUTHOR]

We report a range of highly regioselective openings of [1.1.1]propellane with various allylic zinc halides, as well as zinc enolates of ketones, esters and nitriles. The resulting zincated bicyclopentanes (BCPs) were trapped with a range of electrophiles including acyl chlorides, sulfonothioates, hydroxylamino benzoates, tosyl cyanide as well as aryl and allyl halides, generating highly functionalized BCP‐derivatives. The unusually high regioselectivity of these reactions has been rationalized using DFT calculations. A bioisostere of the synthetic opioid pethidine was prepared in 95 % yield in one step using this method. [ABSTRACT FROM AUTHOR]

Indium(I)/CuFe2O4 reagent for carbonyl allylation and epoxide rearranged carbonyl allylation is proposed for formation of homoallylic alcohols. The In(I) reagent in combination with catalytic amount of CuFe2O4 support in situ formation of nucleophilic allylic indium from allyl halide in THF medium. Nucleophilic allylic indium species react with carbonyls to form homoallyl alcohols in good to excellent yields. Under the presented reaction conditions arylepoxides undergo smooth rearrangement into aldehydes that are also allylated with formation of homoallyl alcohols. The process is highly efficient and tolerates different functional groups. [ABSTRACT FROM AUTHOR]

In this review article, the in situ formation of various organometallic reagents by electrochemical methods for addition (carbon–carbon bond) reactions is discussed. In this study, the organometallic complexes are formed by the insertion of a metal in an alkyl or allyl halide structure. Furthermore, the catalytic cycles of the studied metals on the surface of electrodes and in solutions may consist of oxidative addition, the reductive elimination of ligands, metal transformation, the production of metal ions, or cyclization processes. Different types of C–C bond formation, such as Csp2–Csp2, Csp2–Csp3, and Csp3–Csp3, using transition metal-catalyzed and electrochemical approaches (organometallic electrochemistry) are discussed. Moreover, variety of metals, such as Zn, Ni, Sm, In, Mn, Ru, Pd, Fe, and Cr, are investigated as catalysts in the formation of C–C bonds between two organic compounds. High atom economy; excellent isolated yields; sustainability; scalability; one-pot, simple, and mild reaction conditions; and the non-toxicity of reagents are known as some unique features of the electrochemical protocols for the synthesis of organic compounds. In recent years, organometallic electrochemical reactions have aided the formation of one of the most important bonds in the synthesis of new molecules. Some of the most famous of these protocols are the metal-catalyzed or metal-mediated electrochemical Barbier, Nozaki–Hiyama–Kishi, Reformatsky, and Barbier–Grignard-type reactions. This review offers an overview of the application of strategies and methodologies based on electrochemical methods and metal catalysts for the allylation and alkylation of chemical compounds. [ABSTRACT FROM AUTHOR]

A novel, useful in situ synthesis for NHC nickel allyl halide complexes [Ni(NHC)(η3‐allyl)(X)] starting from [Ni(CO)4], NHC and allyl halides is presented. The reaction of [Ni(CO)4] with (i) one equivalent of the corresponding NHC and (ii) with an excess of the corresponding allyl chloride at room temperature leads with elimination of carbon monoxide to complexes of the type [Ni(NHC)(η3‐allyl)(X)]. This approach was used to synthesize the complexes [Ni(tBu2Im)(η3‐H2C‐C(Me)‐CH2)(Cl)] (2), [Ni(iPr2ImMe)(η3‐H2C‐C(Me)‐CH2)(Cl)] (3), [Ni(iPr2Im)(η3‐H2C‐C(Me)‐CH2)(Cl)] (4), [Ni(iPr2Im)(η3‐H2C‐C(H)‐C(Me)2)(Br)] (5), [Ni(Me2ImMe)(η3‐H2C‐C(Me)‐CH2)(Cl)] (6), and [Ni(EtiPrImMe)(η3‐H2C‐C(Me)‐CH2)(Cl)] (7). The complexes 1 to 7 were characterized using NMR and IR spectroscopy and elemental analysis, and the molecular structures are provided for 2 and 7. The allyl nickel complexes 1–7 are stereochemically non‐rigid in solution due to (i) NHC rotation about the nickel‐carbon bond, (ii) allyl rotation about the Ni–η3‐allyl axis and (iii) π–σ–π allyl isomerization processes. The allyl halide complexes can be methylated as was demonstrated by the methylation of a number of the complexes [Ni(NHC)(η3‐allyl)(X)] with methylmagnesium chloride or methyllithium, which led to isolation of the complexes [Ni(Me2Im)(η3‐H2C‐C(Me)‐CH2)(Me)] (8), [Ni(tBu2Im)(η3‐H2C‐C(Me)‐CH2)(Me)] (9), [Ni(iPr2ImMe)(η3‐H2C‐C(Me)‐CH2)(Me)] (10), [Ni(iPr2Im)(η3‐H2C‐C(Me)‐CH2)(Me)] (11), [Ni(iPr2Im)(η3‐H2C‐C(H)‐C(Me)2)(Me)] (12), and [Ni(EtiPrImMe)(η3‐H2C‐C(Me)‐CH2)(Me)] (13). These complexes were fully characterized including X‐ray molecular structures for 10 and 11. [ABSTRACT FROM AUTHOR]

The article describes an unprecedented "ester dance" reaction: a predictable translocation of an ester group from one carbon atom to another on an aromatic ring. It discusses the ester moiety conversion to various aromatic derivatives through the use of classic and state-of-the-art transformations including amidation, acylations, and decarbonylative couplings.

A novel, air stable, water dispersible and efficient catalyst based on copper nanoparticles immobilized on nitrogen doped carbons derived from inorganic–organic composite [Cu(0)@NDC-Sil] has been prepared. Doping of carbons i.e. inorganic–organic (silica–starch) composite using 5-phenyl-1,2,3,4-tetrazole, a nitrogen-rich precursor imparts a variety of nitrogen functionalities even at moderate temperature and enables the generation of active sites for the immobilization of Cu(0) nanoparticles. The novel catalyst system has been well characterized by various techniques like SEM, HRTEM, STEM, TGA, CHN, EDX, ICP-AES, XRD and XPS and was found to be highly efficient for the one-pot synthesis of 1,4-disubstituted-1,2,3-triazoles via click chemistry approach with a wide range of substrate scope such as benzyl/allyl halides and alkyl bromides. Moreover, it could be easily recovered by filtration and reused without significant loss in its activity. [ABSTRACT FROM AUTHOR]

The photodissociation of allyl iodide (C3H5I) at 193 nm was investigated by using a combination of vacuum-ultraviolet photoionization of the allyl radical, resonant multiphoton ionization of the iodine atoms, and velocity map imaging. The data provide insight into the primary C–I bond fission process and into the dissociative ionization of the allyl radical to produce C3H3+. The experimental results are consistent with the earlier results of Szpunar et al. [J. Chem. Phys. 119, 5078 (2003)], in that some allyl radicals with internal energies higher than the secondary dissociation barrier are found to be stable. This stability results from the partitioning of available energy between the rotational and vibrational degrees of freedom of the radical, the effects of a centrifugal barrier along the reaction coordinate, and the effects of the kinetic shift in the secondary dissociation of the allyl radical. The present results suggest that the primary dissociation of allyl iodide to allyl radicals plus I*(2P1/2) is more important than previously suspected. [ABSTRACT FROM AUTHOR]

The properties of the five-dimensional branching space of conical intersections of three states of the same symmetry (denoted i,j,k) are considered. The results of a perturbative model are compared with multireference configuration interaction calculations for three spectroscopically observed states of the allyl radical. Of particular interest is the three-dimensional subspace of the branching space where two states remain degenerate. The energies, derivative couplings and geometric phase effect are studied in the neighborhood of this degeneracy subspace. The degeneracy subspace includes two kinds of conical intersections, i,j and j,k. The existence of a three-state intersection impacts the phase of the wave functions (and the derivative coupling) traversing a closed loop. For example, in the branching space, the number and kind of conical intersections in a surface bounding the closed loop is constrained if the closed loop contains the three-state intersection. © 2003 American Institute of Physics. [ABSTRACT FROM AUTHOR]

The photodissociation of allyl-d[sub 2] iodide (H[sub 2]C=CDCH[sub 2]I) and the dynamics of the nascent allyl-d[sub 2] radical (H[sub 2]CCDCH[sub 2]) were studied using photofragment translational spectroscopy. A previous study found the allyl radical stable at internal energies up to 15 kcal/mol higher than the 60 kcal/mol barrier to allene+H formation as the result of a centrifugal barrier. The deuterated allyl radical should then also show a stability to secondary dissociation at internal energies well above the barrier due to centrifugal effects. A comparison in this paper shows the allyl-d[sub 2] radical is stable to allene+D formation at energies of 2–3 kcal/mol higher than that of the nondeuterated allyl radical following photolysis of allyl iodide at 193 nm. This is most likely a result of a combination of the slight raising of the barrier from the difference in zero-point levels and a reduction of the impact parameter of the dissociative fragments due to the decrease in frequency of the C–D bending modes, and therefore allene+D product orbital angular momentum, |Lvector |=μ|vvector [sub rel]|b. The integrated signal taken at m/e=40 (allene) and m/e=41 (allene-d[sub 1] and propyne-d[sub 3]) shows a minor fraction of the allyl-d[sub 2] radicals isomerize to the 2-propenyl radical, in qualitative support of earlier conclusions of the domination of direct allene+H formation over isomerization. © 2003 American Institute of Physics. [ABSTRACT FROM AUTHOR]

In this study, we develop a nickel‐catalyzed carbonyl arylation reaction employing aldehydes with aryl and allyl halides. Various aryl, α,β‐unsaturated aldehyde and aliphatic aldehydes can be converted into their corresponding secondary alcohols in moderate‐to‐high yields. In addition, we extended this approach to develop an asymmetric reductive coupling reaction that combines nickel salts with chiral bisoxazoline ligands to give secondary alcohols with moderate enantioselectivity. [ABSTRACT FROM AUTHOR]

The transiently generated electrophilic terminal phosphinidene complex [(CO)5WPCH(SiMe3)2] reacted with allyl halides (X = F, Cl, Br) in toluene resulting in the formation of stable C–X insertion products 3a–c and diastereomeric phosphirane complexes 4a,a′,b,b′ as well as methylenephosphirane complex 5 as observed by 31P{1H} NMR spectroscopy. DFT calculations revealed that a novel rearrangement of transient phosphirane complexes is responsible involving C → P X atom transfer. [ABSTRACT FROM AUTHOR]

In this paper we report the design, synthesis and assessment of the first examples of self-immolative systems triggered by non-acidic electrophilic agents such as methyl, allyl or benzylic halides. These systems provide a visual colorimetric disclosure response upon exposure to these electrophilic reagents under mild, basic conditions without the need for the use of analytical instrumentation. [ABSTRACT FROM AUTHOR]

Reports on the direct observation of the products, kinetics and transitional energy release from the photodissociation of the allyl radical upon excitation in the near-ultraviolet. Allene formation being the dominant hydrogen-loss reaction channel; Appearance of hydrocarbon radicals as chemical intermediates in many reactive environments.

Highlights • A novel series of supramolecular catalysts were prepared and characterized by NMR, FT-IR, TEM, XRD, TGA, and XPS. • A picolinamide-modified β-cyclodextrin/Pd(II) complex showed very efficient catalytic activity for Suzuki-Miyaura coupling. • A proposed mechanism of the Pd(II)/Pd(IV) catalytic cycle was explored and calculated by ab initio QM/MM methods. • This hydrosoluble catalyst can be reused several times without a significant loss of activity. Abstract Novel supramolecular catalysts for Suzuki-Miyaura coupling were prepared and characterized by NMR, FT-IR, TEM, XRD, TGA, and XPS. The resulting picolinamide-modified β-cyclodextrin/Pd(II) complex (Pd(II)@PCA-β-CD) showed very efficient catalytic activity for Suzuki-Miyaura coupling of aryl, benzyl, and allyl halides with arylboronic acids in an environmentally benign aqueous solution. Various organic halides including chlorides can produce good to excellent yields with phenyl-boronic acid and a catalytic amount of Pd(II)@PCA-β-CD. This hydro-soluble catalyst was capable of being reused for at least eight runs with only a slight loss of catalytic activity. A putative mechanism of the Pd(II)/Pd(IV) catalytic cycle was also explored and calculated by ab initio QM/MM methods. [ABSTRACT FROM AUTHOR]

Keywords: Phthalimides; Redox mediators; Alkyl radicals; molecular redox catalysis; Indirect reduction EN Phthalimides Redox mediators Alkyl radicals molecular redox catalysis Indirect reduction 1 1 1 08/14/23 20230807 NES 230807 B The Cover Feature b shows "N-amino Benz" (N-(aminobenzyliden)- phthalimide) the protagonist of this article as an enthusiastic young scientist sharing his work. Cover Feature: N-(aminobenzyliden)phthalimides as a New Redox Mediator Family for the Selective Indirect Reduction of Benzyl or Allyl Halides (ChemCatChem 15/2023) In their Research Article, Bernardo A. Frontana-Uribe and co-workers demonstrate that N-(aminobenzyliden)phthalimides can act as a new redox mediator family for the selective indirect reduction of benzyl or allyl halides. [Extracted from the article]

Lignin is one of the major macromolecule in nature that contains an aromatic ring structure, and also a potential source of high-value products such as biofuels and chemicals. However, Lignin is a kind of complex heterogeneous polymer which can produce many degradation products during processing or treatment. These degradation products are difficult to separate, making it challenging to use lignin directly for high-value applications. This study proposes an electrocatalytic method to degrade lignin by using allyl halides to induce double-bonded phenolic monomers, while avoiding separation. In an alkaline solution, the three basic structural units (G, S, and H) of lignin were transformed into phenolic monomers by introducing allyl halide, which could effectively expand lignin application space. This reaction was achieved using a Pb/PbO 2 electrode as the anode and copper as the cathode. It was further confirmed that double-bonded phenolic monomers were obtained by degradation. 3-allylbromide has more active allyl radicals and significantly higher product yields than 3-allylchloride. The yields of 4-allyl-2-methoxyphenol, 4-allyl-2,6-dimethoxyphenol and 2-allylphenol could reach 17.21 g/kg-lignin, 7.75 g/kg-lignin, and 0.67 g/kg-lignin respectively. These mixed double-bond monomers can be used as monomer materials for in-situ polymerization without further separation, which lays the foundation for high value-added applications of lignin. [ABSTRACT FROM AUTHOR]

Herein, a general procedure to access CF2PO(OEt)2-containing molecules is reported. The reagent CuCF2PO(OEt)2 is accessible by a simple protocol and a broad range of substrates can be functionalised. The procedure allows the conversion of aryl diazonium salts, as well as aryl, heteroaryl, vinyl and alkynyl iodonium salts, into the corresponding fluorinated molecules at room temperature. Mechanistic studies were performed to gain a better understanding of the reaction pathway. Under similar conditions, vinyl and aryl iodides, allyl halides, and benzyl bromides were also functionalised, and the scope and limitations of the reaction were studied. Finally, the procedure was extended to disulfides to offer new access to SCF2PO(OEt)2-containing molecules. [ABSTRACT FROM AUTHOR]

Single enantiomer molecules are important for the pharmaceutical and agrochemical industries and increasingly so in materials science. Most strategies to obtain enantiomerically enriched molecules rely on either generating new stereogenic centres from prochiral substrates or resolving racemic mixtures of enantiomers. Dynamic asymmetric processes are powerful methods that use racemic mixtures of chiral substrates as starting material. This Feature Article focuses on asymmetric additions to racemic substrates using non-stabilized sp2- and sp3-hybridized nucleophiles. These reactions bear considerable resemblance to traditional sp2–sp2 cross-coupling reactions in terms of the starting materials used and the products obtained, but the reaction mechanisms are necessarily different. [ABSTRACT FROM AUTHOR]

The catalytic asymmetric α-functionaliza-tion of prochiral barbituric acids, a subtype of pseudosym-metric 1,3-diamides, to yield the corresponding 5,5-disubstituted (quaternary) derivatives remains essentially unsolved. In this study 2-alkylthio-4,6-dioxopirimidines are designed as key 1,3-diamide surrogates that perform exceedingly in amine-squaramide catalyzed C-C bond forming reactions with vinyl ketones or Morita-Baylis-Hillmann-type allyl bromides as electrophiles. Mild acid hydrolysis of adducts affords barbituric acid derivatives with an in-ring quaternary carbon in unprecedented enantioselectivity, offering valuable materials for biological evaluations. [ABSTRACT FROM AUTHOR]

A robust and rapid synthesis of 3-hydroxy-3-alkyl-2-oxindoles from isatins is described. This method introduces an ecofriendly, un-activated Zn dust, solid $$\hbox {NH}_{4}\hbox {Cl}$$ and substrates under aqueous conditions, which has produced the product in moderate to good yields. Without using column chromatography, majority of the compounds were isolated in analytically pure form. The progress of the reaction could be visualized by naked eye. Graphical Abstract: : SYNOPSIS A robust and rapid synthesis of 3-hydroxy-3-alkyl-2-oxindoles from isatins is described. This method introduces an ecofriendly method using un-activated Zn dust, solid $$\hbox {NH}_{4}\hbox {Cl}$$ and substrates under aqueous conditions, which has produced the products in moderate to good yields. [ABSTRACT FROM AUTHOR]

Et 3 B/O 2 -mediated radical coupling reactions of O,Te-acetal 2 were explored using diverse electrophilic double bonds. Ethyl radical derived from Et 3 B under air cleaved the C–Te bond of 2 to generate α-alkoxy bridgehead radical I , which reacted with cycloalkenones, cycloalkylidenemalononitriles, allyl halides, and imines at or below ambient temperature. These intermolecular reactions from O,Te-acetal 2 were mild and versatile, and were superior to those of O,Se-acetal 1 in terms of efficiency and substrate scope. A total of 14 new and nine improved coupling reactions are described, all of which realized the installation of the functionalized carbon units at the sterically hindered bridgehead position of trioxaadamantane. [ABSTRACT FROM AUTHOR]

Two ruthenium acetylide complexes [Ru]−C≡C−C≡C−C(OR)(C3H5)2 ( 2, R=H and 2 a, R=CH3; [Ru]=Cp(PPh3)2Ru) each with two cyclopropyl rings were synthesized from TMS−C≡C−C≡C−C(OH)(C3H5)2 ( 1; TMS=trimethylsilyl). Treatments of 2 and 2 a with allyl halide in the presence of KPF6 afforded the vinylidene complexes 3 and 3 a, respectively. When NH4PF6 was used, instead of KPF6, additional ring-opening reaction took place on one of the three-membered ring. Treatment of [Ru]Cl with 1,3-butadiyne ( 6), bearing an epoxide ring, afforded acetylide complex 7 with a furyl ring. Treatment of 2 a with Ph3CPF6 presumably afforded pentatetraenylidene complex {[Ru]=C=C=C=C=C(C3H5)2}[PF6] ( 10), which was not isolated. Additions of various alcohols in a solution of 10 generated a number of disubstituted allenylidene complexes {[Ru]=C=C=C(OR)−C=C(C3H5)2}[PF6] ( 11). Treatment of 11 with K2CO3 afforded the acetylide complex 12 bearing a carbonyl group, characterized by single X-ray diffraction analysis. Addition of a primary amine to 10 caused cleavage of the farthermost C=C bond and several allenylidene complexes {[Ru]=C=C=C(Me)(NHR)}[PF6] ( 18) were isolated. [ABSTRACT FROM AUTHOR]