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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]

Sulfoxonium ylide chelation-assisted C–H allylation of arenes has been accomplished utilizing strained vinyl carbo/heterocycles as the allyl surrogates via sequential C–H and C–C/het bond activation. Broad substrate scope, Co-catalysis, selectivity, and late-stage drug mutation are the important practical features. [ABSTRACT FROM AUTHOR]

The limited nucleophilic character and the bidentate nature of unactivated nitroalkane anions (nitronates) makes the corresponding alkylation and allylation procedures rather troublesome. This aspect is in sharp contrast with other commonly employed processes involving nitronate anions such as conjugate additions or nitroaldol reactions. This review summarizes the most rewarding approaches that along the years have been devised to overcome this limitation. Efficient methods are nowadays mainly based on metal‐catalyzed processes involving purely ionic or mixed ionic‐radical intermediates including photoenzymatic reactions. [ABSTRACT FROM AUTHOR]

Lignin is the most abundant aromatic biopolymer, with a potential to serve as a building block of rigid and thermally stable bio‐based materials. However, it is still underutilized because of the heterogeneous and not fully understood chemical structure. Here, technical softwood Kraft lignin is refined in to narrow‐dispersity and relatively low molar mass fractions by microwave‐assisted processing, followed by microwave‐assisted allylation and further application in lignin‐based thermosets. This microwave processing is carried out under non‐catalyzed conditions using a low boiling point solvent and elevated pressure. The properties of the retrieved fractions are investigated by 31P‐NMR, heteronuclear single quantum coherence spectroscopy‐NMR, SEC, differential scanning calorimetry, and thermogravimetric analysis. The extraction yield of the selected lignin fraction is around 25%, with the number‐average molar mass (Mn), weight‐average molar mass (Mw), and dispersity (Đ) significantly reduced. The chemically modified lignin is characterized by 31P NMR and FTIR, which provides evidence of the introduction of the allyl moieties. The analyses demonstrate that 90 ± 3% of the hydroxyl groups in fractionated lignin are successfully allylated. Subsequently, the allylated lignin is cross‐linked through thermally induced thiol‐ene chemistry to produce lignin‐based thermosets. The final thermosets exhibit a storage modulus of 4050 ± 60 MPa and a Tg of 105 ± 5°C. [ABSTRACT FROM AUTHOR]

Functionalized triptycene derivatives have attracted significant research interest because of their potential applications in many research fields. Although the conventional Diels‐Alder reaction of anthracenes with benzynes has been a versatile synthetic tool for functionalized triptycenes, it is hardly possible to control the product regioselectivity. In this report, we demonstrate the selective synthesis of 1,8,13‐trisubstituted triptycenes by Pd‐catalyzed α‐bromination. As for the directing group, SMe group was the most effective to facilitate the halogenation of the proximal three benzene rings. The obtained product was further derivatized through allylation and Rh‐catalyzed hydroboration reactions. [ABSTRACT FROM AUTHOR]

Palladium-catalyzed allylation cyclization reaction has recently emerged as an efficient and powerful synthetic platform for the construction of diverse and valuable carbo- and heterocycles. Thus the development of new allylic motifs for achieving this type of transformations in high reactivity and selectivity is of great importance. Generally, these substrates have been utilized as 1,3-, 1,4-, 1,5-, 1,6-dipoles in many reactions, which are applied to prepare highly functionalized products with complete control of chemo-, regio-, diastereo-, and enantioselectivity. In this review, we focus our attention on the development of palladium-catalyzed [4 + n] cycloaddition of allylic motifs and describe a comprehensive and impressive advances in this area. Meanwhile, the related mechanism and the application of these annulation strategies in natural product total synthesis will be highlighted in detail. [ABSTRACT FROM AUTHOR]

Objectives. Catalytic processes involving norbornadiene (NBD) and norbornene (NBN) derivatives provide exceptional opportunities for the synthesis of a wide range of carbocyclic hydrocarbons. By significantly expanding this range, it becomes possible to obtain materials offering a wide variety of predictable properties. The aim of the present review is to summarize the latest achievements in the creation of novel processes catalyzed by palladium compounds. Considerable attention is paid to the study of the mechanisms of NBD allylation reactions by a combination of experimental and theoretical methods.Results. Various strategies of the molecular design of palladium catalysts for syntheses based on NBN and NBD are considered. The possibility of implementing various directions of NBD allylation is demonstrated. Factors influencing the direction of the reactions, by which means individual products can be selectively obtained, are discussed.Conclusions. The effective development of new catalytic processes involving NBD and NBN derivatives requires the complex application of synthetic, kinetic, isotopic, and quantum chemical approaches. By combining instrumental and theoretical methods with constant feedback, it becomes possible to optimize the search for original catalytic systems, obtain information about the mechanisms of their action, and influence technological parameters in a targeted manner.

We have summarized the developments and advancements of allyl-(aza)allyl coupling reactions in the past years. Since the first report in 1980, Pd-catalyzed allyl-allyl couplings have not drawn chemists' much attention for almost 20 years. Not until the last two decades, transition-metal-catalyzed allyl-(aza)allyl transformations have been retrieved vital interest and significantly developed in many respects, including metal-catalyst, ligand development, mechanistic understanding, substrate scope, and applications in the preparation of complex functional molecules. This review is organized according to the transition metals used in allyl-allyl coupling reactions including our own work. Besides, transition-metal-free, allyl-azaallyl cross-couplings and applications in the total synthesis of natural products and drugs have also been included.

Beyond the scope of classical Tsuji‐Trost reaction, an alkene bearing a remote leaving group is not considered as a potential substrate for allylation. The concept of migratory Tsuji‐Trost reaction focuses on the transformations with this type of substrates. Two pathways including olefin migration and leaving group migration to form typical allyl intermediate for following substitution have been explored to demonstrate the feasibility of this new concept. [ABSTRACT FROM AUTHOR]

We present a rapid (0.25–1 h), method to produce functionalised allylsilanes from readily available vinylsilanes. Employing a Brønsted acid catalysed dehydration as the key step, allylsilanes are produced in good yields (22–98%) and, in most cases, as a single geometric isomer. Furthermore, a possible allylation‐Cope pathway was discovered for certain substrates and attempts to optimise this are described. [ABSTRACT FROM AUTHOR]

The direct C−H functionalization of 1,2‐benzazaborines, especially asymmetric version, remains a great challenge. Here we report a palladium‐catalyzed enantioselective C−H olefination and allylation reactions of 1,2‐benzazaborines. This asymmetric approach is a kinetic resolution (KR), providing various C−B axially chiral 2‐aryl‐1,2‐benzazaborines and 3‐substituted 2‐aryl‐1,2‐benzazaborines in generally high yields with excellent enantioselectivities (selectivity (S) factor up to 354). The synthetic potential of this reaction is showcased by late‐stage modification of complex molecules, scale‐up reaction, and applications. [ABSTRACT FROM AUTHOR]

Within the field of lignin biorefining, significant research effort has been dedicated to the advancement of catalytic methods for lignocellulose depolymerization. However, another key challenge in lignin valorization is the conversion of the obtained monomers into higher value‐added products. To address this challenge, new catalytic methods that can fully embrace the inherent complexity of their target substrates are needed. Here, we describe copper‐catalyzed reactions for benzylic functionalization of lignin‐derived phenolics via intermediate formation of hexafluoroisopropoxy‐masked para‐quinone methides (p‐QMs). By controlling the rates of copper catalyst turnover and p‐QM release, we have developed copper‐catalyzed allylation and alkynylation reactions of lignin‐derived monomers to install various unsaturated fragments amenable to further synthetic applications. [ABSTRACT FROM AUTHOR]

This research was designed to isolate pinostrobin from Kaempferia pandurata Roxb. rhizome using a chromatography method and to study its structural modification through ethylation and allylation reactions. Two compounds were afforded from the ethylation reaction that were 5-ethoxy-7-methoxyflavanone and 4′-ethoxy-6′-methoxychalcone and in the case of the allylation, 5-O-allylpinostrobin (5-allyloxy-7-methoxyflavanone) and 6-allylpinostrobin (6-allyl-5-hydroxy-7-methoxyflavanone) were obtained. [ABSTRACT FROM AUTHOR]

A transition metal-free dehydrative allylation of stabilized P-ylides with activated allylic alcohols has been developed. This protocol utilizes a calcium catalyst to facilitate the cleavage of C–OH bonds and enables smooth dehydrative cross-coupling with P-ylides, resulting in water as the sole by-product. Remarkably, this transformation exhibits excellent tolerance towards a diverse range of allylic alcohols and P-ylides. Furthermore, the subsequent Wittig reaction affords a wide array of highly functionalized 1,4-dienes with high yields. [ABSTRACT FROM AUTHOR]

We report herein a regiodivergent and enantioselective allyl addition to ketones with allenylsilanes through copper catalysis. With the combination of CuOAc, a Josiphos‐type bidentate phosphine ligand and PhSiH3, allyl addition to a variety of ketones furnishes branched products in excellent enantioselectivities. The regioselectivity is completely reversed by employing the P‐stereogenic ligand BenzP*, affording the linear products with excellent enantioselectivities and good Z‐selectivities. The linear Z‐product could be converted to E‐product via a catalytic geometric isomerization of the Z‐alkene group. The silyl group in the products could provide a handle for downstream elaboration. [ABSTRACT FROM AUTHOR]

An efficient rhodium(III)‐catalysed C−H activation of 3‐aryl‐1‐H‐indazoles with easily available vinylethylene carbonate has been reported. A series of allyl alcohol substituted 3‐aryl‐1‐H‐indazoles were obtained with broad functional groups tolerance and favourable stereoselectivity. Notably, C−H and C−O bonds were selectively activated in "one pot" manner, releasing CO2 as the sole by‐product and avoiding external oxidant. This protocol provides a powerful approach for the post stage C−H allylation of indazole‐based substrates. [ABSTRACT FROM AUTHOR]

In recent years, there has been a concerted drive to develop methods that are greener and more sustainable. Being an earth‐abundant transition metal, cobalt offers an attractive substitute for commonly employed precious metal catalysts, though reactions engaging cobalt are still less developed. Herein, we report a method to achieve the decarboxylative allylation of nitrophenyl alkanes, nitroalkanes, and ketones employing cobalt. The reaction allows for the formation of various substituted allylated products in moderate‐excellent yields with a broad scope. Additionally, the synthetic potential of the methodology is demonstrated by the transformation of products into versatile heterocyclic motifs. Mechanistic studies revealed an in situ activation of the Co(II)/dppBz precatalyst by the carboxylate salt to generate a Co(I)‐species, which is presumed to be the active catalyst. [ABSTRACT FROM AUTHOR]

A simple synthetic approach has been developed for the enantioselective total synthesis of (+)-Sedridine, (-)-Allosedridine and their analogs such as (+)-N- Methyl Sedridine and (-)-N-Methylallosedridine. The synthesis was achieved by using commercially available starting materials via Maruoka-Keck allylation, Wacker oxidation, and CBS reduction. The synthetic root provides a good diastereomeric ratio and high yields. [ABSTRACT FROM AUTHOR]

A weak acyl chelation-assisted distal C4–H allylation of indoles has been accomplished using vinylcyclopropanes as an allylating agent under redox-neutral ruthenium(II) catalysis. The regioselectivity, removable directing group, substrate scope and diastereoselectivity are the important practical features. [ABSTRACT FROM AUTHOR]

First examples of the reactions of 3-trimethylsilyl-2-propynamides with organic diselenides yielding 3-alkylselanyl-2-propenamides and 3-organylselanyl-2-propynamides were realized. The latter compounds were obtained by the Cu-catalyzed reaction of organic diselenides with 4-propioloylmorpholine. The reaction of 3-trimethylsilyl-2-propynamides with dialkyl diselenides in the system NaBH4/H2O/K2CO3/THF proceeded in a regio- and stereoselective fashion, affording 3-alkylselanyl-2-propenamides in 90–94% yields. An unsymmetrical divinyl selenide with the cyclic amide groups and a product, containing two selanyl-2-propenamide moieties and three cyclic amide groups, were synthesized. The Cu-catalyzed allylation reaction of 3-trimethylsilyl-2-propynamides was accompanied with desilylation to yield 3-allyl-2-propynamides. [ABSTRACT FROM AUTHOR]

An efficient protocol for the carbozincation of allenamides with dialkylzinc reagents catalyzed by an NHC−Cu complex has been developed. This protocol could provide alkenylzinc species introducing the alkyl group to γ‐position and the zinc component to β‐position of the allenamides in a regio‐ and stereoselective manner. The resulting alkenylzinc species can undergo further C−C bond‐forming reactions, such as allylation, arylation, and benzoylation, affording a variety of β,β‐disubstituted enamides with well‐controlled configurations of the two substituents. Moreover, the chiral allenamide synthesized via this method can be converted to a chiral aminocyclopropane derivative. In view of the high regio‐ and stereoselectivity and the convenient one‐pot procedure, this sequential transformation protocol offers a potentially useful method for synthesizing multi‐substituted enamides, which are important compounds in synthetic organic chemistry. [ABSTRACT FROM AUTHOR]

The [Ru(p‐cymene)Cl2]2‐catalyzed reaction of 2‐arylpyridines with 1‐aryl‐2‐vinylpyrrolidines is carried out in CF3CH2OH at 40 °C in the presence of KOAc, affording ortho‐C−H allylation products of arenes in 29 % to 99 % yields and 1:0.7 to 1 : 5.4 Z/E ratio. The amino groups remain in the product molecules. The protocol suits for a wide scope of substrates and tolerates functional groups including alkyl, aryl, MeO, F, Cl, Br, OCF3, and CF3 groups. [ABSTRACT FROM AUTHOR]

The enantioselective catalytic cascade involving Tsuji–Trost allylation has provided a viable strategy for the construction of multiple asymmetric C–C and C–X centres and numerous methods have been developed around it for the synthesis of various vital scaffolds. The synthetic utility of this strategy was enhanced by replacing the customary allyl acetates with ethylene diacetates/dicarbonates, vinyl epoxides, vinyl oxetanes, vinyl ethylene carbonates, vinyl cyclopropanes, enynes, and dienes using transition-metal catalysis. One more milestone was achieved when metallaphotocatalysis provided the necessary platform for these cascades by using a cheaper metal. This review will provide a summary of these enantioselective catalytic cascades from 2015. [ABSTRACT FROM AUTHOR]

A facile and efficient synthesis of 3‐spiro cycloalkene fused 7‐aza‐2‐indalones from 3,3′‐di‐ or N,3,3′‐tri‐ allyl/homoallyl/pentenyl 7‐aza‐2‐indalones via ring‐closing metathesis (RCM) using Grubbs‐II catalyst has been achieved. The scope of the reaction has been demonstrated by synthesizing spiro products of various ring sizes (n=5, 7, and 18), utilizing 2‐indalone/7‐azaindalone and various alkenylation agents such as allyl/homoallyl/pentenyl bromides as substrates. In addition to usual RCM products, a cross metathesis (CM) product was observed when the substrate was N,3,3′‐triallylated derivative from 2‐indalone. Notably, a macrocyclic, 18‐membered bis‐spirodiene of N‐methyl‐7‐azaindalone was observed by means of intermolecular ring‐closing metathesis (RCM‐RCM). Also, Structures of a few representative spiro‐annulated products were evidenced with single crystal XRD analysis. Furthermore, a plausible mechanism for the products is discussed. [ABSTRACT FROM AUTHOR]

The Tsuji–Trost reaction between carbonyl compounds and allylic precursors has been widely used in the synthesis of natural products and pharmaceutical compounds. As the α‐C−H bond is far more acidic than the β‐C−H bond, carbonyl compounds undergo highly regioselective allylation at the α‐position and their β‐allylation is therefore highly challenging. This innate α‐reactivity conversely hampers diversity, especially if the corresponding β‐allylation product is targeted. Herein, we present a formal intermolecular β‐C−C bond formation reaction of a broad range of aldehydes and ketones with different allyl electrophiles through cooperative nickel and photoredox catalysis. β‐Selectivity is achieved via initial transformation of the aldehydes and ketones to their corresponding silyl enol ethers. The overall transformation features mild conditions, excellent regioselectivity, wide functional group tolerance and high reaction efficiency. The introduced facile and regioselective β‐allylation of carbonyl compounds proceeding through cooperative catalysis allows the preparation of valuable building blocks that are difficult to access from aldehydes and ketones using existing methodology. [ABSTRACT FROM AUTHOR]

The selective C7‐allylation of indolines with allyl bromide under ruthenium catalysis has been revealed here. Under established reaction conditions, C7‐allylation of various indolines, including drug compounds, was accomplished with good selectivity and yields. Based on combined experimental and density functional theory (DFT) studies, the olefin insertion route was energetically favorable among four possible pathways. Experimental and DFT studies further revealed that the C−H activation is a reversible rate‐limiting step. [ABSTRACT FROM AUTHOR]

Single C−F transformations of aromatic trifluoromethyl compounds are challenging issues due to the strong C−F bond. We have recently developed selective methods for single C−F transformations such as allylation of o‐hydrosilyl‐substituted benzotrifluorides through the hydride abstraction with trityl cations. Single C−F thiolation and azidation of o‐(hydrosilyl)benzotrifluorides were achieved using trityl sulfides and trityl azide catalyzed by Yb(OTf)3. Treatment of o‐(hydrosilyl)benzotrifluorides with trityl chloride resulted in single C−F chlorination. The resulting fluorosilyl group served in further transformations including protonation, halogenation, and Hiyama cross‐coupling with C−Si cleavage. We also synthesized benzyl fluorides by LiAlH4‐reduction of the resulting fluorosilanes and further C−F transformations. These methods enabled us to prepare a broad range of organofluorines from simple benzotrifluorides through C−F and C−Si transformations. [ABSTRACT FROM AUTHOR]

The synthesis of (E)-2-(1,3-diphenylallyl)-3,5-dimethoxyphenol is described by means of the reaction of 3,5-dimethoxyphenol with (E)-1,3-diphenylprop-2-en-1-ol in 1,1,1,3,3,3-hexafluoroispropanol (HFIP), which acts as a solvent and reaction promoter. The reaction proceeds smoothly to afford the mentioned compound in high yield under a metal and additive-free procedure. The corresponding allylated phenol has been fully characterized. [ABSTRACT FROM AUTHOR]

High-yielding and mild conditions are used to prepare of 1-bromo-2-alkyl- or 2-arylpent-4-en-2-ols/1-bromo-2-alkyl- or 2-arylpent-4-yn-2-ols from α-diazoketones. The reaction involves allylation/propargylation with successive bromide insertion using in situ generated allyltin bromide/or propargyltin bromide from activated tin metal and allyl/or propargyl bromide.

Latrunculins are marine toxins used in cell biology to block actin polymerization. The development of new synthetic strategies and methods for their synthesis is thus important in order to improve, modulate or control this biological value. The total syntheses found in the literature all target similar disconnections, especially an aldol strategy involving a recurrent 4-acetyl-1,3-thiazolidin-2-one ketone partner. Herein, we describe an alternative disconnection and subsequent stereoselective transformations to construct a stereopentade amenable to latrunculin and analogue synthesis, starting from (+)-β-citronellene. Key stereoselective transformations involve an asymmetric Krische allylation, an aldol reaction under 1,5-anti stereocontrol, and a Tishchenko–Evans reduction accompanied by a peculiar ester transposition, allowing to install key stereogenic centers of the natural products.

An atroposelective Ir‐catalyzed dynamic kinetic resolution (DKR) of 2‐(quinolin‐8‐yl)benzaldehydes/1‐naphthaldehydes by transfer hydrogenative coupling of allyl acetate is disclosed. The allylation reaction takes place with simultaneous installation of central and axial chirality, reaching high diastereoselectivities and excellent enantiomeric excesses when ortho‐cyclometalated iridium‐DM‐BINAP is used as the catalyst. The racemization of the substrates occurs through a designed transient Lewis acid‐base interaction between the quinoline nitrogen atom and the aldehyde carbonyl group. [ABSTRACT FROM AUTHOR]

Herein, we report a one‐pot method for enantioselective C−H allylation of pyridines at C3 via tandem borane and palladium catalysis. This method involves borane‐catalyzed pyridine hydroboration to generate dihydropyridines, then palladium‐catalyzed enantioselective allylation of the dihydropyridines with allylic esters, and finally air oxidation of the allylated dihydropyridines to afford the products. This method enables the introduction of an allylic group at C3 with excellent regio‐ and enantioselectivities. [ABSTRACT FROM AUTHOR]

Chain walking has been an efficient route to realize the functionalization of inert C(sp3)−H bonds, but this strategy is limited to mono‐olefin migration and functionalization. Herein, we demonstrate the feasibility of tandem directed simultaneous migrations of remote olefins and stereoselective allylation for the first time. The adoption of palladium hydride catalysis and secondary amine morpholine as solvent is critical for achieving high substrate compatibility and stereochemical control with this method. The protocol is also applicable to the functionalization of three vicinal C(sp3)−H bonds and thus construct three continuous stereocenters along a propylidene moiety via a short synthetic process. Preliminary mechanistic experiments corroborated the design of simultaneous walking of remote dienes. [ABSTRACT FROM AUTHOR]

A practical method for the preparation of quaternary and tertiary allyl‐substituted heteroarenes by site‐selective couplings of heteroaryl nitriles and allylic nucleophiles is disclosed. Transformations utilize readily accessible stable reagents, proceed in the presence of a Lewis base activator, and undergo aryl‐C(sp3) quaternary and tertiary carbon formation with high γ‐selectivity (up to >98 : 2 γ : α). [ABSTRACT FROM AUTHOR]

We report a general approach to highly functionalized (Z)-allylic amines by decarboxylative allylation of vinyloxazolidin-2-ones. This process engages sodium sulfinates as nucleophiles to form a new carbon–sulfur bond, utilizing a palladium catalyst generated from Pd(OAc)2 and diphosphine ligand dpppe. The scope of the protocol is illustrated by the synthesis of 30 representative allylic amines with high regio- and stereoselectivity. Mechanistic studies show that the Z-selectivity of the reaction stems from the formation of a palladacycle intermediate through Pd–N chelation. The synthetic utility of this method was further exemplified by the gram-scale synthesis and subsequent transformations to various compounds. [ABSTRACT FROM AUTHOR]

Reported in this work is a synergistic ternary achiral picolinaldehyde‐Zn(II)‐chiral palladium complex system for the highly enantioselective α‐allylation of N‐unprotected amino esters. By utilizing a variety of allylic carbonates or vinyl benzoxazinanones as substrates, α‐allyl α‐amino esters were obtained in high yields (up to 96 %) with high enantioselectivities (up to 98 % ee). Control experiments suggest that the coordination of Zn(II) with the Schiff base intermediate enhances the acidity of the α‐C−H bonds of amino esters, thereby favoring α‐allylation over intrinsic N‐allylation. Furthermore, NMR studies reveal an interaction between the chiral palladium complex and the Zn(II)‐Schiff base intermediate, leading to the formation of a picolinaldehyde‐Zn(II)‐Pd(0) catalytic system. [ABSTRACT FROM AUTHOR]

Merging C(sp2)–H allylation and alkene difunctionalization events to access isochroman-1-imines, using N-aroyl aminoesters, MBH acetates, and NBS, under Ru(II)/Ru(IV) catalysis has been developed. Using 1H NMR, ESI-MS, HRMS, control reactions, deuterium labeling experiments, and DFT analysis, the allyl transfer (redox) process was proven to involve in C–H allylation rather than olefin insertion. Scale-up and synthetic transformations demonstrated the sustainability of this method. [ABSTRACT FROM AUTHOR]