Transition-metal-catalyzed laboratory-scale carbon-carbon bond-forming reactions of ethylene

Nickel-Catalyzed Reductive Alkene Cross-Dialkylation with Unactivated Alkyl Electrophiles

A Ni-catalyzed reductive dialkylation of 8-aminoquinoline-tethered aliphatic alkenes with two unactivated alkyl electrophiles is disclosed here. Key to the development of this transformation is the combination of primary alkyl (pseudo)halides and secondary alkyl iodides that produce products in a single regioselective manner. The reaction exhibits good functional group compatibility, and its synthetic utility was demonstrated by the concise synthesis of the precursors of biologically relevant molecules.

1,2-Fluorosulfenylation of unactivated alkenes with thiols and a fluoride source promoted by bromodimethylsulfonium bromide

A practical method that enables the fluorosulfenylation of unactivated alkenes processed directly with thiols and fluoride salts is presented. Good to excellent efficiencies and functional group tolerance are observed for both alkene substrates and thiols. The procedure also allows the use of gaseous ethylene as a two-carbon building block for β-fluoro thioether products.

Divergent and Selective Light Alkene Cross-Coupling

Light olefins are abundantly manufactured in the petroleum industry and thus represent ideal starting materials for modern chemical synthesis. Selective and divergent transformations of feedstock light olefins to value-added chemicals are highly sought-after but remain challenging. Herein we report an exceptionally regioselective carbonickelation of light alkenes followed by in situ trapping with three types of nucleophiles, namely a reductant, base, or Grignard reagent. This protocol enables efficient 1,2-hydrofunctionalization, dicarbofunctionalization, and branched-selective Heck-type cross-coupling of light alkenes with aryl and alkenyl reagents to streamline access to diverse alkyl arenes and complex alkenes. Harnessing bulky N-heterocyclic carbene ligands with acenaphthyl backbones for nickel catalysts is crucial to attain high reactivity and selectivity. This strategy provides a rare, modular, and divergent platform for upgrading feedstock alkenes and is expected to find broad applications in medicinal chemistry and industrial processes.

Asymmetric Intramolecular Hydroalkylation of Internal Olefin with Cycloalkanone to Directly Access Polycyclic Systems

An asymmetric intramolecular hydroalkylation of unactivated internal olefins with tethered cyclic ketones was realized by the cooperative catalysis of a newly designed chiral amine (SPD-NH2 ) and PdII complex, providing straightforward access to either bridged or fused bicyclic systems containing three stereogenic centers with excellent enantioselectivity (up to 99 % ee) and diastereoselectivity (up to >20 : 1 dr). Notably, the bicyclic products could be conveniently transformed into a diverse range of key structures frequently found in bioactive terpenes, such as Δ6 -protoilludene, cracroson D, and vulgarisins. The steric hindrance between the Ar group of the SPD-NH2 catalyst and the branched chain of the substrate, hydrogen-bonding interactions between the N-H of the enamine motif and the C=O of the directing group MQ, and the counterion of the PdII complex were identified as key factors for excellent stereoinduction in this dual catalytic process by density functional theory calculations.

Dehydrogenative Cross-Coupling of α,β-Unsaturated Compounds with Unactivated Olefins via Co(III) Catalysis

An oxidative cross-coupling of α,β-unsaturated compounds with unactivated alkenes via cobalt-catalyzed vinylic C-H activation has been developed. The present catalytic reaction was examined with various differently functionalized unsaturated compounds and unactivated olefins. In these reactions, highly valuable amide functionalized butadienes and indenones were prepared in good to excellent yields. A possible reaction mechanism is proposed involving directed olefinic C-H activation through a base-assisted deprotonation pathway.

Iridium-Catalyzed Branch-Selective Hydroalkylation of Simple Alkenes with Malonic Amides and Malonic Esters

We report the iridium-catalyzed branch-selective hydroalkylation of simple alkenes such as aliphatic alkenes and aromatic alkenes with malonic amides and malonic esters under neutral reaction conditions. A variety of aliphatic alkenes and aromatic alkenes bearing bromine, chlorine, ester, 2-thienylcarboxylate, silyl, and phthalimide groups were all found to be suitable for this hydroalkylation. The combination of this method with Krapcho dealkoxycarbonylation realized a one-pot synthesis of β-substituted amide and ester from β-amide ester and malonic ester. The hydroalkylated products derived from malonic amides are suitable for further transformation. The finely tuned reaction conditions realized the selective transformation of hydroalkylated products to 1,3-diamines or monoamides with the same reagent. Deuterium labeling experiments and measurement of the kinetic isotope effect indicated that the catalytic cycle involves a reversible step and cleavage of the C-H bond is not a rate-determining step. Density functional theory calculations provided insight into the reaction mechanism, where the carboiridation step is followed by C-H reductive elimination.

Palladium(II)-Catalyzed Regioselective Hydrocarbofunctionalization of N-Alkenyl Amides: Synthesis of Tryptamine Derivatives

The hydrocarbofunctionalization of allyl amines connected to the picolinamide directing group is developed under Pd(II) catalysis. The strategy is grounded on a nucleopalladation concept, and a wide range of indoles effectively participated to produce valuable tryptamine derivatives in high yields. Synthetic utilities were showcased through the substrate diversification bearing bioactive core, Pictet-Spengler cyclization, and β-carboline synthesis. A mechanistic study suggested an irreversible nucleopalladation step, while protodepalladation follows a reversible pathway.

A theory-driven synthesis of symmetric and unsymmetric 1,2-bis(diphenylphosphino)ethane analogues via radical difunctionalization of ethylene

1,2-Bis(diphenylphosphino)ethane (DPPE) and its synthetic analogues are important structural motifs in organic synthesis, particularly as diphosphine ligands with a C₂-alkyl-linker chain. Since DPPE is known to bind to many metal centers in a bidentate fashion to stabilize the corresponding metal complex via the chelation effect originating from its entropic advantage over monodentate ligands, it is often used in transition-metal-catalyzed transformations. Symmetric DPPE derivatives (Ar¹₂P-CH₂-CH₂-PAr¹₂) are well-known and readily prepared, but electronically and sterically unsymmetric DPPE (Ar¹₂P-CH₂-CH₂-PAr²₂; Ar¹≠Ar²) ligands have been less explored, mostly due to the difficulties associated with their preparation. Here we report a synthetic method for both symmetric and unsymmetric DPPEs via radical difunctionalization of ethylene, a fundamental C₂ unit, with two phosphine-centered radicals, which is guided by the computational analysis with the artificial force induced reaction (AFIR) method, a quantum chemical calculation-based automated reaction path search tool. The obtained unsymmetric DPPE ligands can coordinate to several transition-metal salts to form the corresponding complexes, one of which exhibits distinctly different characteristics than the corresponding symmetric DPPE-metal complex.

Regioselective catalytic carbonylation and borylation of alkynes with aryldiazonium salts toward α-unsubstituted β-boryl ketones

A new Pd/Cu-catalyzed carbonylation and borylation of alkynes with aryldiazonium salts toward α-unsubstituted β-boryl ketones with complete regioselectivity has been developed. This transformation shows broad substrate scope and excellent functional-group tolerance. Moreover, the obtained 1,2-carbonylboration products provide substantial opportunities for further transformations which cannot be obtained by known carbonylation procedures. Preliminary mechanistic studies indicate that the three hydrogen atoms of the products originated from ethyl acetate.

Visible-Light-Driven [3 + 2]/[4 + 2] Annulation Reactions of Alkenes with N-Aminopyridinium Salts

The annulation reactions of benzoamidyl radicals with alkenes were realized under visible light irradiation with fac-Ir(ppy)₃ as catalyst and N-aminopyridinium salts as benzoamidyl radical precursors. The reaction can deliver two distinct types of products: in the case of vinyl arenes, [3 + 2] annulation product dihydrooxazoles were yielded exclusively; when alkyl-substituted alkenes were used, on the other hand, it afforded [4 + 2] annulation product dihydroisoquinolinones. Factors determining the reaction consequence were elucidated by DFT calculations.

Mechanisms, Challenges, and Opportunities of Dual Ni/Photoredox-Catalyzed C(sp2)-C(sp3) Cross-Couplings

The merging of photoredox and nickel catalysis has revolutionized the field of C-C cross-coupling. However, in comparison to the development of synthetic methods, detailed mechanistic investigations of these catalytic systems are lagging. To improve the mechanistic understanding, computational tools have emerged as powerful tools to elucidate the factors controlling reactivity and selectivity in these complex catalytic transformations. Based on the reported computational studies, it appears that the mechanistic picture of catalytic systems is not generally applicable, but is rather dependent on the specific choice of substrate, ligands, photocatalysts, etc. Given the complexity of these systems, the need for more accurate computational methods, readily available and user-friendly dynamics simulation tools, and data-driven approaches is clear in order to understand at the molecular level the mechanisms of these transformations. In particular, we anticipate that such improvement of theoretical methods will become crucial to advance the understanding of excited-state properties and dynamics of key species, as well as to enable faster and unbiased exploration of reaction pathways. Further, with greater collaboration between computational, experimental, and spectroscopic communities, the mechanistic investigation of photoredox/Ni dual-catalytic reactions is expected to thrive quickly, facilitating the design of novel catalytic systems and promoting our understanding of the reaction selectivity.

Diverse synthesis of C2-linked functionalized molecules via molecular glue strategy with acetylene

As the simplest alkyne and an abundant chemical feedstock, acetylene is an ideal two-carbon building block. However, in contrast to substituted alkynes, catalytic methods to incorporate acetylene into fine chemicals are quite limited. Herein, we developed a photoredox-catalyzed synthetic protocol for diverse C2-linked molecules via a molecular glue strategy using gaseous acetylene under mild conditions. Initiated by addition of an acyl radical to acetylene, two cascade transformations follow. One involves a double addition for the formation of 1,4-diketones and the other where the intermediate vinyl ketone is intercepted by a radical formed from a heterocycle. In addition to making two new C-C bonds, two C-H bonds are also created in two mechanistically distinct ways: one via a C-H abstraction and the other via protonation. This system offers a reliable and safe way to incorporate gaseous acetylene into fine chemicals and expands the utility of acetylene in organic synthesis.

Although acetylene is an ideal two-carbon building block, very few catalytic methods can be applied to incorporate acetylene into fine chemicals. Here, the authors show photoredox-catalyzed syntheses of C2- linked molecules with gaseous acetylene under mild conditions.

Palladium-Catalyzed Carbonylation of Disulfides and Ethylene: Synthesis of β-Thiopropionate Thioesters

Transforming carbon monoxide (C1) and ethylene (C2) into high value-added chemicals is of great significance from an economic perspective, especially to multifunctionalized C3 compounds. Herein, we developed a palladium-catalyzed thiocarbonylative 1,2-difunctionalization of ethylene. Employing NiXantPhos as the ligand and DCE as the solvent, a series of organic disulfides can be successfully transformed into β-thiopropionate thioesters in good yields.

Recent advances in transition metal-catalyzed heteroannulative difunctionalization of alkenes via C-H activation for the synthesis of heterocycles

Heterocyclic compounds are the fundamental structural motifs distributed in natural products, pharmaceuticals and biologically active compounds. Thus, there is increasing interest in the development of novel synthetic strategies for the...

Cooperative Cu/Pd-catalyzed borocarbonylation of ethylene

A general procedure for the synthesize of β-boryl ketones enabled by cooperative Cu/Pd-catalyzed borocarbonylation of ethylene has been developed.

Palladium-Catalyzed Direct Dicarbonylation of Amines with Ethylene to Imides

The selective and effective conversion of low-cost and simple bulk chemicals into high value-added products through catalytic strategy has a wide range of practical significance. Here, a palladium-catalyzed method for the direct and efficient dicarbonylation of amines with basic industrial feedstock ethylene to imide has been developed. Moderate to excellent yields of the desired imides can be produced from readily available amines in a straightforward manner.

Radical Difunctionalization of Gaseous Ethylene Guided by Quantum Chemical Calculations: Selective Incorporation of Two Molecules of Ethylene

Ethylene, of which about 170 million tons are produced annually worldwide, is a fundamental C₂ feedstock that is widely used on an industrial scale for the synthesis of polyethylenes and polyvinylchlorides. Compared to other alkenes, however, the direct use of ethylene for the synthesis of fine chemicals such as pharmaceuticals and agrochemicals is limited, probably due to its small and gaseous character. We, herein, report a new radical difunctionalization strategy of ethylene, aided by quantum chemical calculations. Computationally proposed imidyl and sulfonyl radicals can be introduced into ethylene in the presence of an Ir photocatalyst under irradiation with blue light-emitting diodes (LEDs) (λ_max = 440 nm). The present reaction systems led to the selective incorporation of two molecules of ethylene into the substrate, which could be rationally explained by computational analysis.

Nickel-catalyzed enantioselective 1,2-vinylboration of styrenes

A novel nickel-catalyzed asymmetric 1,2-vinylboration reaction has been developed to afford benzylic alkenylboration products with high yields and excellent enantioselectivities by using a chiral bisoxazoline ligand. Under optimized conditions, a wide variety of chiral 2-boryl-1,1-arylvinylalkanes are efficiently prepared from readily available olefins and vinyl halides in the presence of bis(pinacolato)diboron as the boron source in a mild and easy-to-operate manner. This three-component cascade protocol furnishes exceptional chemo- and stereoselectivity, and its usefulness is illustrated by its application in asymmetric modifications of several structurally complex natural products and pharmaceuticals.

A novel nickel-catalyzed asymmetric 1,2-vinylboration reaction has been developed to afford benzylic alkenylboration products with high yields and excellent enantioselectivities by using a chiral bisoxazoline ligand.

Ni-catalyzed hydroalkylation of olefins with N-sulfonyl amines

Hydroalkylation, the direct addition of a C(sp³)–H bond across an olefin, is a desirable strategy to produce valuable, complex structural motifs in functional materials, pharmaceuticals, and natural products. Herein, we report a reliable method for accessing α-branched amines via nickel-catalyzed hydroalkylation reactions. Specifically, by using bis(cyclooctadiene)nickel (Ni(cod)₂) together with a phosphine ligand, we achieved a formal C(sp³)–H bond insertion reaction between olefins and N-sulfonyl amines without the need for an external hydride source. The amine not only provides the alkyl motif but also delivers hydride to the olefin by means of a nickel-engaged β–hydride elimination/reductive elimination process. This method provides a platform for constructing chiral α-branched amines by using a P-chiral ligand, demonstrating its potential utility in organic synthesis. Notably, a sulfonamidyl boronate complex formed in situ under basic conditions promotes ring-opening of the azanickellacycle reaction intermediate, leading to a significant improvement of the catalytic efficiency.

Catalytic addition of a carbon chain and a hydrogen across a double bond has often required an added hydride source. Here the authors show a method to add alkanes with an amino functionality to olefins, wherein a nickel catalyst uses the amine itself as the hydride source, obviating an external hydride reagent.

Photoredox/nickel-catalyzed hydroacylation of ethylene with aromatic acids

We report a general, practical and scalable hydroacylation reaction of ethylene with aromatic carboxylic acids with the synergistic combination of nickel and photoredox catalysis. Under ambient temperature and pressure, feedstock chemicals such as ethylene can be converted into high-value-added aromatic ketones in moderate to good yields (up to 92%) with reaction time of 2-6 hours.

Vinyl Thianthrenium Tetrafluoroborate: A Practical and Versatile Vinylating Reagent Made from Ethylene

The use of vinyl electrophiles in synthesis has been hampered by the lack of access to a suitable reagent that is practical and of appropriate reactivity. In this work we introduce a vinyl thianthrenium salt as an effective vinylating reagent. The bench-stable, crystalline reagent can be readily prepared from ethylene gas at atmospheric pressure in one step and is broadly useful in the annulation chemistry of (hetero)cycles, N-vinylation of heterocyclic compounds, and palladium-catalyzed cross-coupling reactions. The structural features of the thianthrene core enable a distinct synthesis and reactivity profile, unprecedented for other vinyl sulfonium derivatives.

Effect of Transition Metals on Chemodivergent Cross-Coupling of Acrylamides with Vinyl Acetate via C-H Activation

A novel chemodivergent cross-coupling of acrylamides and vinyl acetates has been realized via metal-catalyzed vinylic C-H activation. The selective olefinic C-H vinylation and alkenylation reaction was examined with a variety of differently functionalized acrylamides. The reaction efficiently generates a range of highly synthetically valuable butadienes with good functional group tolerance in good to moderate yields. A possible catalytic reaction mechanism involving the chelation-assisted olefinic C-H activation via an acetate-assisted deprotonation pathway is proposed.

Reactions of diborenes with terminal alkynes: mechanisms of ligand-controlled anti-selective hydroalkynylation, cycloaddition and C[triple bond, length as m-dash]C triple bond scission

The reactions of terminal acetylenes with doubly Lewis base-stabilised diborenes resulted in different outcomes depending on the nature of the ligands at boron and the conformation of the diborene (cyclic versus acyclic). N-heterocyclic carbene (NHC)-stabilised diborenes tended to undergo anti-selective hydroalkynylation at room temperature, whereas [2 + 2] cycloaddition was observed at higher temperatures, invariably followed by a C–N bond activation at one NHC ligand, leading to the ring-expansion of the initially formed BCBC ring and formation of novel boron-containing heterocycles. For phosphine-stabilised diborenes only [2 + 2] cycloaddition was observed, followed by a rearrangement of the resulting 1,2-dihydro-1,2-diborete to the corresponding 1,3-isomer, which amounts to complete scission of both the B Created by potrace 1.16, written by Peter Selinger 2001-2019 ]]> B double and CC triple bonds of the reactants. The elusive 1,2-isomer was finally trapped by using a cyclic phosphine-stabilised diborene, which prevented rearrangement to the 1,3-isomer. Extensive density functional theory (DFT) calculations provide a rationale for the selectivity observed.

The outcome of reactions between diborenes and terminal alkynes can be tuned by varying the stabilising Lewis base and/or reaction conditions, to yield either the anti-hydroalkynylation product or [2 + 2] cycloaddition-derived boron heterocycles.

Mechanisms and origins of regioselectivities of nickel-catalyzed β,δ-vinylarylation of alkenyl esters with vinyl triflates and arylzinc reagents

DFT calculations were performed to explore the mechanisms, origins of regioselectivity and substituent-controlled reactivity in the β,δ-vinylarylation of alkenyl esters catalyzed by nickel catalysts.

Nickel-catalyzed alkenylboration of alkenylarenes to access homoallylic boronic esters

A practical nickel-catalyzed alkenylboration of alkenylarenes with excellent chemo- and regio-selectivity has been developed.

Alkyl halides as both hydride and alkyl sources in catalytic regioselective reductive olefin hydroalkylation

Among the plethora of catalytic methods developed for hydrocarbofunctionalization of olefins to date, reactions that regioselectively install a functionalized alkyl unit at the 2-position of a terminal unactivated C=C bond to afford branched products are scarce. Here, we show that a Ni-based catalyst in conjunction with a stoichiometric reducing agent promote Markovnikov-selective hydroalkylation of unactivated alkenes tethered to a recyclable 8-aminoquinaldine directing auxiliary. These mild reductive processes employ readily available primary and secondary haloalkanes as both the hydride and alkyl donor. Reactions of alkenyl amides with ≥ five-carbon chain length regioselectively afforded β-alkylated products through remote hydroalkylation, underscoring the fidelity of the catalytic process and the directing group’s capability in stabilizing five-membered nickelacycle intermediates. The operationally simple protocol exhibits exceptional functional group tolerance and is amenable to the synthesis of bioactive molecules as well as regioconvergent transformations.

Methods that regioselectively install a functionalized alkyl unit at the 2-position of a terminal unactivated C=C bond are scarce. Here, the authors report a Markovnikov-selective hydroalkylation of unactivated amide-tethered alkenes catalyzed by nickel in conjunction with a stoichiometric reductant.

Fe-catalyzed three-component dicarbofunctionalization of unactivated alkenes with alkyl halides and Grignard reagents

A highly chemoselective iron-catalyzed three-component dicarbofunctionalization of unactivated olefins with alkyl halides (iodides and bromides) and sp2-hybridized Grignard reagents is reported. The reaction operates under fast turnover frequency and tolerates a diverse range of sp2-hybridized nucleophiles (electron-rich and electron-deficient (hetero)aryl and alkenyl Grignard reagents), alkyl halides (tertiary alkyl iodides/bromides and perfluorinated bromides), and unactivated olefins bearing diverse functional groups including tethered alkenes, ethers, protected alcohols, aldehydes, and amines to yield the desired 1,2-alkylarylated products with high regiocontrol. Further, we demonstrate that this protocol is amenable for the synthesis of new (hetero)carbocycles including tetrahydrofurans and pyrrolidines via a three-component radical cascade cyclization/arylation that forges three new C-C bonds.

Catalytic Allylation of Aldehydes Using Unactivated Alkenes

Simple feedstock organic molecules, especially alkenes, are attractive starting materials in organic synthesis because of their wide availability. Direct utilization of such bulk, inert organic molecules for practical and selective chemical reactions, however, remains limited. Herein, we developed a ternary hybrid catalyst system comprising a photoredox catalyst, a hydrogen-atom-transfer catalyst, and a chromium complex catalyst, enabling catalytic allylation of aldehydes with simple alkenes, including feedstock lower alkenes. The reaction proceeded under visible-light irradiation at room temperature and with high functional group tolerance. The reaction was extended to an asymmetric variant by employing a chiral chromium complex catalyst.

Developments in Photoredox/Nickel Dual-Catalyzed 1,2-Difunctionalizations

Progress in Ni/photoredox dual catalysis has enabled the construction of C(sp3)-hybridized centers under extremely mild reaction conditions in the presence of diverse functional groups. These strategies, however, are mainly restricted to the assembly of one C-C or C-heteroatom linkage because of the competitive two-component reactions and facile β-hydride elimination from alkylmetal complexes. Recently, photoinduced nickel-catalyzed 1,2-difunctionalizations of alkenes and alkynes have attracted extensive research efforts as they allow the construction of two sequential chemical bonds from inexpensive starting materials in one pot. Herein, we explore recent advances, state the current challenges, and discuss perspectives on the design of new catalytic systems.

Regioselective Arylboration of 1,3-Butadiene

A method for the regioselective 1,2-arylboration of 1,3-butadiene, a feedstock chemical, is reported. The reactions result in the formation of products that can be easily elaborated to other structures. The mechanistic details of this process are also discussed.

Nickel-Catalyzed Enantioconvergent Reductive Hydroalkylation of Olefins with α-Heteroatom Phosphorus or Sulfur Alkyl Electrophiles

Substantial advances in enantioconvergent C(sp³)-C(sp³) bond formation reactions have been made in recent years through the use of transition-metal-catalyzed cross-coupling reactions of racemic secondary alkyl electrophiles with organometallic reagents. Herein, we report a general process for the asymmetric construction of alkyl-alkyl bonds adjacent to heteroatoms, namely, a nickel-catalyzed enantioconvergent reductive hydroalkylation of olefins with α-heteroatom phosphorus or sulfur alkyl electrophiles. Including the use of readily available olefins, this reaction has considerable advantages, such as mild reaction conditions, a broad substrate scope, and good functional group compatibility, making it a desirable alternative to traditional electrophile-nucleophile cross-coupling reactions.

Cu-Catalyzed Asymmetric Aminoboration of E-Vinylarenes with pivZPhos as the Ligand

A Cu-catalyzed enantioselective aminoboration of E-vinylarenes with ^pivZPhos as a ligand is reported. Enantioenriched aminoborates are prepared with excellent regio- and enantioselectivities up to >99:1 er under the optimized conditions. The utility of the current method was further established by rapid conversion of an adduct to a chiral benzo[f][1,4]oxazepine. A model for the stereochemistry of the asymmetric aminoboration process, which agrees with the experimental outcomes, was generated by computational analysis of the systems.

Hemilabile Benzyl Ether Enables γ-C(sp3)-H Carbonylation and Olefination of Alcohols

Pd-catalyzed C(sp³)-H activation of alcohol typically shows β-selectivity due to the required distance between the chelating atom in the attached directing group and the targeted C-H bonds. Herein we report the design of a hemilabile directing group which exploits the chelation of a readily removable benzyl ether moiety to direct γ- or δ-C-H carbonylation and olefination of alcohols. The utility of this approach is also demonstrated in the late-stage C-H functionalization of β-estradiol to rapidly prepare desired analogues that required multi-step syntheses with classical methods.

Nickel-Catalyzed Arylboration of Alkenylarenes: Synthesis of Boron-Substituted Quaternary Carbons and Regiodivergent Reactions

A method for the construction of boron-substituted quaternary carbons or diarylquaternary carbons by arylboration of highly substituted alkenylarenes is presented. A wide range of alkenes and arylbromides can participate in this reaction thus allowing for a diverse assortment of products to be prepared. In addition, a solvent dependent regiodivergent arylboration of 1,2-disubstituted alkenylarenes is presented, thus greatly increasing the scope of products that can be accessed.

Palladium-Catalyzed Enantioselective Alkenylation of Enelactams Using a Relay Heck Strategy

In this report, a palladium-catalyzed redox-relay Heck process to access optically active alkenylated α,β-unsaturated lactams is described. Under mild reaction conditions, electron-deficient alkenyl triflates and electron-rich alkenyl iodonium salts undergo enantioselective and site-selective coupling with enelactams to deliver the products in high yields and excellent enantioselectivities. Furthermore, the products allow facile access to natural products such as (+)-calvine and (+)-2-epicalvine in addition to the bioactive molecule aza-goniothalamin.

Rh-Catalyzed Annulative Insertion of Terminal Olefin onto Pyridines via a C-H Activation Strategy Using Ethenesulfonyl Fluoride as Ethylene Provider

A Rh(III)-catalyzed annulative insertion of ethylene onto picolinamides was achieved, providing a portal to a class of unique pyridine-containing molecules bearing a terminal olefin moiety for diversification. Application of this method for modification of Sorafenib was also accomplished.

Nickel-Catalyzed 1,2-Arylboration of Vinylarenes

A novel nickel-catalyzed 1,2-arylboration of vinylarenes is reported. A variety of 2-boryl-1,1-diarylalkanes, which constitute a class of significant pharmacophores, are efficiently prepared from readily available olefins and aryl halides in the presence of bis(pinacolato)diboron under mild reaction conditions. The success of this three-component cascade is mainly attributed to the redox-active nitrogen-based ligand. Moreover, this method exhibits good functional group tolerance and excellent chemo- and stereoselectivity.