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Azole and azine heteroarenes were directly alkylated by alkanes, ethers, or carbamates using PhC(O)O2tBu under LED irradiation. 9,10-Dichloroanthrocene acted as an organic photocatalyst and transferred its excitation energy to PhC(O)O2tBu via exciplex formation.

Catalytic domino alkenylation–heteroarylation of nonconjugated iododienes proceeded with excellent stereoselectivity and broad scope of substrates.

Pd-catalyzed chemo- and regiocontrollable 1,1-diarylation of unactivated aliphatic alkenes with two aryl halides was developed. Under the cationic reductive-delay Heck pathway, the first aryl insertion is followed by β-H elimination, while the second aryl insertion is terminated by C-H bond formation.

This review summarizes the state-of-the-art in transition metal-catalyzed asymmetric alkylation of heteroarenes using alkenes (covering literature from 2000 to late 2021). Based on elementary reactions on metals for substrate activation, these reactions are broadly classified in several categories: (A) concerted oxidative addition of heteroaryl C-H bonds on rhodium(I) and iridium(I), (B) ligand-to-ligand hydrogen transfer (LLHT) on low-valent 3d metal complexes of nickel and cobalt, (C) different ways for deprotonation of heteroaryl C-H bonds by late transition metal complexes, especially palladium, including electrophilic aromatic substitution and a related mechanism, base-assisted intramolecular electrophilic substitution, concerted and nonconcerted metalation deprotonation, (D) σ-bond metathesis by d

A nickel-catalyzed intermolecular arylcyanation of 8-aminoquinolinyl β,γ-unsaturated amides is reported. The three-component reaction directly afforded diverse β-cyano γ-aryl amides with exclusive chemo- and regioselectivity. The synthetic practicality of this approach is further demonstrated through multigram scale reaction, expanded transformations of the nitrile product, late-stage modification of complex molecules, and direct drug synthesis.

Nickel-catalyzed intermolecular Heck reaction of cycloalkenes proceeds well with aryl triflates, mesylates and tosylates in excellent enantiomeric ratios. The asymmetric reductive Heck reaction also works with a 2-cyclopentenone ketal, which is equivalent to conjugate arylation of the enone itself. Economic Development Board (EDB) Accepted version We acknowledge financial supports from Peking University Shenzhen Graduate School, Shenzhen Bay Laboratory Insti- tute of Chemical Biology, Nanyang Technological University, GlaxoSmithKline and the Singapore Economic Development Board Trust Fund (2017 GSK-EDB Green and Sustainable Manufacturing Award) and A*STAR Science and Engineer- ing Research Council (A1783c0010).

Conformationally restricted azabicycles are becoming increasingly important in medicinal research. Asymmetric Heck bicyclization of enynes proceeds to give medicinally useful aza[3.1.0] and aza[4.1.0] bicycles with excellent enantioselectivity. The key organopalladium species after bicyclization can be trapped by silanes and terminal alkynes. Agency for Science, Technology and Research (A*STAR) Economic Development Board (EDB) Accepted version We acknowledge financial support from Peking UniversityShenzhen Graduate School, Shenzhen Bay Laboratory(21230011-Scripps), National Natural Science Foundation ofChina (NSFC 21933004), Nanyang Technological University,GSK-EDB Trust Fund (2017 GSK-EDB Green and Sustain-able Manufacturing Award) and A*STAR Science andEngineering Research Council (AME IRG A1783c0010).MP contributed DFT calculations.

Substituted cyclohexylamines are becoming increasingly important in drug discovery. Asymmetric Heck insertion/amination of nonconjugated cyclodienes proceeds to give 5-aryl cyclohexenylamines with good enantioselectivity and exclusive trans configurations. Primary and secondary anilines, indoline, and benzylamines are suitable amines. The weakly donating diphosphite Kelliphite forms a deep unsymmetrical pocket, which is essential for stereoselective anti attack of amines. Agency for Science, Technology and Research (A*STAR) Economic Development Board (EDB) Accepted version We acknowledge financial support from Peking UniversityShenzhen Graduate School, Shenzhen Bay Laboratory(21230011-Scripps), Nanyang Technological University,GSK-EDB Trust Fund (2017 GSK-EDB Green and Sustain-able Manufacturing Award) and A*STAR Science andEngineering Research Council (AME IRG A1783c0010).

A nickel complex of isoquinox promoted enantioselective conjugate arylation and heteroarylation of enones using aryl and heteroaryl halides directly. The reaction was successfully applied to stereoselective syntheses of ar-turmerone, chiral fragments of (+)-tolterodine and AZD5672. Mechanistically, experiments and calculations supported that an arylnickel(I) complex inserted to enones via an elementary 1,4-addition. National Research Foundation (NRF) We acknowledge financial support from Peking University Shenzhen Graduate School, State Key Laboratory of Chemical Oncogenomics, Guangdong Provincial Key Laboratory of Chemical Genomics, Shenzhen Bay Laboratory and Shanghai Key Laboratory for Molecular Engineering of Chiral Drugs for J.S.Z., the National Natural Science Foundation of China (NSFC 21933004) for Y.D.W., and Singapore National Research Foundation (NRF-CRP22-2019-0002) for Y.R.C.

We report a stereoselective conversion of terminal alkynes to α-chiral carboxylic acids using a nickel-catalyzed domino hydrocarboxylation-transfer hydrogenation reaction. A simple nickel/BenzP* catalyst displayed high activity in both steps of regioselective hydrocarboxylation of alkynes and subsequent asymmetric transfer hydrogenation. The reaction was successfully applied in enantioselective preparation of three nonsteroidal anti-inflammatory profens (>90 % ees) and the chiral fragment of AZD2716.

Nickel complexes ligated by strongly donating diphosphines catalyze enantioselective hydrogenation for the preparation of acyclic and cyclic β-amido esters. A combination of acetic acid and indium powder provides protons and electrons to form nickel hydrido complexes under umpolung hydrogenation conditions.

A simple catalyst of Ni(OAc)2 and P(t-Bu)3 enables selective C-alkylation of thioacetamides and primary acetamides with alcohols for the first time. Monoalkylation of thioamides, amides and t-butyl esters occurs in excellent yields (>95%). Mechanistic studies reveal that the reaction proceeds via a hydrogen autotransfer pathway.

A nickel-catalyzed reductive cyclization of enones affords a wide array of indanones in high enantiomeric induction. The reaction is featured with an unprecedented broad scope of substrates. The versatility of the new method is demonstrated in several short stereoselective syntheses of medically valuable (R)-tolterodine, parent and deuterated (+)-indatraline, and an antitumor natural product, (+)-multisianthol. In comparison, these compounds cannot be prepared satisfactorily via analogous processes catalyzed by palladium.

A nickel-catalyzed arylation of both aliphatic and aromatic aldehydes proceeds with air-stable (hetero)arylboronic acids, with an exceptionally wide substrate scope. The neutral condition tolerates acidic hydrogen and sensitive polar groups and also preserves α-stereocenters of some chiral aldehydes. Interestingly, this nickel(0) catalysis does not follow common 1,2-insertion of arylmetal species to aldehydes and β-hydrogen elimination.

Copper complexes of monodentate phosphoramidites efficiently promote asymmetric arylation of N-azaaryl aldimines with arylboroxines. DFT calculations and experiments support an elementary step of 1,4-insertion in the reaction pathway, a step in which an aryl-copper species adds directly across four atoms of C=N-C=N in the N-azaaryl aldimines. Agency for Science, Technology and Research (A*STAR) Nanyang Technological University We thank the Nanyang Technological University,GSK-EDBTrust Fund (GSK-EDB Green and Sustainable Manufactur-ing Award 2017), A*STAR Science &Engineering ResearchCouncil (AME IRG A1783c0010), City University of HongKong (7200534 and 9610369) and National Science Founda-tion of China (21502157) for financial support.

Nickel-catalyzed Heck reaction of cycloalkenes delivers unusual conjugated arylated isomers. Nickel(0) catalysts ligated by chelating dialkylphosphines effectively activate not only aryl triflates as electrophiles, but also less reactive aryl mesylates, tosylates and pivalates. The omission of bases allows nickel hydride species to exist long enough to perform in situ olefin isomerization of initial Heck adducts. Accepted version

Palladium catalyzes a domino Heck arylation and alkylation of nonconjugated cyclodienes to produce trans isomers of disubstituted cyclohexenes in exceptionally high enantiomeric ratios, reaching 100:1 to 200:1 in many cases. Importantly, the interactions of the two CF bonds of Josiphos and the sodium ion of malonates facilitates stereoselective allylic attack through DFT calculations and experiments. This is a new type of attractive noncovalent interactions found in organometallic catalysis. Economic Development Board (EDB) Nanyang Technological University We acknowledge financial support from Peking University Shenzhen Graduate School and Shenzhen Bay Laboratory for J.S.Z.; the National Natural Science Foundation of China (NSFC 21933004) for Y.-D.W.; Nanyang Technological University and GlaxoSmithKline and the Singapore Economic Development Board Trust Fund (2017 GSK-EDB Green & Sustainable Manufacturing Award) for Y.R.C.

Asymmetric coupling proceeds efficiently between propargylic acetates, cycloalkenes and electron-rich heteroarenes including indoles, pyrroles, activated furans and thiophenes. 2,3-Disubstituted tetrahydrofurans and pyrrolidines are produced in trans configuration and excellent enantiomeric ratios. The reaction proceeds via Wacker-type attack of nucleophilic heteroarenes on alkenes activated by allenyl PdII species. Agency for Science, Technology and Research (A*STAR) Economic Development Board (EDB) Accepted version We acknowledge financial support from Peking University Shenzhen Graduate School, Shenzhen Bay Laboratory Institute of Chemical biology, Nanyang Technological University, GSK-EDB Trust Fund (2017 GSK-EDB Green and Sustain- able Manufacturing Award) and A*STAR Science and Engineering Research Council (AME IRG A1783c0010).

A simple catalyst of Ni(OAc)2 and P(t-Bu)3 enables selective C-alkylation of thioacetamides and primary acetamides with alcohols for the first time. Monoalkylation of thioamides, amides and t-butyl esters occurs in excellent yields (95%). Mechanistic studies reveal that the reaction proceeds via a hydrogen autotransfer pathway.

Asymmetric reductive amination of poorly nucleophilic sulfonamides was realized in the presence of nickel catalysts and titanium alkoxide. A wide range of ketones, including enolizable ketones and some biaryl ones, were converted into sulfonamides in excellent enantiomeric excess. The cyclization of sulfamates and intermolecular reductive amination of a diarylphosphinamide were also successful. Formic acid was used as a safe and economic surrogate of high-pressure hydrogen gas. Agency for Science, Technology and Research (A*STAR) Economic Development Board (EDB) We thank Singapore GSK-EDB Trust Fund (2017 GSK-EDBgreen and sustainable manufacturing award) and SingaporeA*STAR Science &Engineering Research Council (AMEIRG A1783c0010) for financial support. We thank BenAshley for some initial experiments.X.Z. and H.X. contrib-uted equally to the experiments.

The palladium-catalyzed intermolecular Heck-type reaction of both cyclic and acyclic epoxides is reported with tolerance of typical polar groups and acidic protons. Suitable alkenes include styrenes, conjugate dienes, and some electron-deficient olefins. In reactions of aliphatic terminal epoxides, ring opening occurs selectively at terminal positions, and stereocenters of epoxides are fully retained. Mechanistic studies provide evidence for in situ conversion of epoxides to β-halohydrins, generation of alkyl radicals, and radical addition to alkenes as key steps. Cyclovoltammetric determination of reduction potentials suggests that during activation of alkyl iodides by palladium(0) complexes, inner-sphere halogen abstraction is more likely than outer-sphere single electron transfer. MOE (Min. of Education, S’pore)

Enantioselective α‐arylation of racemic ketones containing existing α′‐stereocenters is reported for the first time via base‐induced dynamic kinetic resolution. Bridged bicyclic rings are formed in good ee values, which are difficult to obtain otherwise. Furthermore, reactions in DMSO‐d6 resulted in extensive deuteration of both α‐ and α′‐positions in the products, thus supporting a pathway involving rapid, reversible deprotonation of ketones under catalytic conditions. MOE (Min. of Education, S’pore) Accepted version

Intermolecular alkylations of electron‐deficient arenes proceed with good para selectivity. Palladium catalysts were used to generate nucleophilic alkyl radicals from alkyl halides, which then directly add onto the arenes. The arene scope and the site of alkylation are opposite to those of classical Friedel–Crafts alkylations, which prefer electron‐rich systems. MOE (Min. of Education, S’pore) Accepted version

An asymmetric Heck annulation of propargylic acetates with several types of cyclic olefins affords highly strained cyclobutenes in high enantioselectivity.

A borrowing-hydrogen reaction between amines and alcohols is an atom-economic way to prepare alkylamines, ideally with water as the sole byproduct. Herein, nickel catalysts are used for direct N-alkylation of hydrazides and arylamines using racemic alcohols. Moreover, a nickel catalyst of (S)-binapine was used for an asymmetric N-alkylation of benzohydrazide with racemic benzylic alcohols.

A nickel‐catalyzed asymmetric reductive Heck reaction of aryl chlorides has been developed that affords substituted indolines with high enantioselectivity. Manganese powder is used as the terminal reductant with water as a proton source. Mechanistically, it is distinct from the palladium‐catalyzed process in that the nickel–carbon bond is converted into a C−H bond to release the product through protonation instead of hydride donation followed by C−H reductive elimination on Pd. MOE (Min. of Education, S’pore) Accepted version

Nickel-catalyzed asymmetric hydrogenation of several types of alkenes proceeds in high enantioselectivity, using acetic acid or water as the hydrogen source and indium powder as electron donor. The scope of alkenes herein include α,β-unsaturated esters, nitriles, and ketones as well as allylic alcohols. Asymmetric deuteration of α,β-unsaturated esters is also achieved with deuterated water, the cheapest deuterium source.

Palladium-catalyzed three-component carboetherification of cyclic alkenes proceeded to give trans adducts exclusively with excellent enantioselectivity through a Wacker-type pathway. The reaction is also applicable to other oxygen nucleophiles, such as water, phenols, and carboxylic acids, as well as some electron-poor aryl amines. Agency for Science, Technology and Research (A*STAR) Economic Development Board (EDB) Accepted version We acknowledge financial support from Peking University Shenzhen Graduate School, Shenzhen Bay Laboratory (21230011-Scripps), Nanyang Technological University, the GSK-EDB Trust Fund (2017 GSK-EDB Green and Sustainable Manufacturing Award), and A*STAR Science and Engineering Research Council (AMEIRGA1783c0010)..

A nickel-catalyzed reductive cyclization of enones affords a wide array of indanones in high enantiomeric induction. The reaction is featured with an unprecedented broad scope of substrates. The versatility of the new method is demonstrated in several short stereoselective syntheses of medically valuable (

The transition-metal-catalyzed α-arylation of carbonyl compounds is a widely practiced method for C–C bond formation. Several enantioselective versions of this process have been reported, but intermolecular, enantioselective coupling reactions of aryl electrophiles with α-fluoro carbonyl compounds have yet to be disclosed. We report enantioselective coupling of aryl and heteroaryl bromides and triflates with α-fluoroindanones catalyzed by palladium complexes of a BINOL-derived monophosphine and Segphos, respectively. The enolates were generated directly from α-fluoroindanones in the presence of potassium phosphate base during the reactions. We also report that reactions of α-fluorotetralones occur in high yields and enantioselectivities when conducted with enolates generated by elimination of trifluoroacetate from trifluoromethyl β-diketone hydrates. These reactions were catalyzed by palladium complexes of the commercially available bisphosphine Difluorphos. Thus, the formation of enantioenriched α-aryl-α-fluoroketones can be readily achieved by C–C bond formation when the appropriate palladium catalyst and α-fluoro enolate precursor were used. MOE (Min. of Education, S’pore) Accepted version

Palladium-catalyzed α-arylation reactions of ketones with simultaneous ortho alkylation offer 1,2,3-substituted arenes. The reactions of 1,ω-dihaloalkanes also allow facile construction of medicinally important tetralines and benzocycloheptenes. MOE (Min. of Education, S’pore) Accepted version

Asymmetric transfer hydrogenation of α,β-unsaturated esters is realized by using a nickel/bisphosphine catalyst and N,N-dimethylformamide (DMF) as the hydride source.

An asymmetric reductive amination of ketones using both arylamines and benzhydrazide in the presence of nickel catalysts was developed. A one-pot synthesis of tetrahydroquinoxalines was also developed starting directly from α-ketoaldehydes and 1,2-diaminobenzene. Formic acid was used as a safe and economic surrogate for high-pressure hydrogen gas. Strongly σ-donating bis(alkylphosphine)s are crucial ancillary ligands for both stereoselective hydride insertion and decarboxylation of the formate.

We report an efficient alkynylation reaction of aryl iodides with simultaneous ortho-alkylaton of aryl rings. The reaction between three simple reagents—aryl halides, alkynes, and alkyl halides—formed aryl–alkynyl bonds carrying hindered aryl rings in one step. The reaction proceeded via a Catellani-type pathway in the presence of norbornene. From a synthetic perspective, this reaction allows quick access toward many 1,2,3-substituted arenes and multiply substituted benzofurans, after manipulation of alkyne groups. These compounds are difficult to synthesize otherwise. MOE (Min. of Education, S’pore)

We report an efficient alkynylation reaction of aryl iodides with simultaneous ortho-alkylaton of aryl rings. The reaction between three simple reagents—aryl halides, alkynes, and alkyl halides—formed aryl–alkynyl bonds carrying hindered aryl rings in one step. The reaction proceeded via a Catellani-type pathway in the presence of norbornene. From a synthetic perspective, this reaction allows quick access toward many 1,2,3-substituted arenes and multiply substituted benzofurans, after manipulation of alkyne groups. These compounds are difficult to synthesize otherwise.

We report the use of nickel catalysts for the catalytic transfer hydrogenation of hydrazones and other ketimines with formic acid. Strongly donating bisphosphines must be used to support the catalysts. As in enzymatic catalysis, attractive weak interactions may be important for stereochemical control by the nickel/binapine catalyst.

A general alkylation of heterocycles using a simple palladium catalyst is reported. Most classes of heterocycles, including indoles and pyridines, efficiently coupled with unactivated secondary and tertiary alkyl halides. An alkyl radical addition to neutral heteroarenes is most likely involved.

A general procedure for the fast Suzuki coupling of major families of heteroaryl bromides was realized by using Pd(OAc)2/PtBu3 as the catalyst. Many couplings were finished within minutes at room temperature in n-butanol. Different from previous studies, three typical heteroaryl bromides were systematically examined in couplings of various heteroaryl and aryl boronic acids.

The addition of an N-H bond to an olefin is the most direct route for the synthesis of alkylamines. Currently, intermolecular hydroamination is limited to reactions of a narrow range of reagents containing N-H bonds or activated alkenes, and all the examples of additions to unactivated alkenes require large excesses of alkene. We report intermolecular hydroamination reactions of indoles with unactivated olefins. The reactions occur with as few as 1.5 equiv of olefin to form N-alkylindoles exclusively and in good yield. Characterizations of the catalyst resting state, kinetic data, labeling studies, and computational data imply that the addition occurs by olefin insertion into the Ir-N bond of an N-indolyl complex and that this insertion reaction is faster than insertion of olefin into the Ir-C bond of the isomeric C-2-indolyl complex.

Nickel-catalyzed addition of arylboron reagents to ketones results in aryl olefins directly. The neutral condition allows acidic protons of alcohols, phenols, and malonates to be present, and fragile structures are also tolerated. MOE (Min. of Education, S’pore) Accepted version

Asymmetric transfer hydrogenation of electron-deficient olefins is realized with nickel catalysts supported by strongly σ-donating bisphosphines. Deuterium labeling experiments point to a reaction sequence of formate decarboxylation, asymmetric hydride insertion and non-stereoselective protonation of resulting nickel enolates. Published version