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We report herein a modular catalytic method for the efficient enantioselective synthesis of chiral allylboronates from abundant feedstock chemicals through an asymmetric 1,1-difunctionalization of alkenes. This protocol is distinguished by its use of an inexpensive chiral catalyst, mild and convenient reaction conditions, wide substrate scope, scalability and practicality. The utility of this method is demonstrated by the rapid synthesis of key intermediates of complex drug molecules. Mechanistic studies reveal that β-H elimination is a highly regioselective step and the reversible homolysis and convergance to the lower energy pre-reductive elimination intermediate is the enantio-determining step., (© 2022 Wiley-VCH GmbH.)

Palladium-catalyzed oxidative amination of unactivated alkyl olefins has been developed to produce linear (E)-allylimides with high regioselectivity. This highly efficient transformation of alkenes has been achieved by enhancing the reoxidation of palladium with the strong oxidant PhI(OPiv)(2). The present work also provides the first systematic analysis of the mechanism of the allylic C-H oxidative amination. It has been found that naphthoquinone (NQ) plays a vital role in promoting olefin coordination to the palladium catalyst: in the absence of NQ, the turnover-limiting step is olefin coordination to palladium catalyst; in the presence of NQ, the reaction involves a rapid equilibration to give a nitrogen-coordinated olefin-Pd(NQ) complex that undergoes turnover-limiting allylic C-H bond activation to generate a pi-allyl-Pd intermediate. This work provides valuable insights for further studies on the functionalization of unactivated olefins.

A novel palladium-catalyzed intramolecular oxidative aminofluorination of unactivated alkenes has been developed, in which AgF was used as a key fluorinating reagent and PhI(OPiv)(2) as oxidant. The reaction afforded vicinal fluoroamine products with very high regioselectivity. A Pd(II/IV) catalytic cycle was proposed, and preliminary mechanistic studies indicated that direct reductive elimination of Pd(IV) intermediates is favored, albeit competing with S(N)2 nucleophilic attack by fluorine, to form a C-F bond.

Comprehensive Summary: The synthesis of N‐glycosides has received significant attention due to their crucial role in carbohydrate chemistry. Despite considerable advancements developed in the construction of N‐glycosides, methods for the stereoselective construction of 2‐deoxy‐α‐N‐glycosides are still limited. Herein, we disclosed a nickel‐catalyzed hydroamination of glycals under mild conditions. This transformation could allow for the stereoselective synthesis of an array of 2‐deoxy‐α‐N‐glycosides with excellent α‐stereoselectivity. Nickel‐catalyzed glycosylation reactions, particularly those involving anomeric C(sp3)‐metal bond formation, have proven to be an effective and stereoselective strategy for producing various N‐glycosides. Additionally, with highlight of the application of this reaction, γ‐sugar amino acid derivatives were synthesized. [ABSTRACT FROM AUTHOR]

Organosilicon compounds have shown tremendous potential in drug discovery and their synthesis stimulates wide interest. Multicomponent cross-coupling of alkenes with silicon reagents is used to yield complex silicon-containing compounds from readily accessible feedstock chemicals but the reaction with simple alkenes remains challenging. Here, we report a regioselective silylalkylation of simple alkenes, which is enabled by using a stable Ni(II) salt and an inexpensive trans−1,2-diaminocyclohexane ligand as a catalyst. Remarkably, this reaction can tolerate a broad range of olefins bearing various functional groups, including alcohol, ester, amides and ethers, thus it allows for the efficient and selective assembly of a diverse range of bifunctional organosilicon building blocks from terminal alkenes, alkyl halides and the Suginome reagent. Moreover, an expedient synthetic route toward alpha-Lipoic acid has been developed by this methodology. Multicomponent cross-coupling of alkenes with silicon reagents is used to yield complex silicon-containing compounds from readily accessible feedstock chemicals but the reaction with simple alkenes remains challenging. Here, the authors report a regioselective silylalkylation of simple alkenes, which is enabled by using a stable Ni(II) salt and an inexpensive trans-1,2-diaminocyclohexane ligand as a catalyst. [ABSTRACT FROM AUTHOR]

While chain‐walking stimulates wide interest in both polymerization and organic synthesis, site‐ and stereoselective control of chain‐walking on rings is still a challenging task in the realm of organometallic catalysis. Inspired by a controllable chain‐walking on cyclohexane rings in olefin polymerization, we have developed a set of chain‐walking carboborations of cyclohexenes based on nickel catalysis. Different from the 1,4‐trans‐selectivity disclosed in polymer science, a high level of 1,3‐regio‐ and cis‐stereoselectivity is obtained in our reactions. Mechanistically, we discovery that the base affects the reduction ability of B2pin2 and different bases lead to different catalytic cycles and different regioselective products (1,2‐ Vs 1,3‐addition). This study provides a concise and modular method for the synthesis of 1,3‐disubstituted cyclohexylboron compounds. The incorporation of a readily modifiable boronate group greatly enhances the value of this method, the synthetic potential of which was highlighted by the synthesis of a series of high‐valued commercial chemicals and pharmaceutically interesting molecules. [ABSTRACT FROM AUTHOR]

We report herein a modular catalytic method for the efficient enantioselective synthesis of chiral allylboronates from abundant feedstock chemicals through an asymmetric 1,1‐difunctionalization of alkenes. This protocol is distinguished by its use of an inexpensive chiral catalyst, mild and convenient reaction conditions, wide substrate scope, scalability and practicality. The utility of this method is demonstrated by the rapid synthesis of key intermediates of complex drug molecules. Mechanistic studies reveal that β‐H elimination is a highly regioselective step and the reversible homolysis and convergance to the lower energy pre‐reductive elimination intermediate is the enantio‐determining step. [ABSTRACT FROM AUTHOR]

The direct difunctionalization of alkenes, a cheap and abundant feedstock, represents one of the most attractive strategies for increasing molecular complexity in synthetic organic chemistry. In contrast with the 1,2‐difunctionalization of alkenes, recent advances showcase alkene 1,n‐difunctionalizations (n≠2) involving metal migration is an emerging and rapidly growing area of research. This promising strategy not only opens a novel avenue for future development of alkene transformations, but also significantly expands upon the bond disconnections available in modern organic synthesis. This Minireview summarizes recent progress in the migratory difunctionalization of alkenes, with an emphasis on the driving force for metal migration. [ABSTRACT FROM AUTHOR]

An unprecedented nickel-catalyzed 1, n -arylboration (n >2) of terminal nonactivated alkenes has been developed. This reaction is the first example of a regioselective arylboration of terminal nonactivated alkenes and features high selectivity, wide functional-group tolerance, and operational simplicity. Remarkably, preliminary mechanistic studies indicated that an equilibrium of various nickel intermediates exists in this transformation, but bond formation is favored at the benzylic position. [ABSTRACT FROM AUTHOR]

An unprecedented nickel‐catalyzed 1,1‐alkylboration of electronically unbiased alkenes has been developed, providing straightforward access to secondary aliphatic boronic esters from readily available materials under very mild reaction conditions. The regioselectivity of this reaction is governed by a unique pyridyl carboxamide ligated catalyst, rather than the substrates. Moreover, this transformation shows excellent chemo‐ and regio‐selectivity and remarkably good functional‐group tolerance. We also demonstrate that under balloon pressure, ethylene can also be utilized as a substrate. Additionally, competence experiments indicate that selective bond formation is favored at the α‐position of boron and preliminary mechanistic studies indicate that the key step in this three‐component reaction involves a 1,2‐nickel migration. [ABSTRACT FROM AUTHOR]

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Comprehensive Summary Chiral 1,3‐substituted fragments are ubiquitous in pharmaceutical molecules and natural products, prompting the development of numerous methods to access these structures. Nonetheless, devising synthetic routes for complex chiral architectures in practical applications typically demands years of expertise. Herein, we developed a nickel‐catalyzed enantioselective migratory arylboration reaction of allylboronic esters using a chiral 1,2‐diamine ligand, yielding a range of chiral 1,3‐bis(boronates) with high enantioselectivity. The protocol is characterized by its use of commercially available substrates, mild reaction conditions, user‐friendly procedures, and a broad substrate compatibility. Moreover, we demonstrate the practicality and application potential of this reaction by synthesizing several key drug intermediates. [ABSTRACT FROM AUTHOR]

Review: 67 refs. [ABSTRACT FROM AUTHOR]

[Display omitted] While 1,2-regioselective difunctionalizations of alkenes are well developed, their migratory difunctionalization of alkenes remains comparatively under-researched. Herein, we report a nickel-catalyzed, divergent, solvent-controlled 1,1- or 1,3-regioselective benzylboration of allylbenzenes, that provides efficient access to primary and secondary alkyl boronates. The mild reaction conditions of these transformations allow good regioselectivity and wide functional group tolerance. [ABSTRACT FROM AUTHOR]

[Display omitted] Synthesis of organosilanes from alkenes is a very important topic owing to their wide applications. A Ni/Cu dual metal-catalyzed arylsilylation of terminal alkenes, featuring migratory selectivity, has been developed. A wide diversity of aliphatic silanes have been prepared from terminal alkenes, aryl halides and Suginome's reagent. This protocol is highlighted by excellent regioselectivity, mild reaction conditions and good functional group tolerance. In addition to benzylic positions, carbon–carbon bonds can also be constructed at allylic positions. Preliminary mechanistic studies suggest that the copper cocatalyst promotes the transmetalation of Suginome's reagent, and the addition of a PyrOx ligand inhibits the formation of side-products from the carbon-Heck pathway. Moreover, studies toward the nature of the PyrOx ligand revealed that the steric hindrance of the oxazoline moiety greatly affects the chain–walking process, but not the arylation step. [ABSTRACT FROM AUTHOR]