We report the successful generation of (diborylmethyl)zinc(II) species by transmetallation beteween isolable (diborylmethyl)lithium and zinc(II) halide (X=Br, Cl) and their application in the synthesis of enantioenriched gem-diborylalkanes bearing a stereogenic center at the β-position of the diboryl groups by an asymmetric allylic substitution reaction. The reaction has a broad substrate scope, and various enantioenriched gem-diborylalkanes can be obtained in good yields with excellent enantioselectivity. Further elaboration of the enantioenriched gem-diborylalkanes provides access to a diverse set of valuable chiral building blocks.

The development of new approaches to installing diverse carbon fragments to a nitrogen atom has attracted considerable attention in chemical science. While numerous strategies have been devised to forge C(sp3)−N bonds, one conceptually powerful and straightforward approach is to insert a transformable sp3‐carbon unit onto a nitrogen atom for modular diversification. Here we describe the successful synthesis of halo‐diborylmethanes and their applications to the preparation of nitrogen‐substituted diborylmethanes through their homologative coupling with a variety of nitrogen nucleophiles including biologically relevant molecules. This process exhibits a remarkably broad substrate scope, and the usefulness of the obtained compounds is demonstrated by the modular diversification of the diborylmethyl group to access various nitrogen‐containing molecules.

We have developed a highly chemo- and diastereoselective alkylation of N-tert-butanesulfinyl aldimines with diborylmethane. Whereas the addition of diborylmethane under metal-free conditions shows poor diastereoselectivity, the use of a copper catalyst and a bidentate phosphine ligand significantly enhances the diastereoselectivity, providing chiral β-aminoboronates in good yields. On the basis of the stereochemical outcome, we propose that the reaction likely proceeds via a boron-chelating six-membered chairlike transition state.

We describe a palladium-catalyzed chemoselective Negishi cross-coupling of a bis­[(pinacolato)­boryl]­methylzinc halide with aryl (pseudo)­halides. This reaction affords an array of benzylic 1,1-diboronate esters, which can serve as useful synthetic handles for further transformations. The developed coupling reaction is compatible with various functional groups and can be easily scaled up. The coupling of bis­[(pinacolato)­boryl]­methyl­zinc halides with pharmaceuticals and the subsequent late-stage manipulations demonstrate the power of the developed protocol.

We report a highly chemo- and stereoselective crotylation of aldehydes and cyclic aldimines with allylic-gem-diboronate ester as a new type of organoboron reagent. The allylic-gem-diboronate ester undergoes the crotylation with aldehydes and cyclic aldimines in excellent stereoselectivity, forming anti-5,6-disubstituted oxaborinin-2-ols or (E)-δ-boryl-anti-homoallylic amines in high efficiency. The reaction shows a wide range of substrate scope and excellent functional group tolerance. The synthetic applications of the obtained products, including stereospecific C-C, C-O, and C-Cl bond formation, are also demonstrated.