A new method was developed for the first catalytic enantioselective borylation of aliphatic ketones. A variety of substrates reacted efficiently with bis(pinacolato)diboron in the presence of a copper(I)/chiral N-heterocyclic carbene complex catalyst to furnish optically active tertiary α-hydroxyboronates with moderate to high enantioselectivities (up to 94 % ee). Notably, the product could be converted into the chiral tertiary alcohol derivative using a stereospecific boron functionalization process. The theoretical study of the mechanism for the enantioselectivity is also described.

The catalytic enantioselective nucleophilic borylation of ketimines is reported. A series of acyclic dialkyl ketimines reacted efficiently with bis(pinacolato)diboron in the presence of a copper(I)/chiral N-heterocyclic carbene catalytic system to furnish optically active α-amino tertiary boronates with high enantioselectivity (up to 99% ee). The products can be converted into peptidylboronic acid derivatives that bear bulky aliphatic substituents, compounds that are difficult to synthesize by other methods. Density functional theory calculations indicated that the enantioselectivity-determining step involves noncovalent interactions that recognize the prochiral dialkyl ketimine, leading to highly efficient enantiodiscrimination.

A new method was developed for synthesizing 2-alkyl-2-boryl-tetrahydrofuran derivatives from aliphatic ketones using a copper(i)/N-heterocyclic carbene complex catalyst.