Copper-Catalyzed Electrophilic Amination of <i>gem</i>-Diborylalkanes with Hydroxylamines Providing α-Aminoboronic Acid Derivatives

Abstract

A copper-catalyzed electrophilic amination of gem-diborylalkanes with hydroxylamines has been developed. The key to its success is the use of the Me3Si-modified 1,2-bis(diphenylphosphino)benzene ligand. Additionally, the reactivity of neopentylglycol derivatives compared to that of commonly used pinacol-derived ones is found to be higher, particularly in the case of relatively sterically congested substrates. The copper catalysis presented here enables the first successful catalytic carbon–heteroatom bond forming reaction of gem-diborylalkanes to form the corresponding α-aminoboronic acid derivatives, which are of great interest in medicinal and pharmaceutical chemistry.