6 Borylation of Carbonyl and Imine Groups

Abstract

AbstractThe nucleophilic borylation of carbonyl groups and imines provides α-oxy and α-amino boronate esters, respectively, under a variety of metal-catalyzed and metal-free reaction conditions. The resulting boronate esters, which can be accessed in high enantiopurity, have been utilized in a variety of transformations based on the reactivity of the carbon–boron bond. For α-oxy boronate esters, the oxygen or boron is often protected for increased stability. Formation of carbon–carbon bonds by homologation reactions and Suzuki–Miyaura-type coupling reactions provides advanced intermediates in synthesis. A variety of methods have been developed for the asymmetric synthesis of α-amino boronate esters, a key precursor to the α-amino boronic acid pharmacophore. Application of these methods to the synthesis of bortezomib and a precursor to (R)-cetirizine have been demonstrated.