Regio- and Chemoselective Diboration of Allenes with Unsymmetrical Diboron: Formation of Vinyl and Allyl Boronic Acid Derivatives

A platinum-catalyzed terminal diboration of 1,1-disubstituted allenes using a differentially protected diboron is described. Diboration occurs in a regio- and chemoselective fashion to furnish vinyl and allyl boronates in good to excellent yield and selectivity. Transformation of the bis-boronyl products to other functional groups as well as in chemoselective cross-coupling is demonstrated.