Anti-Selective Vicinal Silaboration and Diboration of Alkynoates through Phosphine Organocatalysis

Trialkylphosphine organocatalysts have enabled anti-selective vicinal silaboration and diboration of the C-C triple bond in alkynoates to produce beta-boryl-alpha-silyl acrylates and alpha,beta-diboryl acrylates, respectively. The anti stereoselectivity was complete and robust. A variety of functional groups were tolerated in the alkynoates. The two vicinally installed heteroatom substituents of the beta-boryl-alpha-silyl acrylates and alpha,beta-diboryl acrylates could be differentiated and transformed in a stepwise manner, allowing the synthesis of a diverse array of unsymmetrical tetrasubstituted alkenes.