Pd-catalyzed regio- and stereoselective addition of boronic acids to silylacetylenes: a stereodivergent assembly of β,β-disubstituted alkenylsilanes and alkenyl halides.

An efficient Pd-catalyzed addition of boronic acids to silylacetylenes is described, providing β,β-disubstituted (E)- or (Z)-alkenylsilanes in satisfactory yields with excellent regio- and stereoselectivity under mild reaction conditions. It represents the first highly regio- and stereoselective addition of boronic acids to aryl and alkenyl silylacetylenes. Moreover, the sequential Pd-catalyzed boron addition/N-halosuccinimide-mediated halodesilylation reaction results in a stereodivergent approach to β,β-disubstituted alkenyl halides, which can serve as versatile synthetic intermediates for the stereodivergent assembly of (E)- and (Z)-trisubstituted alkenes via transition-metal-catalyzed cross-coupling reactions.