Synthesis of Multisubstituted Olefins through Regio- and Stereoselective Silylborylation of an Alkynylboronate/Chemoselective Cross-Coupling Sequences

A highly regio- and stereoselective silylborylation of an alkynylboronate is disclosed. PhMe₂Si–B_pin undergoes a Pd(OAc)₂/^<i>t</i>OctNC-catalyzed <i>syn</i>-addition to the alkynylboronate to yield 1-phenyl-1-silyl-2,2-diborylethene with high regioselectivity. The product 1-phenyl-1-silyl-2,2-diborylethene is then chemoselectively arylated by Suzuki–Miyaura coupling to afford (<i>Z</i>)-1-silyl-2-borylstilbene derivatives. This approach is extended to the synthesis of a tetraarylated olefin with four different substituents