Cationic Palladium Complex-catalyzed Cyclization-Hydrosilylation of 1-Alkene-6,11-diyne Derivatives

A palladium complex, [(η3-C3H5)Pd(cod)]+[PF6]- (C), catalyzes hydrosilylation of 1-dodecene-6,11-diyne (5) or 1-tridecene-6,11-diyne (7), and of their 9-oxo congeners (9 or 11), with HSiCl3 to form regioisomeric cyclization products (6, 8, 10, and 12, respectively), which arise between the diyne part (path a) to form A series or between the enyne counterpart (path b) to form B series. The formation of product B is markedly favored with 1-tridecene-6,11-diyne derivatives as compared with 1-dodecene-6,11-diyne ones that possess a terminal alkyne.