AlCl₃-Catalyzed Hydrosilylation of Alkynes with Hydropolysilanes

AlCl3 catalyzes addition reactions of hydrooligosilanes (H(SiMe2)nR; n = 2−4, R = H, Me, Ph) with 1-decyne and other alkynes under mild conditions. In most reactions the Si−Si bonds remain intact to form anticipated products in fair to excellent yields, although Si−Ph bonds appear to be cleaved partially under the conditions. Arylethynes tend to form abnormal products due to Si−Si bond scission, but at a low temperature, the addition reaction proceeds normally. The reaction of 1,2-dihydrotetramethyldisilane with 1-decyne furnishes 1,2-didecenyldisilane, 1,3-didecenyltrisilane, and other byproducts at 0 °C, while the reaction run at a lower temperature proceeds cleanly. 1,3-Dihydrohexamethyltrisilane reacts more cleanly even at 0 °C. The reaction of pentamethyldisilane with 1,6-heptadiyne proceeds in a different direction, leading to cyclization. 1,7-Octadiyne reacts with 1,3-dihydrohexamethyltrisilane to give a polymeric material. The reaction of 1,2,3-trihydropentamethyltrisilane or poly(phenylsilylene) with 1-dectyne proceeds cleanly without perceptible Si−Si bond cleavage.