Polymerization of Cyclododecasiloxanes with Si–H and Si–OEt Side Groups by the Piers-Rubinsztajn Reaction

Abstract

Abstract Two types of cyclododecasiloxanes possessing Si–H and Si–OEt side groups were polymerized by the Piers-Rubinsztajn (P-R) reaction. Cyclododecasiloxane possessing both methyl and ethoxydimethylsilyl side groups (Cyclo12-Me-SiMe2(OEt)) was synthesized by ethoxylation of cyclododecasiloxane possessing both methyl and dimethylsilyl side groups (Cyclo12-Me-SiHMe2). Cyclo12-Me-SiMe2(OEt) and Cyclo12-Me-SiHMe2 were polymerized by the P-R reaction, using B(C6F5)3 as a catalyst. The original cyclic structures were retained after the reaction without cleavage of the Si–O–Si bonds. Dimethylsilane elimination between two side –SiHMe2 groups and the consecutive siloxane-bond formation occurred concomitantly during the main P-R reaction. The effectiveness of the P-R reaction between oligosiloxanes toward preparation of polyorganosiloxanes with well-defined architectures has been demonstrated.