Synthesis and Characterization of Optically Active Hyperbranched Poly(carbosiloxane)s

Abstract

An optically pure (S,S)-1,5-di(1-naphthyl)-1,5-diphenyl-1,5-divinyl-3-methyltrisiloxane (>99% ee) was synthesized by the condensation of (S)-lithium (1-naphthyl)phenylvinylsilanolate (>99% ee) with methyldichlorosilane. Hydrosilylation polymerization reactions with various feed ratios of (S,S)-1,5-di(1-naphthyl)-1,5-diphenyl-1,5-divinyl-3-methyltrisiloxane (AB2 monomer, A = Si−H and B = Vi) and 1,1,3,3-tetramethyl-1-vinyldisiloxane (A‘B‘ monomer) gave optically active hyperbranched poly(carbosiloxane)s in good yield (Mn = 4320−9370, [a]D25 = +13.1 to +4.5, Tg = −29−34 °C). Determinations of the composition and degree of branching (0.27−0.43) of the polymers were made by taking advantage of the simplicity of the 29Si NMR spectra of the optically active polymers compared with meso/dl polymers. End functionalization of the terminal vinyl groups (Vi) was demonstrated by using either hydrosilylation or hydroboration reactions, affording optically active hyperbranched poly(carbosiloxane)s having silyl chloride (Si−Cl) or hydroxy groups.