Synthesis and characterization of optically active hyperbranched poly(carbosiloxane)s

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 (AB(2) 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 (M-n = 4320-9370, [a](D)(25) = +13.1 to +4.5, T-g = -29-34 degreesC). 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 Si-29 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.