Axially chiral catalysts for the preparation of optically active poly(triphenylmethyl methacrylate)

A variety of axially dissymmetric diphenylylene diamines 1a — 1f were synthesized and evaluated as chiral auxiliaries for the polymerization of triphenylmethyl methacrylate with organolithium compounds such as butyllithium and lithium (±)‐ N ‐(1‐phenylethyl)anilide in toluene at −78°C. The catalysts containing an optically active biphenylylene derivative of tetramethyl‐ethylenediamine ( 1e ) were found to be particularly useful for the preparation of optically active poly(triphenylmethyl methacrylate) (PTrMA). The catalysts afforded tetrahydrofuran (THF)‐soluble polymers in high yields and the polymers showed large optical rotations arising from a one‐handed helical conformation of a polymer chain. (+)‐ and (‐)‐PTrMAs were obtained by using ( S )‐ 1e and ( R )‐ 1e , respectively. The poly(methyl methacrylate)s derived from these PTrMAs were almost completely isotactic, but showed negligible optical rotations. The other catalysts produced mainly polymers insoluble in organic solvents; the small amounts of THF‐soluble materials showed rather low optical rotations.