Asymmetric Reactions. II. Asymmetric Synthesis of Methyl α-Phenylpropionate by Means of Chiral Polymers

Abstract

Abstract The asymmetric addition of methanol to phenylmethylketene was carried out in the presence of propionylcinchonine and poly(acryloylcinchonine). The use of poly(acryloylcinchonine) produced additional products with higher optical yields than that of propionylcinchonine. The highest optical yield (35%) was obtained with the above polymeric catalyst at −78 °C. An insoluble, cross-linked polymer obtained by the co-polymerization of acryloylcinchonine with N,N′-diacryloylhexamethylenediamine, was also used as a catalyst. The products obtained for the cross-linked polymer showed a linear correlation between logkR/ks and 1/T while those with non-cross-linked poly(acryloylcinchonine) exhibited a relationship deviating somewhat from linearity. A linear relationship was also observed using insoluble, cross-linked poly(acryloylquinine).