Polystyrene-Supported (<i>R</i>)-2-Piperazino-1,1,2-triphenylethanol:  A Readily Available Supported Ligand with Unparalleled Catalytic Activity and Enantioselectivity

Abstract

A very active and highly enantioselective catalytic resin, designed for minimal perturbation of the catalytic center by the polymer matrix, has been assembled in two steps from (S)-triphenylethylene oxide, piperazine, and Merrifield resin and tested in the enantioselective ethylation of aldehydes. 1-Arylpropanols of 94-95% ee are obtained in high yield by the use of only 2 mol % of catalytic resin at 0 degrees C for 4 h.