Highly enantioselective synthesis of (R)-alpha-alkylserines via phase-transfer catalytic alkylation of o-biphenyl-2-oxazoline-4-carboxylic acid tert-butyl ester using Cinchona-derived catalysts

摘要

A highly enantioselective synthetic method for (R)-alpha-alkylserines was developed by the phase-transfer catalytic alkylation of o-biphenyl-2oxazoline-4-carboxylic acid tert-butyl ester (4i) using cinchona-derived phase-transfer catalyst N(1)-(9-anthracenylmethyl)-O(9)-allyi-dihydrocinchonidinium bromide (up to 96% ee).