Asymmetric alkylation of an α-keto ester with chiral lithium alkoxy-tributylaluminates

Lithium tetrabutylaluminate modified by either (-)-N-methylephedrine or Darvon alcohol[(*)-(2S, 3R)-4-dimethylamino-3-methyl-1,2-diphenyl-2-butanol] readily reacts with phenylglyoxylic acid methyl ester to give the expected α-butyl α-hydroxy ester with a good chemical yield and an optical yield of 43% when Darvon alcohol is used.