Simple and Efficient Synthesis of Racemic Substituted Mandelic Acid Esters from Nonactivated Arenes and Ethyl Glyoxylate

Abstract

Direct synthesis of racemic aromatic α-hydroxyacetic acid esters via Friedel-Crafts reaction of nonactivated, simple arenes with ethyl glyoxylate promoted by SnCl 4 or AlCl 3 is described. The use of SnCl 4 opens a fast access to various alkyl- and aryl-substituted mandelic acids esters at room temperature within two hours in good yield (>80%) and with high regioselectivity. The procedure was successfully employed also for the alkylation of compounds with condensed aromatic rings. Alternative hydroxyalkylations with AlCl 3 require longer reaction time and higher temperature to get a good yield.