10.1016/j.endend.2013.01.001

Abstract

The preparation of tryptophan derivatives through the Lewis acid promoted substitution of aziridine carboxylates with indole was found to be accompanied by a ring-expansion reaction to generate an oxazolidinone byproduct. The ratio of tryptophan to oxazolidinone products can be optimised through judicious choice of Lewis acid and N-protecting group.