Catalytic asymmetric synthesis of protected tryptophan regioisomers

PR Carlier, PCH Lam, DM Wong

Index: Carlier, Paul R.; Lam, Polo C.-H.; Wong, Dawn M. Journal of Organic Chemistry, 2002 , vol. 67, # 17 p. 6256 - 6259

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Citation Number: 24

Abstract

Tryptophan 1 (Trp) is superior to all other naturally occurring peptide residues in its ability to bind cations (the cation-π interaction). In an effort to expand the toolbox of Trp-like amino acids, in this note we report catalytic asymmetric syntheses of Trp regioisomers 2a-e, where the alanine unit is attached not to C-3 of indole but to C-2, C-4, C-5, C-6, or C-7. Excellent asymmetric induction is obtained in each case (generally> 97% ee). Ab initio calculations ...