Palladium-catalyzed synthesis of novel optically active tryptophan analogues
van Esseveldt BCJ, van Delft FL, de Gelder R, Rutjes FPJT
ORGANIC LETTERS 5 (10): 1717-1720 MAY 15 2003

Abstract:
Both unsaturated proline derivatives and optically active tryptophan analogues have been obtained via Pd-catalyzed cyclization of aniline-containing acetylenic amino acids. The side chain length of the cyclization precursor determines which one of the two possible products will be formed.