Photocyclization of 2-Indolylalkyl N-Chloroacetamides1,2

Abstract
Since the original observation by Witkop and coworkers that N-chloroacetyl β-phenethylamines undergo photocyclization to yield benzazepines,3 utility of this reaction for the synthesis of benzazepine,4–7 benzazocine,8–9 benzazonine,8 isoquinoline,10 azocinoindole,11 and naphthazocine12 derivatives has been explored with moderate success. Notable among these is the formation of an azocinoindole (lactam of L-tryptophan-4-acetic acid) from N-chloroacetyl-L-tryptophan which represents the only example of an indole N-chloroacetamide which has been subjected to photolysis.11