The Norrish type II reaction of thiophthalimides having a benzylic hydrogen in an N-alkyl side chain.

Abstract

Upon irradiation, thiophthalimides (4 and 5) possessing an N-ω-phenylalkyl substituent undergo the Norrish type II cyclization to give tricyclic isoindole derivatives (6-8).In the case of thiophthalimides (11) possessing an indene in the N-side chain, two competitive pathways, the Norrish type II and a Paterno-Buchi like type, were observed.