Intramolecular nitrene insertions into aromatic and hetero-aromatic systems. Part I. Insertion into naphthalenes and tetralins

Abstract

Thermal decomposition of 1- and of 2-(2-azidobenzyl)naphthalenes gives, by nitrene insertion, mixtures of benz[a]-acridan (10) and benz[a]acridine (13), and of benz[c]acridan (21) and benz[c]acridine (22) respectively. Decomposition of 5-(2-azidobenzyl)tetralin (29) gives predominantly the tetrahydroindolo[2,1-a][2]benzazepines (31) and (34), and the tetrahydroindolo[1,2-a][1]benzazepine (32); 6-(2-azidobenzyl)tetralin (25) gives the tetrahydroindolo[1,2-b][2]benzazepine (26). Minor products from the decomposition of 1-(2-azidobenzyl)-naphthalene were indolobenzazepines; minor products from the tetralins were tetrahydro- and hexahydro-benzacridines. The reasons for these contrasting insertion pathways are discussed.