Benzomorphan-related compounds. Part 21. Synthesis of 7,8-benzomorphans via 2-aryl-4-piperidones

Abstract
A new synthesis of 1,2,3,4,5,6-hexahydro-1,5-methano-2-benzazocines (7,8-benzomorphans) based on the acid-catalysed cyclization of 2-arylpiperidine-4-carboxylic acids is reported. The required carboxylic acids were prepared from 2-aryl-4-piperidones, by reaction with tosylmethyl isocyanide followed by hydrolysis of the resulting 4-cyanopiperidines.