Reactions of carbodi-imides with toluene-p-sulphonyl azide in the presence of copper or pentacarbonyliron

Abstract

Reactions of carbodi-imides (1a–d) with toluene-p-sulphonyl azide in the presence of copper powder afforded guanidines (3a–d). Reactions with pentacarbonyliron instead of copper powder also gave the guanidines (3). These reactions are thought to proceed by initial formation of an azide–metal complex and/or a nitrene–metal complex, followed by insertion of the carbodi-imides into a metal–nitrogen bond. When the reactions were carried out in pyridine in the absence of metal, a tetrazole (11) and N-pyridiniotoluene-p-sulphonamidate were the major products.