Intramolecular cyclisation of enamide derivatives

Abstract

This thesis studied acid-induced intramolecular cyclisation of Boc-enamides containing [beta] and [gamma] dialkyl acetal group. The cyclisation of Boc-enamides containing [beta] dialkyl acetal group yielded N-substituted oxazolidin-2-one derivative in good yield. The cyclisation was proposed to undergo a nucleophilic attack on the acid activated acetal carbon by an oxygen atom on the Boc carbonyl. The cyclisation Boc-enamides containing [gamma] dialkyl acetal group gave pyridine derivative in low yield. The reaction presumably occurred through an attack of carbon atom of the alkene in enamide with an assist of decarboxylation in the Boc deprotection process. The cyclisation to form oxazolidin-2-ones was also extended successfully to Boc-amides.