Regioselective Formation of 5-Methylene-6-methoxy-1,4,5,6-tetrahydropyridazines from the [4+2]-Cycloaddition Reaction of In Situ Generated 1,2-Diaza-1,3-dienes with Methoxyallene

Abstract

A regioselective inverse-electron-demand hetero-Diels–­Alder reaction of in situ generated 1,2-diaza-1,3-dienes with methoxyallene is reported. These Lewis and Brønsted acid free reactions benefit from operational simplicity and allow access to synthetically valuable 5-methylene-6-methoxy-1,4,5,6-tetrahydropyridazines in high yields.