Gold‐Catalyzed One‐Step Construction of 2,3‐Dihydro‐1<i>H</i>‐Pyrrolizines with an Electron‐Withdrawing group in the 5‐position: A Formal Synthesis of 7‐Methoxymitosene

Abstract

What a ring formation! Bicyclic dihydropyrrolizines with an electron-withdrawing group (EWG) at the 5-position are formed in one step from linear azidoenynes under gold catalysis. This novel route involves the use of azide as a nitrene precursor, electronically-controlled regioselectivity, and the generation of destabilized 1-azapentadienium ions and their pericyclic reactions. This method was used for a formal synthesis of 7-methoxymitosene.