A Highly Efficient and Selective Route to Isomeric Cyclic Diazadienes

摘要

We have reported a novel and selective Lewis acid-mediated ring expansion of methylenecyclopropyl hydrazones to cyclic dienamines and azadienes in good to excellent yields and in excellent selectivities. Additional studies have found that the choice of Lewis acid and ligand was key in selectively obtaining either the azadiene or dienamine products. Further exploration of the reaction scope and mechanistic studies to determine the origin of this highly unusual and reversal in selectivity are ongoing.