Chemoselective Synthesis of Substituted Benzoxazines and Imidazolidines by Reactions of Hydroxyl Substituted Ethylenediamine Derivatives with Aldehydes

Abstract

Lewis acid La(OTf) 3 -catalyzed chemoselective cyclization of hydroxyl substituted ethylenediamine derivatives with aldehydes has been described for the first time, which provides efficient access to diversely functionalized 1,3-imidazolidines and 3,1-benzoxazines in generally good yields only by adjusting the position of the methylene group within hydroxyl substituted ethylenediamines. The reaction is suitable to aromatic aldehydes and aliphatic ones. Plausible mechanisms are also proposed to explain the observed reaction modes, wherein the nucleophilicity of nitrogen and oxygen atoms plays an important role in controlling the chemoselectivity.