The Synthesis of Pyrroles and Dihydropyrroles by 1,3-Dipolar Cyclisations of<i>N</i>-Arylmethylene[(benzotriazol-1-yl)arylmethyl]amines
作者:Alan R. Katritzky、Gregory J. Hitchings、Xiaohong Zhao
DOI:10.1055/s-1991-26595
日期:——
N-Arylmethylene[(benzotriazol-1-yl)arylmethyl]amines 1 are prepared by the reaction of arylaldehydes, benzotriazole, and ammonia in dry ethanol. Deprotonation of these imines with butyllithium yields N-lithiated azomethine ylides 2 which readily undergo 1,3-dipolar cycloaddition with a large range of dipolarophiles. The cyclisations are regiospecific and generally exhibit high stereoselectivity. Benzotriazolate is eliminated during the course of the reaction, and the method thereby provides a route to 2,5-diaryl substituted pyrroles, 3,4-dihydro-2H-pyrroles and c-ring fused 3,4-dihydro-2H-pyrroles.
N-芳烯基[(苯并三唑-1-基)芳基甲基]胺1是通过芳醛、苯并三唑和氨在无水乙醇中反应制备的。用丁基锂对这些亚胺进行去质子化,生成N-锂化的亚胺亚胺盐2,这些盐能够与多种双极体发生1,3-极性环加成反应。这些环化反应具有区域特异性,并且通常表现出高立体选择性。在反应过程中,苯并三唑盐被消除,从而提供了一条合成2,5-二芳基取代吡咯、3,4-二氢-2H-吡咯及c环融合的3,4-二氢-2H-吡咯的方法。