X=Y-ZH compounds as potential 1,3-dipoles. Part 24. Preparation and thermal fragmentation of imidazolidines. Influence of metal salts on pyrrolidine versus imidazolidine formation
作者:Kitti Amornraksa、Darrin Barr、Gregory Donegan、Ronald Grigg、Piniti Ratananukul、Visuvanthar Sridharan
DOI:10.1016/s0040-4020(01)89100-6
日期:——
Imines of diethyl aminomalonate slowly dimerise imidazolidines in ethanol or methylene chloride at 40°C, but cycloaddition to other imines does not occur. Imines of glycine, alanine and phenylglycine methyl esters undergo rapid regio- and stereo-specific cycloaddition to methyl acrylate (MeCN, 25°C) in the presence of Ag(I) or Mn(II) salts, and triethylamine, whilst Zn(II)-or Co(II) salts dimerise
氨基丙二酸二乙酯的亚胺在40°C的乙醇或二氯甲烷中缓慢地使咪唑烷二聚,但不会发生与其他亚胺的环加成反应。甘氨酸,丙氨酸和苯基甘氨酸甲酯的亚胺在Ag(I)或Mn(II)盐和三乙胺的存在下,快速和立体特异性地环加成丙烯酸甲酯(MeCN,25°C) )或Co(II)盐将亚胺二聚为咪唑烷。在后一种情况下,还会发生向其他亚胺的环加成反应。Mg(II)盐的使用可能会导致吡咯烷或咪唑烷,具体取决于所使用的盐。注意到与金属阳离子水合焓的相关性。在双极性亲和剂的存在下加热咪唑烷类会导致串联的环还原-环加成过程,从而导致新的环加合物。