Thermal [2+3]-Cycloadditions of trans-1-Methyl-2,3-diphenylaziridine with CS and CC Dipolarophiles: An Unexpected Course with Dimethyl Dicyanofumarate
作者:Grzegorz MlostonÌ、Katarzyna Urbaniak、MaÅgorzata DomagaÅa、Arno Pfitzner、Manfred Zabel、Heinz Heimgartner
DOI:10.1002/hlca.200900236
日期:2009.12
orbital‐symmetry‐controlled reactions (Scheme 2). On the other hand, the reactions of cis‐1a and trans‐1a with dimethyl dicyanofumarate (7a), as well as that of cis‐1a and dimethyl dicyanomaleate (7b), led to mixtures of the same two stereoisomeric dimethyl 3,4‐dicyano‐1‐methyl‐2,5‐diphenylpyrrolidine‐3,4‐dicarboxylates 8a and 8b (Scheme 3). This result has to be explained via a stepwise reaction mechanism, in which
的热反应的反式-1-甲基-2,3- diphenylaziridine(反式- 1A与芳族和脂环族硫酮)2在沸腾的甲苯,得到相应的顺式-2,4-二苯基-1,3-噻唑烷的顺式- 4 经由conrotatory的开环反式- 1A和中间的一致[2 + 3] -环(ê,ê)构型的偶氮甲碱内鎓盐3a中(方案1)。cis ‐ 1a与乙炔二甲酸二甲酯的类似反应(5),得到二甲基反式-2,5-二氢-1-甲基-2,5-二苯基吡咯-3,4-二羧酸二乙酯(反式- 6与轨道对称控制的反应一致)(方案2)。在另一方面,的反应顺式- 1A和反式- 1A与二甲dicyanofumarate(图7a),以及其的顺式- 1A和二甲基dicyanomaleate(图7b),导致了同样的两种立体异构二甲酯的混合物3,4-二氰基-1-甲基-2,5-二苯基吡咯烷-3,4-二羧酸酯8a和8b(方案3)。该结果必须通过逐步反应机理来解