Viso Alma, Férnandez de la Pradilla Roberto, Garciá Ana, Guerro-Strachan Carlos, Alonso Marta, Tortosa Mariola, Flores Aida, Martínez-Ripoll Martín, Fonseca Isabel, André Isabelle, Rodríguez Ana
Instituto de Química Orgánica, CSIC, Madrid, Spain.
Chemistry. 2003 Jun 16;9(12):2867-76. doi: 10.1002/chem.200204674.
A new procedure for the asymmetric synthesis of imidazolidines and vicinal diamines is reported. The 1,3-dipolar cycloaddition between nonracemic p-tolylsulfinimines and azomethine ylides generated in situ from alpha-iminoesters and LDA produces N-sulfinylimidazolidines with a high degree of stereocontrol. In contrast, the presence of Lewis acids promotes formation of the cycloadducts through a highly diastereoselective process with opposite stereochemistry. Subsequent transformations of the imidazolidines including oxidative, reductive, and hydrolytic processes that provide easy access to vicinal diaminoalcohols have been explored. Among these, reductive cleavage of the aminal with LiAlH4 is an extremely efficient and general reaction for the synthesis of enantiopure N-sulfinyl-N'-benzyldiaminoalcohols
报道了一种用于咪唑烷和邻二胺不对称合成的新方法。非外消旋对甲苯基亚磺酰亚胺与由α-亚氨基酯和LDA原位生成的甲亚胺叶立德之间的1,3-偶极环加成反应可产生具有高度立体控制的N-亚磺酰基咪唑烷。相比之下，路易斯酸的存在通过具有相反立体化学的高度非对映选择性过程促进环加成产物的形成。已经探索了咪唑烷的后续转化，包括氧化、还原和水解过程，这些过程可方便地获得邻二氨基醇。其中，用LiAlH4对缩醛胺进行还原裂解是合成对映体纯的N-亚磺酰基-N'-苄基二氨基醇的极其有效且通用的反应。
