α,β-Unsaturated esters bearing a chiral oxazolidine or perhydropyrrolo[1,2-c]imidazole auxiliary at the β-position have been prepared and applied to the cycloadditions with N-metalated azomethine ylides derived from α-(benzylideneamino) esters. These reactions are found to proceed with an exclusively high diastereofacial selectivity to give 2,4-pyrrolidinedicarboxylates with four consecutive chiral
Asymmetric 1,3-dipolar cycloadditions of azomethine ylides with a chiral electron-deficient olefinic dipolarophile
作者:Kanemasa Shuji、Yamamoto Hidetoshi
DOI:10.1016/s0040-4039(00)94463-0
日期:1990.1
The first example of efficient asymmetric 1,3-dipolarcycloadditions of azomethine ylides is presented, where reactive N-metalated azomethine ylides and the α,β-unsaturatedester with a chiral perhydropyrrolo[1,2—c]imidazol-3-yl moiety at the β-position have been employed. The exclusive participation of thermodynamically less stable 3-H/3′-H synperiplanar conformer is based on its sterical preference
给出了高效有效的不对称1,3-偶极偶氮甲亚胺环加成反应的第一个例子,其中反应性N-金属化的偶氮甲亚胺和具有手性过氢吡咯并[1,2 - c ]咪唑-3-基的α,β-不饱和酯在β-位已被采用。热力学不稳定的3-H / 3'-H上平面共形异构体的排他性参与是基于其在边界轨道和螯合控制的刚性游离态中的空间偏好。