Spiropyrrolidine Catalyzed Asymmetric Cyclopropanation Of ?,?-unsaturated Aldehyde

In the past several decades, cyclopropanation reaction especially the asymmetric counterpart had proceed tremendous breakthrough. Among various catalysts to realize asymmetric alkene cyclopropanation, organocatalysts played as a kind of special catalysts had proved to be extraordinary in both catalyzing and stereoscopic controling. As one kind of privileged organocatalytic, prolinol silyl ether had acquired up to 96% ee and 2.7:1 dr in asymmetric cyclopropanation of ?,?-unsaturated aldehyde. In order to improve the poor result of prolinol silyl ether in diastereoselectivity, a new kind of secondary amine silyl ether “spiropyrrolidine” which was designed and synthesise by our group that had proved to be effective was tested. In asymmetry cyclopropane of ?,?-unsaturated aldehyde we have achieved up to 99% ee and 20:1 dr, and we had also confirmed the absolute configuration of product by XRD. The main content include two parts: 1. We had made a brief introduction in asymmetric cyclopropanation reaction in chapter one. Through the brief review in asymmetric cyclopropanation reaction in last two decades, we had simply introduced four kinds of methods that couud achieve chiral cyclopropane structure, and general summery their features. 2. We had made a brief introduction in organocatayzed asymmetric cyclopropanation reaction in chapter two. In order to improve the poor result of prolinol silyl ether in diastereoselectivity, we used a new kind of secondary amine silyl ether “spiropyrrolidine” which was designed and synthesise by our grohup. After reaction condition screen, we had achieved the asymmetric cyclopropane structure in good result. In addition,we had also confirm the absolute configuration of product by XRD.