Asymmetric Isothiourea-Catalysed Formal [3+2] Cycloadditions of Ammonium Enolates with Oxaziridines
作者:Siobhan R. Smith、Charlene Fallan、James E. Taylor、Ross McLennan、David S. B. Daniels、Louis C. Morrill、Alexandra M. Z. Slawin、Andrew D. Smith
DOI:10.1002/chem.201501271
日期:2015.7.13
A highly enantioselective Lewis base‐catalysed formal [3+2] cycloaddition of ammonium enolates and oxaziridines to give stereodefined oxazolidin‐4‐ones in high yield is described. Employing an enantioenriched oxaziridine in this process leads to a matched/mis‐matched effect with the isothiourea catalyst and allowed the synthesis of either syn‐ or anti‐stereodefined oxazolidin‐4‐ones in high d.r., yield
描述了一种高度对映选择性的路易斯碱催化的烯醇铵和恶氮丙啶的形式 [3+2] 环加成,以高收率得到立体定义的恶唑烷-4-酮。在该过程中使用富含对映体的恶氮丙啶导致与异硫脲催化剂的匹配/错配效应,并允许以高 dr、产率和ee合成顺式或反立体定义的恶唑烷-4-酮。此外,恶唑烷-4-酮产品已被衍生化,以提供功能化的对映体富集结构单元。