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
example of oxyamination of azlactones with oxaziridines was realized using a chiral bisguanidinium salt. Efficient catalytic asymmetric oxyamination and kinetic resolution of oxaziridines occurred simultaneously. Various chiral oxazolin-4-one derivatives with potential biological activity were obtained (up to 92% ee). Meanwhile, a series of optically pure oxaziridines were recovered with up to 99% ee and