Enantioselective Synthesis of 1,3-Benzothiazine Derivatives: An Organocatalytic Chemoselective Approach
作者:Prasenjit Gayen、Prasanta Ghorai
DOI:10.1021/acs.orglett.3c01120
日期:2023.6.2
Herein, a highly chemoselective 1,2-addition of thiols with 2-isothiocyanatochalcones followed by an enantioselective intramolecular thia-Michael addition cascade has been established to construct enantioenriched [1,3]-benzothiazine derivatives for the first time. The cinchona-derived squaramide catalyst provides good to excellent yield and enantioselectivity of the products with broad substrate adaptability
在此,首次建立了硫醇与 2-异硫氰基查耳酮的高度化学选择性 1,2-加成,然后是对映选择性分子内硫-迈克尔加成级联,以构建对映体富集的 [1,3]-苯并噻嗪衍生物。金鸡纳衍生的 squaramide 催化剂提供了良好的产品收率和对映选择性,具有广泛的底物适应性。此外,该策略已扩展到二苯基氧化膦亲核试剂,以获得富含对映体的有机磷取代的 [1,3]-苯并噻嗪。放大反应和合成转化证明了该协议的可行性。