Enantioselective Synthesis of Tricyclic β-Lactones by NHC-Catalyzed Desymmetrization of Cyclic 1,3-Diketones
作者:Sayan Shee、Subrata Mukherjee、Rajesh G. Gonnade、Akkattu T. Biju
DOI:10.1021/acs.orglett.0c01756
日期:2020.7.17
The NHC-catalyzed desymmetrization of cyclic-1,3-diketones allowing the enantioselective construction of tricyclic β-lactones with five contiguous stereocenters, including two quaternary stereocenters, has been developed. The mild and operationally simple addition of α-bromoenals to cyclopentane-1,3-diketone derivatives proceeds via the initial formation of chiral α,β-unsaturated acylazolium intermediates
已开发出NHC催化的1,3-二酮环的不对称化,可实现具有五个连续立体中心(包括两个四级立体中心)的三环β-内酯的对映选择性结构。向环戊烷-1,3-二酮衍生物中温和且简单地添加α-溴烯醛是通过手性α,β-不饱和酰基la中间体的初步形成而进行的,并最终在级联反应中达到顶峰,遵循迈克尔-醛醇内酯化途径β-内酯衍生物具有中等至良好的收率和优异的选择性。