Asymmetric Construction of Remote Vicinal Quaternary and Tertiary Stereocenters via Direct Doubly Vinylogous Michael Addition
作者:Subhrajit Rout、Harshit Joshi、Vinod K. Singh
DOI:10.1021/acs.orglett.8b00493
日期:2018.4.20
An asymmetric direct doubly vinylogous Michael addition has been developed for the generation of sterically congested vicinal quaternary and tertiary stereocenters. This doubly vinylogous Michael addition of β,γ-unsaturated butenolides to 3-methyl-4-nitro-5-alkenyl isoxazoles, powered by a bifunctional squaramide, affords a broad range of densely functionalized enantioenriched γ,γ-disubstituted butenolides
已经开发出不对称的直接双乙烯基迈克尔加成物,用于产生空间拥挤的邻近四元和三元立体中心。在双官能的方酰胺的作用下,β,γ-不饱和丁烯内酯的双乙烯基迈克尔加成反应到3-甲基-4-硝基-5-链烯基异恶唑上,可以高收率得到各种致密的对映体富集的γ,γ-二取代丁烯内酯,在大多数情况下,出色的非对映选择性和对映选择性。此外,该策略突出了在不对称的1,6-共轭加成中首次应用β,γ-不饱和丁烯内酯。