A Spiroalkylation Method for the Stereoselective Construction of α-Quaternary Carbons and Its Application to the Total Synthesis of (<i>R</i>)-Puraquinonic Acid
作者:Adam A. H. Elmehriki、James L. Gleason
DOI:10.1021/acs.orglett.9b03887
日期:2019.12.6
Cyclic α-quaternary carbon stereocenters were prepared from biselectrophillic substrates and an easily prepared chiral bicyclic sulfonyl lactam. This was achieved in two steps by spiroalkylation, employing biphasic reaction conditions with a phase-transfer catalyst, followed by reduction and alkylation with a series of alkyl halide electrophiles. The products of this method were isolated in good yields
由双亲电子底物和易于制备的手性双环磺酰基内酰胺制备环状α-季碳立体中心。这是通过螺烷基化在两个步骤中实现的,采用相转移催化剂采用两相反应条件,然后通过一系列卤代烷基亲电试剂进行还原和烷基化。该方法的产物以高收率和高非对映选择性被分离出来。该方法用于(R)-嘌呤奎尼酸(1)的对映选择性全合成,用于α-季碳立体中心的后期安装。这使得迄今为止最短的1合成过程成为可能,即一个8罐序列,总产率为14%。