Enzyme catalysed hydrolyses of dialkylated propanedioic acid diesters have been studied. A novel change of enantioselectivity from pro-S to pro-R in the hydrolysis of ester groups was observed, depending on the chain length of the alkyl substituents of the substrate. Optically pure (S)-(-)-α-methylphenylalanine was prepared by α-chymotrypsin catalysedhydrolysis of benzylmethylpropanedioic acid dimethyl
synthesis features a Catellani reaction/oxa‐Michael cascade for the construction of the isochroman scaffold, a one‐pot deprotection/spiroacetalization operation for the formation of the tetracyclic core structure, and a late‐stage Ni‐catalyzed reductive coupling for the introduction of the lateral chain. Notably, four stereocenters are established from a single existing chiral center with excellent stereocontrol
Eight-Step Asymmetric Synthesis of (–)-Berkelic Acid
作者:Hong-Gang Cheng、Qianghui Zhou、Zhenjie Yang、Ruiming Chen、Liming Cao、Qiang Wei、Qingqing Wang
DOI:10.1055/a-1799-0459
日期:2022.11
This work features a sequential Catellani-type reaction/oxa-Michael addition with epoxides as dual-functionalized alkylating reagents for synthesizing the isochroman framework, a one-pot, acid-catalyzed deprotection/spiroacetalization process for the construction of a tetracyclic core intermediate, and a late-stage Ni-catalyzed reductive coupling reaction for the installation of the side chain. Remarkably
我们在此报告了 (–)-berkelic 酸的八步不对称合成。这项工作的特点是连续 Catellani 型反应/oxa-Michael 加成与环氧化物作为双官能化烷基化试剂用于合成异色满框架,一锅酸催化脱保护/螺缩醛化过程用于构建四环核心中间体,以及用于安装侧链的后期 Ni 催化还原偶联反应。值得注意的是,在去保护/螺缩醛化过程中,从一个现有的手性中心创建了四个具有高立体控制的新立体中心。