Enantioselective Synthesis of α-Quaternary Amino Acid Derivatives by Sequential Enzymatic Desymmetrization and Curtius Rearrangement of α,α-Disubstituted Malonate Diesters
作者:Violeta Iosub、Anton R. Haberl、Jennifer Leung、Michael Tang、Kannan Vembaiyan、Masood Parvez、Thomas G. Back
DOI:10.1021/jo902584r
日期:2010.3.5
A convenient and versatile enantioselective synthesis of biologically important α-quaternary amino acid derivatives was based on the sequential double alkylation or arylation of dimethyl malonate, followed by desymmetrization with porcine liver esterase (PLE) and Curtius rearrangement. The PLE-mediated hydrolysis of the prochiral dialkylated malonate diesters produced the corresponding chiral half-esters
生物学上重要的α-季氨基酸衍生物的方便且通用的对映选择性合成是基于丙二酸二甲酯的顺序双烷基化或芳基化,然后用猪肝酯酶(PLE)进行不对称化和Curtius重排。PLE介导的前手性二烷基丙二酸二酯的水解以高收率和对映体过量43%至> 98%产生了相应的手性半酯。在用苄醇或胺捕获中间异氰酸酯后,后一种产物的库尔修斯重排得到相应的Cbz-保护的氨基酯或脲。在五个示例中,主要产品的绝对构型是通过转化为具有已知比旋光度的化合物确定的,