Diastereoselective Synthesis of Unnatural Amino Acids by Alkylation of α-<i>tert</i>-Butanesulfinamide Auxiliary-Bound Enolates
作者:Natalie C. Dwulet、Tina A. Zolfaghari、Molly L. Brown、Jeffrey S. Cannon
DOI:10.1021/acs.joc.8b01379
日期:2018.10.5
auxiliary for the diastereoselective alkylation of amino ester enolates that takes advantage of chiral information stored on the enolate side of the amino ester substrate has been developed. Chiral α-sulfinamido esters were alkylated under basic conditions in good yields (up to 90%) and good to high diastereoselectivities (generally >6:1) to provide unnatural mono- and α,α-disubstituted amino acid derivatives
已经开发出一种用于氨基酯烯醇盐的非对映选择性烷基化的新手性助剂,其利用了存储在氨基酯底物的烯醇盐侧的手性信息的优势。手性α-亚磺酰胺基酯在碱性条件下以良好的收率(高达90%)和良好的非对映选择性(通常> 6:1)被烷基化,以提供非天然的单和α,α-二取代的氨基酸衍生物。这种助剂可以方便地将酯官能团转化,而无需使用深层试剂。此外,容易除去助剂以提供对映体纯的氨基酸。计算研究表明,螯合的过渡态决定了瞬态双环中间体凸面的亲电子加成。该方法允许随时获得对映体富集的天然和非天然氨基酸。