Design of Chiral Bifunctional Quaternary Phosphonium Bromide Catalysts Possessing an Amide Moiety

Novel bifunctional quaternary phosphonium bromides possessing an amide moiety were designed for the highly enantioselective sulfenylation and chlorination of β-ketoesters under base-free phase-transfer conditions. The tuning of an amide moiety of the catalyst was crucial to achieve high reactivity and enantioselectivity.研究人员设计了一类携有酰胺基团（amide moiety）的新型双功能季鏻溴盐（bifunctional quaternary phosphonium bromides），可用于无碱相转移催化条件下β-酮酯的高对映选择性亚磺酰化（sulfenylation）与氯化反应。对该催化剂的酰胺基团进行调控，是实现高反应活性与优异对映选择性的关键所在。