Isothiourea-Catalyzed Enantioselective α-Alkylation of Esters via 1,6-Conjugate Addition to para-Quinone Methides
作者:Jude N. Arokianathar、Will C. Hartley、Calum McLaughlin、Mark D. Greenhalgh、Darren Stead、Sean Ng、Alexandra M. Z. Slawin、Andrew D. Smith
DOI:10.3390/molecules26216333
日期:——
initial N-acylation of the isothiourea by the para-nitrophenyl ester, is proposed to facilitate catalyst turnover in this transformation. A range of para-nitrophenyl ester products can be isolated, or derivatized in situ by addition of benzylamine to give amides at up to 99% yield. Although low diastereocontrol is observed, the diastereoisomeric ester products are separable and formed with high enantiocontrol
报道了异硫脲催化对硝基苯酯与 2,6-二取代对醌甲基化物的对映选择性 1,6-共轭加成反应。对硝基酚盐是由对硝基苯酯对异硫脲进行初始N-酰化而原位生成的,被认为可以促进该转化中的催化剂周转。可以分离一系列对硝基苯酯产品,或通过添加苄胺原位衍生化,得到酰胺,收率高达 99%。尽管观察到低非对映控制,但非对映异构酯产物是可分离的,并以高对映控制(高达 94:6 er)形成。