Enantioselective Friedel-Crafts Alkylation of Furans and Indoles with Simple α,β-Unsaturated Ketones Catalyzed by Oxazaborolidinone
作者:Toshiro Harada、Shinya Adachi、Fumi Tanaka、Kazuya Watanabe、Atsushi Watada
DOI:10.1055/s-0029-1218821
日期:2010.8
allo-Threonine-derived oxazaborolidinone (OXB) catalyzes the Friedel-Crafts alkylation of furans and indoles with simple acyclic α,β-unsaturated ketones to give the products in high yields and with high enantioselectivities. With 5-10 mol% of the OXB catalyst, enantioselectivities of up to 94% ee could be achieved for a variety of substrates. The use of N,N-dimethylaniline (2.5-10 mol%) as an additive
同种异体-苏氨衍生oxazaborolidinone(OXB)催化呋喃和吲哚用简单的无环α,β不饱和酮的弗瑞德-克莱福特烷基化,得到产物以高产率和高对映选择性。使用5-10 mol%的OXB催化剂,对于多种底物,可以实现高达94%ee的对映选择性。已发现使用N,N-二甲基苯胺(2.5-10mol%)作为添加剂对于对映选择性是必不可少的。根据质子催化的外消旋途径的阻滞讨论了添加剂的作用,这阻碍了Friedel-Crafts反应的对映选择性。 不对称催化-烯酮-Friedel-Crafts反应-呋喃-吲哚