期刊
ACS CATALYSIS
卷 13, 期 14, 页码 9495-9501出版社
AMER CHEMICAL SOC
DOI: 10.1021/acscatal.3c01961
关键词
Friedel-Crafts reaction; phenol; sulfonylaldimine; asymmetric catalyst; regioselective; nickel; strontium
The conventional acid-catalyzed aza-Friedel-Crafts reaction of phenols with imines typically shows ortho-selectivity. However, a chiral bis(imidazolidine) pyridine (PyBidine)-Ni(OAc)(2) catalyst can switch the regioselectivity to para-selectivity. This switch is facilitated by the bulky PyBidine-Ni(OAc)(2) catalyst with a Ph2CHCH2 substituent, resulting in highly para-selective aza-Friedel-Crafts reactions (up to 99:1 para/ortho selectivity).
The conventional acid-catalyzed aza-Friedel-Craftsreactionof phenols with imines typically proceeds in an ortho-selective manner. A chiral bis(imidazolidine) pyridine (PyBidine)-Ni(OAc)(2) catalyst switches the regioselectivity to para-selectivity. By replacement of the benzyl substituent of the parentPyBidine with a bulky Ph2CHCH2 substituent,the bulky PyBidine-Ni(OAc)(2) catalyst enabledhighly para-selective aza-Friedel-Crafts reactions(up to 99:1 para/ortho selectivity).With the assistance of a Sr(OAc)(2) additive, a wide rangeof 3,5-dialkoxyphenols with sulfonylaldimines gave para-substituted products with up to 93% ee. DFT calculations suggestthat the cooperative activation from nickel phenoxide formation (HOMOactivation) and the hydrogen bonding activation of the sulfonylaldimine(LUMO activation) is the key for switching the regioselectivity.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据