A highly straightforward route to enantiomerically highly enriched cis-2,3-dihydrobenzofurans has been achieved via addition of α-diazocarbonyl compounds to in situ generated o-QMs catalyzed by a chiral Brønsted acid. This catalytic strategy provides a direct access to 2,3-dihydrobenzofurans in high yields and with up to 91:9 dr and 99:1 er at ambient temperature. Moreover, a unique phenonium-type
通过将α-重氮羰基化合物加到由手性布朗斯台德酸催化的原位生成的o- QMs中,已经获得了一种对映异构体高度浓缩的顺式-
2,3-二氢苯并呋喃的非常直接的途径。这种催化策略可直接获得高收率的2,3二氢
苯并呋喃,在环境温度下可达91:9 dr和99:1 er。此外,独特的型重排可解释具有反向2,3取代模式的产物形成。