Efficient construction of polycyclic chromans through 4-methylbenzenesulfonic acid mediated domino 1,6-addition/oxa-Mannich reaction of ortho-hydroxyphenyl substituted para-quinone methides and cyclic enamides

摘要

A practical TsOH promoted novel domino 1,6-addition/oxa-Mannich reaction of cyclic enamides and ortho-hydroxyphenyl substituted para-quinone methides was established smoothly under mild reaction conditions. With this developed protocol, sorts of polycyclic compounds with chroman motifs were obtained in high level of yields and moderate to excellent diastereoselectivities (up to >99% yield, >20:1 dr). (C) 2019 Elsevier Ltd. All rights reserved.