Organocatalytic and enantioselective [4+2] cyclization between hydroxymaleimides and <i>ortho</i>-hydroxyphenyl <i>para</i>-quinone methide-selective preparation of chiral hemiketals
Min Xiang, Chenyi Li, Xiang‐Jia Song, Ying Zou, Zhicheng Huang, Xia Li, Fang Tian, Li-Xin Wang
Abstract
A cinchona alkaloid squaramide promoted enantioselective [4+2] cyclization between hydroxymaleimides and ortho-hydroxyphenyl p-QMs has been disclosed, and a wide range of chiral hemiketals containing chromane and succinimide frameworks with two adjacent quaternary stereogenic centers have been prepared for the first time with excellent results (up to 99% yield, up to 99 : 1 dr, up to >99% ee) under mild conditions.
Topics & Concepts
Enantioselective synthesisChemistryQuinone methideQuinoneSuccinimideCombinatorial chemistryCinchonaStereochemistryOrganic chemistryCatalysisSynthesis of Indole DerivativesAxial and Atropisomeric Chirality SynthesisBioactive Compounds and Antitumor Agents