Asymmetric synthesis of chromanone lactones via vinylogous conjugate addition of butenolide to 2-ester chromones

Yi Li; Shuang Xin; Rui Weng; Xiaohua Liu; Xiaoming Feng

doi:10.1039/d2sc02541h

Asymmetric synthesis of chromanone lactones via vinylogous conjugate addition of butenolide to 2-ester chromones

Chem Sci. 2022 Jul 5;13(30):8871-8875. doi: 10.1039/d2sc02541h. eCollection 2022 Aug 4.

Authors

Yi Li¹, Shuang Xin¹, Rui Weng¹, Xiaohua Liu¹, Xiaoming Feng¹

Affiliation

¹ Key Laboratory of Green Chemistry & Technology, Ministry of Education, College of Chemistry, Sichuan University Chengdu 610064 China liuxh@scu.edu.cn xmfeng@scu.edu.cn.

Abstract

Chiral chromanone lactones are a class of natural products with important biological activity. We report a direct diastereo- and enantioselective vinylogous conjugate addition of butenolide to 2-ester substituted chromones. The transformation proceeded well in the presence of as low as 1 mol% of a chiral N,N'-dioxide/Sc^III complex, 3 Å MS and a catalytic amount of hexafluoroisopropanol (HFIP). The scope of Michael acceptors includes a variety of substituted chromones at different positions, and the desired chromanone lactones upon reduction are afforded in good yield and diastereoselectivity, and excellent enantioselectivity (up to 99% ee). The strategy could be used in the concise synthesis of blennolide C and gonytolide A, C and G.