Asymmetric epoxidation of α, β-unsaturated ketones via an amine-thiourea dual activation catalysis. (30th March 2021)

• Record Type: Journal Article
• Authors: Zhang, Lu-Wen; Wang, Li; Ji, Nan; Dai, Si-Yang; He, Wei
• Is Part Of: Tetrahedron letters. Volume 68(2021)
• Publication Date: 2021-03-30
• Subjects: Asymmetric epoxidation -- Chalcone -- Chiral amine-thiourea -- Organocatalyst; Chemistry, Organic -- Periodicals; 547.005
• DOI: 10.1016/j.tetlet.2021.152941
• Languages: English
• ISSNs: 0040-4039

Abstract

Graphical abstract: Highlights: A mild and simple asymmetric epoxidation reaction catalyzed by amine-thiourea was developed. A series of α -carbonyl epoxides were synthesized, 22 examples, up to 90% yield and 96% ee. A reasonable analysis of the reaction mechanism was carried out, and a possible transition state model was proposed. Abstract: A simple asymmetric epoxidation method is developed to effectively synthesize chiral α -carbonyl epoxides through an amine-thiourea dual activation catalysis. In this method, TBHP, as an oxidant, determined the reaction rate, and the chiral amine-thiourea catalyst effectively controlled the stereoselectivity of the reaction, and KOH promoted deprotonation. 22 examples of α, β -unsaturated ketones with various substituent groups are smoothly converted into α -carbonyl epoxides with moderate to excellent enantiomeric excess.