Regio‐ and Diastereoselective [3+2] Annulation of Aliphatic Aldimines with Alkenes by Scandium‐Catalyzed β‐C(sp3)−H Activation. (27th December 2021)

• Record Type: Journal Article
• Authors: Cong, Xuefeng; Zhuo, Qingde; Hao, Na; Mo, Zhenbo; Zhan, Gu; Nishiura, Masayoshi; Hou, Zhaomin
• Is Part Of: Angewandte Chemie. Volume 134:Number 7(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2021-12-27
• Subjects: Aliphatic aldimine -- Aminocyclopentane -- [3+2] Annulation -- C(sp3)−H activation -- Scandium; Chemistry -- Periodicals; 540
• DOI: 10.1002/ange.202115996
• Languages: English
• ISSNs: 0044-8249

Abstract

Abstract: Here we report for the first time the regio‐ and diastereoselective [3+2] annulation of a wide range of aliphatic aldimines with alkenes via the activation of an unactivated β‐C(sp 3 )−H bond by half‐sandwich scandium catalysts. This protocol offers a straightforward and atom‐efficient route for the synthesis of a new family of multi‐substituted aminocyclopentane derivatives from easily accessible aliphatic aldimines and alkenes. The annulation of aldimines with styrenes exclusively afforded the 5‐aryl‐ trans ‐substituted 1‐aminocyclopentane derivatives with excellent diastereoselectivity through the 2, 1‐insertion of a styrene unit. The annulation of aldimines with aliphatic alkenes selectively gave the 4‐alkyl‐ trans ‐substituted 1‐aminocyclopentane products in a 1, 2‐insertion fashion. A catalytic amount of an appropriate amine such as adamantylamine (AdNH2 ) or dibenzylamine (Bn2 NH) showed significant effects on the catalyst activity and stereoselectivity. Abstract : Half‐sandwich scandium catalysts serve as a unique platform for the regio‐ and diastereoselective [3+2] annulation of aliphatic aldimines with alkenes via β−C(sp 3 )−H activation, affording a new family of multi‐substituted aminocyclopentane derivatives from easily accessible aldimines and alkenes with broad substrate scope, high regio‐, diastereoselectivity and 100 % atom‐efficiency.