Access to Enantioenriched Spiro‐ϵ‐Lactam Oxindoles by an N‐Heterocyclic Carbene‐Catalyzed [4+3] Annulation of Flexible Oxotryptamines with Enals. Issue 48 (1st August 2019)

• Record Type: Journal Article
• Authors: Liu, Dehai; Hu, Zhouli; Zhang, Yuxia; Gong, Minghua; Fu, Zhenqian; Huang, Wei
• Is Part Of: Chemistry. Volume 25:Issue 48(2019)
• Page Start: 11223
• Page End: 11227
• Publication Date: 2019-08-01
• Subjects: [4+3] annulation -- flexible oxotryptamines -- N-heterocyclic carbenes -- organocatalysis -- spiro-ϵ-lactam oxindoles; Chemistry -- Periodicals; 540
• DOI: 10.1002/chem.201903144
• Languages: English
• ISSNs: 0947-6539

Abstract

Abstract: Oxotryptamines were firstly used as flexible four‐atom synthons in an NHC‐catalyzed formal [4+3] annulation, providing a novel enantioselective method to access structurally diverse spiro‐ ϵ ‐lactam oxindoles with excellent enantioselectivities. This metal‐free reaction features a broad substrate scope, excellent functional‐group tolerance and proceeds under mild reaction conditions. Importantly, enantiopure privileged hexahydropyrroloindoles could be easily constructed by a one‐pot process from the resulting spiro‐ ϵ ‐lactam oxindoles. Abstract : Organocatalysis : Oxotryptamine was used as a flexible four‐atom synthon in an NHC‐catalyzed formal [4+3] annulation, providing an enantioselective method to access structurally diverse spiro‐ ϵ ‐lactam oxindoles with excellent enantioselectivities. This metal‐free reaction features a broad substrate scope, excellent functional‐group tolerance and proceeds under mild reaction conditions (see scheme).