Collective formal synthesis of (±)-rhynchophylline and homologues. Issue 68 (1st July 2016)

• Record Type: Journal Article
• Authors: Xu, Jun; Shao, Li-Dong; Shi, Xin; Ren, Jian; Xia, Chengfeng; Zhao, Qin-Shi
• Is Part Of: RSC advances. Volume 6:Issue 68(2016)
• Page Start: 63131
• Page End: 63135
• Publication Date: 2016-07-01
• Subjects: Chemistry -- Periodicals; 540.5
• DOI: 10.1039/c6ra12766e
• Languages: English
• ISSNs: 2046-2069

Abstract

Abstract : A collective formal synthesis approach to six bioactive oxindole alkaloids, including (±)-rhynchophylline and its five homologues, is completed in a highly efficient way. Abstract : A collective formal synthesis approach to bioactive oxindole alkaloids, including (±)-rhynchophylline, (±)-isorhynchophylline, (±)-mitraphylline, (±)-formosanine, (±)-isomitraphylline, and (±)-isoformosanine, is completed in a protecting-group free manner. Besides multigram-scaled operations, the notable feature of the synthesis is the application of two one-pot, sequential transformations. Namely, two key tetracyclic intermediates pyridinium salt9 and monoester14 were prepared by a one-pot N -alkylation/cross-dehydrogenative coupling sequence and a one-pot Michael/Karpocho sequence with minimal purification, respectively.