Expedient Construction of the [5‐6‐7] Tricyclic Core of Calyciphylline A‐Type Alkaloids. Issue 4 (5th November 2014)

• Record Type: Journal Article
• Authors: Guo, Jing‐Jing; Li, Yun; Cheng, Bin; Xu, Tingting; Tao, Cheng; Yang, Xinkan; Zhang, Denghong; Yan, Guangqi; Zhai, Hongbin
• Is Part Of: Chemistry, an Asian journal. Volume 10:Issue 4(2015:Apr.)
• Page Start: 865
• Page End: 868
• Publication Date: 2014-11-05
• Subjects: calyciphylline A‐type -- daphniphyllum alkaloids -- Diels–Alder -- natural products -- ring expansion; Chemistry -- Periodicals; 540.5
• DOI: 10.1002/asia.201403061
• Languages: English
• ISSNs: 1861-4728

Abstract

Abstract: An efficient synthetic route toward the highly congested [5‐6‐7] tricyclic core of calyciphylline A‐type alkaloids has been developed. This approach features a highly efficient intramolecular Diels–Alder cycloaddition to establish the aza‐five‐membered C ring as well as the C1 all‐carbon quaternary center, and a subsequent cyclopropanation together with a ring‐expansion reaction of the resulted adduct to construct the seven‐membered D ring. Abstract : Ring a Ding Ding ! An efficient route to establish the highly congested [5‐6‐7] tricyclic core commonly present in daphlongamine E and other members of calyciphylline A‐type alkaloids has been developed, based on an intramolecular Diels–Alder cycloaddition to forge the aza‐five‐membered C ring, the C1 all‐carbon quaternary center as well as the precursor of [6/3] fused‐ring system in a single operation, and a subsequent ring‐expansion reaction to form the seven‐membered D ring.