Total Syntheses of Phleghenrines A and C

• Authors: Xinpei Cai, Purdue University; Lei Li, Purdue University; Ye-Cheng Wang, Purdue University; Jianhan Zhou, Purdue University; Mingji Dai, Emory University
• Journal Title: ORGANIC LETTERS
• Volume: Volume 25, Number 28
• Publisher: American Chemical Society | 2023-07-11, Pages 5258-5261
• Type of Work: Article | Final Publisher PDF
• Publisher DOI: http://doi.org/10.1021/acs.orglett.3c01784
• Subjects: Chemistry, Organic; Health Sciences, Oncology
• Keywords: Science & Technology; Physical Sciences; Chemistry, Organic; Chemistry; MASKED O-BENZOQUINONES; LYCOPODIUM ALKALOIDS; EFFICIENT SYNTHESIS; LYCONADINS; HUPERZINE

Abstract

Herein, we report the total syntheses of phleghenrines A and C from commercially available starting materials in 7 and 8 steps, respectively. Notable steps include an inverse electron-demand Diels-Alder reaction between a masked o-benzoquinone and a N-protected enamine to prepare one key intermediate with a bicyclo[2.2.2]octenone core, a Büchner-Curtius-Schlotterbeck one-carbon insertion to expand the bicyclo[2.2.2]octenone to a bicyclo[3.2.2]nonenone, and Trauner’s modified 2-pyridone synthesis to install the 2-pyridone moiety.