Enantioselective Total Syntheses of (+)-Ganocin A and (-)-Cochlearol B

Tomoya Mashiko; Yuta Shingai; Jun Sakai; Shinya Adachi; Akinobu Matsuzawa; Shogo Kamo; Kazuyuki Sugita

doi:10.1021/acs.orglett.3c03572

Enantioselective Total Syntheses of (+)-Ganocin A and (-)-Cochlearol B

Org Lett. 2023 Nov 24;25(46):8382-8386. doi: 10.1021/acs.orglett.3c03572. Epub 2023 Nov 13.

Authors

Tomoya Mashiko¹, Yuta Shingai¹, Jun Sakai¹, Shinya Adachi¹, Akinobu Matsuzawa¹, Shogo Kamo¹, Kazuyuki Sugita¹

Affiliation

¹ Department of Synthetic Medicinal Chemistry, Faculty of Pharmaceutical Sciences, Hoshi University, 2-4-41 Ebara, Shinagawa-ku, Tokyo 142-8501, Japan.

PMID: 37955425
DOI: 10.1021/acs.orglett.3c03572

Abstract

Herein, we report the total syntheses of (+)-ganocin A and (-)-cochlearol B, featuring pentacyclic skeletons, in optically active forms. We utilized asymmetric Corey-Bakshi-Shibata reduction, phenolic oxidative cyclization, the intramolecular radical cyclization-benzylic oxidative cyclization sequence, and intramolecular [2 + 2] photocycloaddition. These key steps enabled enantioselective access with the longest linear sequence of 17 steps and 9% overall yield for (+)-ganocin A and with 16 steps and 9% overall yield for (-)-cohlearol B.