Synthesis of the [6-6-7-5-5] Pentacyclic Core of Calyciphylline N

Zhiwen Zhao; Guowei Deng; Chuang-Chuang Li

doi:10.1021/acs.orglett.4c00437

Synthesis of the [6-6-7-5-5] Pentacyclic Core of Calyciphylline N

Org Lett. 2024 Mar 22;26(11):2238-2242. doi: 10.1021/acs.orglett.4c00437. Epub 2024 Mar 4.

Authors

Zhiwen Zhao¹, Guowei Deng¹, Chuang-Chuang Li^{1

2}

Affiliations

¹ Shenzhen Grubbs Institute, Department of Chemistry, Guangming Advanced Research Institute, Southern University of Science and Technology, Shenzhen, Guangdong 518055, People's Republic of China.
² Shenzhen Bay Laboratory, Shenzhen, Guangdong 518132, People's Republic of China.

PMID: 38442391
DOI: 10.1021/acs.orglett.4c00437

Abstract

A new approach for the concise 11-step synthesis of the [6-6-7-5-5] BCDEF pentacyclic core of calyciphylline N is described. A type II [5 + 2] cycloaddition was employed to construct the strained BCD skeleton, which encompasses the challenging bicyclo[2.2.2] and bicyclo[4.3.1] ring systems. With a regio- and diastereoselective Lu's [3 + 2] cycloaddition, followed by intramolecular aldol cyclization and elimination, the desired [5-5]-fused EF ring system has been successfully installed, resulting in the complete carbocyclic skeleton of calyciphylline N.