Confirmation of the stereochemistry of spiroviolene

Yao Kong; Yuanning Liu; Kaibiao Wang; Tao Wang; Chen Wang; Ben Ai; Hongli Jia; Guohui Pan; Min Yin; Zhengren Xu

doi:10.3762/bjoc.20.77

Confirmation of the stereochemistry of spiroviolene

Beilstein J Org Chem. 2024 Apr 18:20:852-858. doi: 10.3762/bjoc.20.77. eCollection 2024.

Authors

Yao Kong^#¹, Yuanning Liu^#¹, Kaibiao Wang¹, Tao Wang¹, Chen Wang¹, Ben Ai¹, Hongli Jia¹, Guohui Pan², Min Yin³, Zhengren Xu¹

Affiliations

¹ State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, Beijing 100191, China; Ningbo Institute of Marine Medicine, Peking University, Ningbo 315010, China.
² State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China.
³ School of Medicine, Yunnan University, 2 North Cui Hu Road, Kunming 650091, China.

^# Contributed equally.

Abstract

We confirm the previously revised stereochemistry of spiroviolene by X-ray crystallographically characterizing a hydrazone derivative of 9-oxospiroviolane, which is synthesized by hydroboration/oxidation of spiroviolene followed by oxidation of the resultant hydroxy group. An unexpected thermal boron migration occurred during the hydroboration process of spiroviolene that resulted in the production of a mixture of 1α-hydroxyspiroviolane, 9α- and 9β-hydroxyspiroviolane after oxidation. The assertion of the cis-orientation of the 19- and 20-methyl groups provided further support for the revised cyclization mechanism of spiroviolene.

Keywords: boron migration; diterpene; spiroviolene; stereochemistry.

Grants and funding

We are grateful to the National Natural Science Foundation of China (No. 81973197, 81991525, 22107008), Beijing Natural Science Foundation (No. Z210007), and Peking University Medicine Fund for world’s leading discipline (BMU2022DJXK002) for financial support.