Synlett 2018; 29(15): 1978-1982
DOI: 10.1055/s-0037-1610258
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© Georg Thieme Verlag Stuttgart · New York

Synthesis of Polycyclic Frameworks through Iron-Catalyzed Intramolecular [5+2] Cycloaddition

Yongjiang Liu
Key Laboratory of Green Chemistry &Technology of Ministry of Education, College of Chemistry, Sichuan University, Chengdu 610064, P. R. of China   Email: chembliu@scu.edu.cn   Email: fsm09@aliyun.com
,
Yanhui Zhang
Key Laboratory of Green Chemistry &Technology of Ministry of Education, College of Chemistry, Sichuan University, Chengdu 610064, P. R. of China   Email: chembliu@scu.edu.cn   Email: fsm09@aliyun.com
,
Xiao Wang
Key Laboratory of Green Chemistry &Technology of Ministry of Education, College of Chemistry, Sichuan University, Chengdu 610064, P. R. of China   Email: chembliu@scu.edu.cn   Email: fsm09@aliyun.com
,
Shaomin Fu*
Key Laboratory of Green Chemistry &Technology of Ministry of Education, College of Chemistry, Sichuan University, Chengdu 610064, P. R. of China   Email: chembliu@scu.edu.cn   Email: fsm09@aliyun.com
,
Bo Liu  *
Key Laboratory of Green Chemistry &Technology of Ministry of Education, College of Chemistry, Sichuan University, Chengdu 610064, P. R. of China   Email: chembliu@scu.edu.cn   Email: fsm09@aliyun.com
› Author Affiliations

We acknowledge financial support from the NSFC (21672153).
Further Information

Publication History

Received: 08 July 2018

Accepted after revision: 26 July 2018

Publication Date:
23 August 2018 (online)


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Abstract

A concise and efficient approach to the core of the C18/C19 diterpenoid alkaloids and phomopsterone B is reported. Both syntheses share the same iron-catalyzed intramolecular [5+2] cycloaddition to assemble the tricyclo[6.3.1.01,6]]dodecane skeleton. The following ­approach to the 6/5/6/7 tetracyclic core scaffold of C18/C19 diterpenoid alkaloids features a regioselective Grignard addition/thermal Claisen rearrangement/RCM cyclization. Meanwhile the synthetic steps to access the spiro 6/5/6 tricyclic subunits of phomopsterone B were characterized as intramolecular aldol reaction, Wacker oxidation, and Criegee ­reaction.

Supporting Information