Breunig M, Yuan P, Gaich T. An Unexpected Transannular [4+2] Cycloaddition during the Total Synthesis of (+)-Norcembrene 5.
Angew Chem Int Ed Engl 2020;
59:5521-5525. [PMID:
31750980 PMCID:
PMC7155007 DOI:
10.1002/anie.201912613]
[Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2019] [Revised: 11/04/2019] [Indexed: 11/26/2022]
Abstract
We report a concise and versatile total synthesis of the diterpenoid (+)-norcembrene 5 from simple building blocks. Ring-closing metathesis and an auxiliary-directed 1,4-addition are the key steps of our synthetic route. During the synthesis, an unprecedented, highly oxidized pentacyclic structural motif was established from a furanocembranoid through transannular [4+2] cycloaddition.
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