Kaplan HZ, Rendina VL, Kingsbury JS. General Methodologies Toward cis-Fused Quinone Sesquiterpenoids. Enantiospecific Synthesis of the epi-Ilimaquinone Core Featuring Sc-Catalyzed Ring Expansion.
Molecules 2017;
22:molecules22071041. [PMID:
28672821 PMCID:
PMC6152358 DOI:
10.3390/molecules22071041]
[Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Revised: 06/21/2017] [Accepted: 06/21/2017] [Indexed: 11/28/2022] Open
Abstract
A stereocontrolled approach to the cis-decalin framework of clerodane diterpenes and biologically active quinone sesquiterpenes is reported. Starting from an inexpensive optically pure tetrahydroindanone, Birch reductive alkylation builds two new contiguous chiral centers—one of which is quaternary and all-carbon-substituted. Also featured is a highly regioselective diazoalkane—carbonyl homologation reaction to prepare the 6,6-bicyclic skeleton. Therein, the utility of Sc(OTf)3 as a mild catalyst for formal 1C insertion in complex settings is demonstrated.
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