Huang YQ, Huang XZ, Huang PQ. Synthesis of 5-(1-Alkoxyalkylidene)tetronates by Direct Condensation Reactions of Tetronates with Thionolactones and Thionoesters.
J Org Chem 2021;
86:2359-2368. [PMID:
33491453 DOI:
10.1021/acs.joc.0c02502]
[Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We report a two-step approach to bicyclic and monocyclic 5-(1-alkoxyalkylidene)tetronates starting from lactones/esters. The method features the use of thionolactones and thionoesters as activated forms of lactones/esters that allows the direct condensation with tetronates via one-pot enolate formation, nucleophilic addition, S-methylation, and DBU-promoted elimination. The value of the method was demonstrated by the stereoselective syntheses of two natural products: 5,6-Z-fadyenolide (Z/E ratio = 6:1) and 9,10-methylenedioxy-5,6-Z-fadyenolide (Z/E ratio = 9:1).
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