Zhang C, Li J, Wang X, Shen X, Zhu D, Shen R. Metal-Free Synthetic Shortcut to Octahydro-Dipyrroloquinoline Skeletons from 2,5-Cyclohexadienone Derivatives and l-Proline.
J Org Chem 2021;
86:10397-10406. [PMID:
34283586 DOI:
10.1021/acs.joc.1c01083]
[Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The tandem decarboxylative condensation-dimerization reaction of l-proline with 2,5-cyclohexadienones including p-quinone monoacetals, p-quinol ethers, and p-quinols is reported to provide a concise and rapid synthesis of octahydro-dipyrroloquinoline compounds. The reaction features the use of cost-effective and readily available starting materials, high efficiency, metal-free and green reaction conditions. The reaction is applied to the synthesis of incargranine B aglycone. The discovery of this reaction may suggest a biosynthetic pathway from 2,5-cyclohexadienones and proline for natural ingredients containing pyrroloquinoline moieties.
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