Lima S, Coelho F. Synthesis of 1,4,6-Tricarbonyl Compounds via Regioselective Gold(I)-Catalyzed Alkyne Hydration and Their Application in the Synthesis of α-Arylidene-butyrolactones.
ACS OMEGA 2020;
5:8032-8045. [PMID:
32309713 PMCID:
PMC7161055 DOI:
10.1021/acsomega.0c00101]
[Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Accepted: 03/20/2020] [Indexed: 05/05/2023]
Abstract
We report a direct, straightforward, and regioselective hydration of 1,4-enynes designed from Morita-Baylis-Hillman adducts. Under smooth conditions and short reaction times, gold-catalyzed hydration of internal alkynes provides synthetically useful ketones as single regioisomers in yields higher than 90%. The synthetic usefulness of this protocol was demonstrated by the conversion of selected ketones into biologically valuable α-alkylidene-γ-lactones upon reduction with sodium borohydride. In the course of the scope evaluation, we discovered that this methodology could also furnish α-arylidene-β,γ-butenolides.
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