Ng K, Minehan TG. A Single-Flask Synthesis of Morita-Baylis-Hillman Adducts from Ethoxyacetylene and Carbonyl Compounds: Synthesis of Subamolides D and E.
Org Lett 2016;
18:4028-31. [PMID:
27490948 DOI:
10.1021/acs.orglett.6b01772]
[Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Sequential treatment of (ethoxyethynyl)lithium with aldehydes and/or ketones (2 and 4) and BF3·OEt2 gives rise to β-hydroxyenoates 5 in good to excellent overall yields. Similarly, the combination of 1 (M = Li) and dicarbonyl compounds 6 (X = O) or keto/aldehyde acetals (X = OMe) followed by the addition of a Lewis acid leads to five-, six-, and seven-membered hydroxycycloalkene carboxyates. The utility of this method is demonstrated in the synthesis of the α-alkylidene lactone natural products subamolide D and E.
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