American Chemical Society
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A Single-Flask Synthesis of Morita–Baylis–Hillman Adducts from Ethoxyacetylene and Carbonyl Compounds: Synthesis of Subamolides D and E

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journal contribution
posted on 2016-08-04, 00:00 authored by Kevin Ng, Thomas G. Minehan
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.