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DOI: 10.1055/s-0036-1588078
One-Pot Synthesis of α-Ylidene δ-Lactones from Functionalized Allylic Bromides in a Water–Isopropanol Medium
Publication History
Received: 26 July 2016
Accepted after revision: 06 September 2016
Publication Date:
13 October 2016 (online)


Abstract
The one-pot microwave-assisted synthesis of a series of α-ylidene δ-lactones from (Z)-2-(bromomethyl)-2-alkenoates (derived from Morita–Baylis–Hillman reaction) in an aqueous environment is reported. The protocol includes regioselective base-mediated allylation of ethyl acetoacetate with (Z)-2-(bromomethyl)-2-alkenoates followed by decarboxylative hydrolysis, carbonyl reduction of the keto carboxylate intermediate, and acid-mediated cyclization of the resulting δ-hydroxy acid to furnish the α-ylidene δ-lactones with good overall yields. The synthesis was also performed in the stepwise mode, which allowed the isolation and full characterization of each intermediate involved in the one-pot method. The main features of this efficient transformation include the fast reaction rates, the use of a benign aqueous medium, the use of inexpensive and readily available reagents, the production of nearly innocuous residues, and the requirement for a single work-up and purification stage at the end of the process.
Key words
allylic bromide - δ-lactone - green chemistry - microwave - one-pot - Morita–Baylis–HillmanSupporting Information
- Supporting information for this article is available online at http://dx.doi.org/10.1055/s-0036-1588078.
- Supporting Information