Сharacterization and stereochemistry of alkyl 2-chloro- 3-formylacrylates: experimental NMR and theoretical DFT studies
T.M. Barhoumi-slimi, M.T. Ben dhia, M. Nsangou, M.M. El gaied, M.R. Khaddar
Keywords: synthesis, Vilsmeier reaction, stereoisomerism, stereoselectivity, cyclization, NMR, NOEDIFF, B3LYP
Pages: 266-271
Abstract
The synthesis of alkyl 2-chloro-3-formylacrylates 1 from alkyl pyruvates was carried out using Vilsmeier reaction. The reaction is highly stereoselective and leads to a 95:5 mixture of Z and E stereoisomers. Both stereoisomers were characterized by 1H and 13C NMR. In CDCl3 solution, the NMR data, particularly the NOEDIFF experiments, show that the major species formed is the Z stereoisomer. Heating compound 1 in THF at reflux afforded the cyclic product 2 in 90 % yield. The interpretation of the experimental data were further supported by DFT/B3LYP calculations.
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