Imidazolium ylide mediated tandem Knoevenagel–Michael–O-cyclization sequence for the synthesis of multi-substituted 4,5-dihydrofurans

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• Crystallographic data for compounds 4b and 4l in this article have been deposited with the Cambridge Crystallographic Data Centre as supplementary publication numbers 1,023,393 and 1,023,391, respectively. Copies of the data can be obtained, free of charge, on application to CCDC, 12 Union Road, Cambridge CB2 1EZ, UK (fax: +44 (0) 1223 336033 or e-mail:[email protected]).
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