SYNTHESIS OF FUNCTIONAL FURAN-DERIVATIVES VIA ENOXYSILANE INTERMEDIATES - CROSSED ALDOLIZATION AND MICHAEL ADDITION CATALYZED BY BICL3-METAL IODIDE SYSTEMS

The catalytic Mukaiyama-aldol reaction using bismuth (III) chloride-so dium or zinc iodide as catalytic systems has been applied to the furan series to obtain furyl beta-ketols or beta-hydroxyesters in high yiel ds. These new catalysts operate under mild conditions, preventing seco ndary reactions (resinification, crotonisation) and allowing the isola tion of intermediate silylated derivatives. Simple diastereoselectivit y was observed for aldol condensations involving furan-2-carbaldehyde. Furyl 1,5-diketones and delta-oxoesters were also prepared using the Michael addition with the same catalysts.