Non-stabilized azomethine ylides in [3 + 2] cycloadditions. Pyrrolidinylfuranones from (5S
)-5-menthyloxy-4-vinylfuran-2(5H
)-one
Abstract
Upon sonication with lithium fluoride in acetonitrile N-benzyl-N-methoxymethyl(trimethylsilylmethyl)amines 9a–c undergo chemoselective 1,3-dipolar cycloaddition with 4-vinylfuranones 2 and 6 to afford pyrrolidinylfuranones 10, 11a–c and 12a–c. The stereochemistry is assigned by X-ray analyses and proton NMR data comparison of related oxiranylfuranone 13.