(S(s)-5-ethoxy-3-p-tolylsulfinylfuran-2(5H)-ones as chiral dipolarophiles: First asymmetric cycloaddition of diazomethane to vinyl sulfoxides

Article abstract of DOI:10.1016/0957-4166(96)00233-9

Cycloadditions of diazomethane to (S(s)-5-ethoxy-3-p-tolylsulfinylfuran-(2(5H)-ones 1a-b and their corresponding 4-methyl derivatives 3a-b, proceeds in quantitative yields, to give enantiomerically pure 3H,6H,3a-6a-dihydrofuro[3,4-c]pyrazol-4-ones 2a-b an