Yb(OTf)3-catalyzed Vinylogous Mannich Reaction of Trialkylsilyloxyfuran

Abstract

The one-pot three-component vinylogous Mannich reaction of trialkylsilyloxyfurans with anilines and aldehydes in the presence of catalytic amounts of Yb(OTf) 3 gave the substituted aminoalkyl-butenolides in good yields (>90 %) and diastereoselectivities (d.e. > 60 %). The configuration of the major product is erythro (anti) and was confirmed by chemical transformation into piperidinone derivatives and 1 H NMR spectral studies of the latter compounds. The vinylogous Mannich reaction performed with preformed imines proceeded similarly with a preferred erythro selectivity while the condensation of 3-methyl-2-trialkylsilyloxyfurans was threo selective.