Sequential nitromethane conjugate addition/elimination - Pd-catalyzed allylation of β-trifloxy acrylates. Application to carbapenem synthesis

(formula presented) Sequential reactions of nitromethane via conjugate addition - elimination to B-trifloxy acrylates followed by Pd-catalyzed substitution of the resulting allyl nitro compounds with nucleophiles afforded homologation products at the β-position. 2-Naphthosultammethyl carbapenem, pan anti-MRS carbapenem intermediate, was prepared in one pot from the corresponding 2-trifloxy compound. The scope and limitation of the one-pot method were investigated using several cyclic unsaturated esters and nucleophiles.