Département de chimie moléculaire

Novel C-ethoxycarbonyl cyclic ketonitrones are synthesized from the Ag- or Cu-catalyzed ring expansion of $\beta$-diazo cyclic hydroxylamines. The latter are themselves easily obtained by the addn. of lithiated Et diazoacetate onto cyclic nitrones. The regioselective metal-catalyzed rearrangement of $\beta$-diazo cyclic hydroxylamines proved highly efficient and resulted in a synthetically useful ring expansion to produce 6- or 7-membered ring functionalized nitrones. The outcome of the two steps, i.e. nucleophilic addn. of $\alpha$-diazoesters to nitrones and ring expansion, is a formal nitrone homologation. [on SciFinder(R)]