Studies on the Synthesis of Furan Derivatives. XLVI. : The Olefination of Carbamoylmethylenetriphenylphosphoranes with 5-Nitro-2-furfural

Abstract

Olefination of 14 kinds of furan system carbamoylmethylenetriphenylphosphoranes (Ia to IVb) and 5-nitro-2-furfural (VI) was attempted but objective compounds were not obtained from any of them. Reaction of four kinds of phenylcarbamoylmethylenetri-phenylphosphoranes (Va to Vd) with VI gave the objective amido olefin compound (VIIIa) alone from Va, VIIIb and a by-product olefin compound (IXb) from Vb, IXc, VIIIc, and the betaine compound (VIIc) of the latter from Vc, and only IXd from Vd. Formation mechanism of the olefins (IXb to IXd) was assumed to involve thermal dissociation of Vb to Vd.