Synthesis of dimethyl-1-(trifluoromethyl)-3H-pyrrolizine-2,3-dicarboxylate using phosphorus compounds

Abstract

A general and practical route for the synthesis of phosphorus compounds containing trifluoromethyl or trichloromethyl groups by a one-pot condensation triphenylphosphine and dialkyl acetylenedicarboxylate in the presence of an NH-acid such as 2,2,2-trifluoro-1-(1Hpyrrol-2-yl)ethanone or 2,2,2-trichloro-1-(1H-pyrrol-2-yl)ethanone is described. The product obtained from the fluorinated compound undergoes an intramolecular Wittig reaction in boiling THF. This method offers a simple procedure for the preparation of dimethyl 1-(trifluoromethyl)-3H-pyrrolizine-2, 3-dicarboxylate.