Synthesis and intramolecular cyclization of diethylphosphono-substituted allenic glycols

This paper describes a convenient and efficient synthesis of new (2R)-5-substituted-5-(diethylphosphono)-penta-3,4-dien-1,2-diols. Phosphorylated allenic glycols are stable enough compounds, but under basic conditions they cyclized to (3R)-5-(3-hydroxy-2,3-dihydrofuryl) (diethylphosphono) alkanes through intramolecular nucleophilic addition of the terminal alkoxide to the central carbon atom of the allene system. Treatment of (3R)-5-(3-hydroxy-2,3-dihydrofuryl)(diethylphosphono)alkanes with a catalytic amount of p-toluenesulfonic acid in chloroform at 40-45 degreesC for 0.5 hours afforded diethylphosphono(2-furyl)alkanes.