α-Hydroxyphosphonates as intermediates in the Kabachnik–Fields reaction: New proof of their reversible formation

The rearrangement of dimethyl α-hydroxybenzylphosphonate to the corresponding benzylphosphate in the presence of an alkali carbonate in acetone under phase transfer catalytic conditions was accompanied by the formation of dimethyl α–hydroxyisopropylphosphonate, proving the reversibility of the formation of the hydroxyphosphonate from benzaldehyde and dimethyl phosphite in the Pudovik reaction. The dimethyl phosphite formed in situ from the adduct under the conditions of the rearrangement reaction was trapped by acetone.