Studies on the reaction of trityl derivatives with H‐phosphonate diesters: Their relevance to the synthesis of 4‐pyridylphosphonates

Transesterification of diphenyl H‐phosphonate with tritanol in pyridine afforded equimolar amounts of phenyl H‐phosphonate monoester and diphenyl 4‐pyridylphosphonate as the only phosphorus‐containing species. Using ³¹P NMR spectroscopy a plausible reaction pathway for the observed transformation was proposed and some of the postulated intermediates were identified. These studies also enabled us to develop an efficient protocol for the formation of diphenyl and diethyl 4‐pyridylphosphonates from the corresponding H‐phosphonate diesters under mild reaction conditions. © 1999 John Wiley & Sons, Inc. Heteroatom Chem 10: 492–499, 1999