Arbuzov reactions of diethyl2,2,2-trihaloethyl phosphites (3) with benzoyl chloride afforded ethyl 2,2,2-trihaloethyl benzoylphosphonates (4). The reactions of 4 with NH,OH.HCl led to the formation of methyl benzoate and ethyl methyl H-phosphonate as a result of alcoholysis of 4, followed by alkoxy group exchange. Methanol solutions of benzoylphosphonates 4 were found by 31P NMR spectroscopy to contain considerable proportions of hemiacetals, 7, which undergo base-catalyzed C-P bond cleavage. The formation of heniiacetals from benzoyZphosphonates 4 is suppressed in 2-propanol, and i n this solvent the corresponding oxinzes 2 could be obtained in good yields. Reactions of methyl benzoylphosphonochloridate (1 0 ) with 2,2,2-trihaloethanolss, in CH2C12 gave methyl 2,2,2-trihaloethyl benzoylphosphonates (1 1) which could be converted directly 10 oxinzes 12 by NH20H.HCl in a one-pot procedure. In contrast to the previously studied dimethyl (E)-a-hydroxyiniinobenzylphosphonate, which underwent thermal Beckmann rearrangement to afford N-benzoylphosphorarnidates, both (E) and (Z)-trihabethyl esters 2 and 12 underwent fragmentation to benzonitrile and to the corresponding dialkyl hydrogen phosphate, reflecting the increased electrophilicity of the phosphorus in these compounds. Deniethylation of methyl esters 12 was effected smoothly by iodide or bromide ions to yield benzoylphosphonate salts 15, which i n turn were con-*To whom correspondence should be addressed. This paper is dedicated to Professor Herbert C. Brown on the occasion of his 80th birthday.