87198-52-5Relevant academic research and scientific papers
Mechanism of the Reaction of Trialkyl Phosphites with α-Halogenoacetophenones in Alcoholic Solvents
Petnehazy, Imre,Keglevich, Gyoergy,Toeke, Laszlo,Hudson, Harry R.
, p. 127 - 132 (2007/10/02)
Second-order rate constants and activation parameters have been determined for the reactions of trialkyl phosphites in alcoholic media with α-chloro- or α-bromo-acetophenones having various substituents in the benzene ring (3,4-Me2, 4-Me, H, 4-Cl, and 4-I).Linear Hammett plots are consistent with the involvement of a common first intermediate in the rate-determining stage, leading to the formation of vinyl phosphate, α-hydroxyphosphonate, and acetophenone.The results provide the first kinetic evidence in support of the initial formation of the previously suggested betaine as a common intermediate in alcoholic solution.Further reaction then involves rearrangement to give the vinyloxyphosphonium species (and hence the Perkow product) or protonation followed by dealkylation to give the α-hydroxyphosphonate.Evidence for the possible formation of dehalogenated ketone via solvolysis of the α-hydroxyphosphonium intermediate is also presented.
FACTORS IN THE CONTROL OF PRODUCT COMPOSITION IN THE REACTIONS OF TRIALKYL PHOSPHITES WITH α-HALOGENOACETOPHENONES IN ALCOHOLIC MEDIA
Keglevich, Gyoergy,Petnehazy, Imre,Toeke, Laszlo
, p. 341 - 350 (2007/10/02)
α-Hydroxyphosphonates are formed, in addition to vinyl phosphates and dehalogenated ketones, in the reactions of trimethyl phosphite (in methanol) or triethyl phosphite (in ethanol) with variously substituted α-chloro, α-bromo, and α,α-dichloro-acetophenones.Tri-isopropyl phosphite in propan-2-ol gives only the vinyl phosphate.Ketophosphonates are not detectable amongst the reaction products under the conditions used.Trends in product composition can be correlated with the leaving ability of halogen, substituent effects, structure of the phosphite, and reaction temperature.Additional products are obtained in the reactions of trimethyl phosphite in methanol with 4-nitro-α-chloroacetophenone, which gives the dehalogenated hydroxyphosphonate, and with the α,α-dichloroacetophenones which undergo monodehalogenation.Twenty three new α-hydroxyphosphonates are reported.
