142474-99-5Relevant academic research and scientific papers
Structures of threo(RR,SS) diethyl ester of 2-hydroxy-1,2-diphenylethylphosphonic acid (+/-)diethyl ester of (1-hydroxycyclopentyl)(2-methylphenyl)methylphosphonic acid
Angelova, O.,Macicek, J.,Vassilev, N. G.,Momchilova, S.,Petrova, J.
, p. 253 - 258 (1992)
The crystal structures of threo(RR,SS) diethyl ester of 2-hydroxy-1,2-diphenylethylphosphonic acid (1) and of (+/-)diethyl ester of (1-hydroxycyclopentyl)(2-methylphenyl)methylphosphonic acid (2) have been solved by X-ray methods.They are built up in a similar way to centrosymmetric dimers of hydrogen-bonded molecules.The orientation of the substituents around the central C-C bond in both molecules fulfills the requirement for the least spatial hindrance.The observed shift of the vOH stretching frequencies from 3312(1), 3346(2) cm-1 in solid to 3408(1), 3450(2), in diluted (10-3 M) tetrachloromethane solution, indicates the formation of intramolecular hydrogenbonded species.
REACTION OF THE LITHIUM DERIVATIVE OF DIETHYL 2-(OR 3-)METHYLPHENYLMETHANEPHOSPHONATE WITH KETONES. AN EXAMPLE OF HIGH SYN-STEREOSELECTIVITY
Vassilev, Nikolay G.,Petrova, Jordanka,Kirilov, Marko
, p. 49 - 58 (2007/10/02)
The reaction of the lithium derivative of diethyl ester of 2-(or 3-)methylphenylmethanephosphonic acid (1-Li) with a large number of symmetric and unsymmetric ketones 2a-r is studied at -70 deg C in THF, the corresponding adducts-diethyl esters of 1-(2- or 3-methylphenyl)-2,2-dialkyl(phenyl)-2-hydroxyethanephosphonic acid 3a-r being isolated.The results of stereospecific olefination of the β-hydroxyphosphonates 3j, 3k, 3o and 3p indicate the influence of combined steric effects in ketones 2 and ortho- and metha-methyl substituted benzylphosphonates 1.Spectral investigations and PM3-calculations prove high synstereoselectivity of the reaction of ortho-methyl substituted benzylphosphonates 1a with studied ketones. Key words: Stereoselectivity; arylmethanephosphonate carbanion; reaction with ketones; 2-hydroxyethanephosphonates; atropisomers; PM3-calculations.
