- Synthesis and reactivity of substituted alkoxymethylphosphonites and their derivatives
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Alkoxy-substituted methylphosphonites and their derivatives are prepared using an organomagnesium method of synthesizing the organophosphorus compounds and alkoxymethylation of various PH acids and their derivatives. Also, certain properties of these promising compounds as important precursors of new functionalized organophosphorue compounds with alkoxymethyl fragments are presented.
- Prishchenko, Andrey A.,Livantsov, Mikhail V.,Novikova, Olga P.,Livantsova, Ludmila I.,Petrosyan, Valery S.
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experimental part
p. 281 - 289
(2012/07/28)
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- Molecular basis of chiral acid recognition by Candida rugosa lipase: X-ray structure of transition state analog and modeling of the hydrolysis of methyl 2-methoxy-2-phenylacetate
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Lipase from Candida rugosa shows high enantioselectivity toward α-substituted chiral acids such as 2-arylpropionic acids. To understand how Candida rugosa lipase (CRL) distinguishes between enantiomers of chiral acids, we determined the X-ray crystal stru
- Colton, Ian J.,Yin,Grochulski, Pawel,Kazlauskas, Romas J.
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experimental part
p. 2529 - 2544
(2011/11/29)
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- Enantioselective copper-catalyzed O-H insertion of α-diazo phosphonates
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A copper-catalyzed asymmetric O-H insertion of -di-azo phosphonates with alcohols by using chiral spiro bisoxazoline ligands was developed. The insertion reaction exhibited good yields (up to 89%) with high enantioselectivities (up to 98% ee) and provided
- Zhu, Shou-Fei,Chen, Wang-Qiao,Zhang, Qian-Qian,Mao, Hong-Xiang,Zhou, Qi-Lin
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scheme or table
p. 919 - 922
(2011/06/17)
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- Use of the Wadsworth-Emmons reaction for preparing hindered vinyl ethers and related 1,2-dioxetanes
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Arylaldehyde acctals can be reacted with trimethyl phosphite to produce the corresponding dimethyl α-methoxy-benzylphosphonates, themselves used in a Wadsworth-Emmons reaction with adamantanone to produce hindered methyl vinyl ethers. These vinyl ethers are useful in the preparation of chemiluminescent 1,2-dioxetanes. The scope of the reaction has been explored.
- Roeschlaub, Carl A.,Sammes, Peter G.
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p. 2243 - 2248
(2007/10/03)
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- CHEMICAL SHIFT NON-EQUIVALENCE IN THE NMR SPECTROSCOPY OF DIALKYL α-HYDROXYBENZYL- AND DIALKYL α-METHOXYBENZYLPHOSPHONATES AND THE CRYSTAL STRUCTURE OF DIMETHYL α-CHLOROMETHYL-α-HYDROXYBENZYLPHOSPHONATE
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Single crystal X-ray diffraction of dimethyl α-chloromethyl-α-hydroxybenzylphosphonate shows the compound to exist as hydrogen-bonded dimers in the solid state.In solution, 1H and 13C nmr spectroscopy reveal chemical shift non-equivalence of the corresponding nuclei in the two alkoxy groups of dialkyl α-hydroxybenzyl- and dialkyl α-methoxybenzylphosphonates, an effect that is attributed primarily to the presence of the chiral α-carbon atom, although restriction of rotation about the P-Cα bond by intermolecular hydrogen-bonding may also be a factor in the α-hydroxy compounds.Chemical shift non-equivalence of the α-halogenomethyl protons in dimethyl α-halogenomethyl-α-hydroxybenzylphosphonates is significantly greater for the chloro- than for the bromo-compound.Keywords: X-ray crystal structure; nmr spectroscopy; chemical shift non-equivalence; α-hydroxyphosphonates; α-methoxyphosphonates.
- Hudson, Harry R.,McPartlin, Mary,Matthews, Ray W.,Powell, Harold R.,Yusuf, Ramon O.,et al.
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p. 239 - 244
(2007/10/02)
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- PHOTOLYSIS OF DIPHOSPHONATE DERIVATIVES HAVING AROMATIC RING ASSEMBLIES
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Upon UV-irradiation in methanol the diphosphonates fully substituted with aromatic rings give biaryls and aryl(dimethoxy)carbene derivatives in quantum yield of 0.01-0.03.The mechanism of the selective α,α-elimination of aryl groups was discussed.
- Shi, Min,Okamoto, Yoshiki,Takamuku, Setsuo
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p. 101 - 107
(2007/10/02)
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- Photolysis of triarylmethylphosphonic acids and their esters
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Upon UV-irradiation in an alkaline alcohol solution, some triarylmethylphosphonic acids underwent C-P bond cleavage to give triarylmethanes and alkyl dihydrogenphosphates, while, in an acidic or a neutral alcohol solution, they afforded biaryls. Their dimethyl esters gave also biaryls and dimethyl [alkoxy(aryl)methyl]phosphonates, which were derived from the insertion of (dialkoxyphosphinyl) arylcarbenes into the OH bond of the alcohol. The carbene was generated by photo-α,α-elimination of two aryl groups of the phosphonate.
- Shi,Okamoto,Takamuku
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p. 453 - 460
(2007/10/02)
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- Neighbouring Phosphonate Group Participation in Carbene Chemistry
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Systematic studies of the effect of the neighbouring phosphonate group on the reactivities of carbene showed that the neighbouring phosphonate group exerts prominent effects on both the product distribution and the reaction products; the results are interpreted as indicating the extent of participation, which seems to be sensitive to the carbenic substituents.
- Tomioka, Hideo,Hirai, Katsuyuki
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p. 1611 - 1613
(2007/10/02)
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- Effect of the Phosphonate Group on the Reactivity of Carbenes. Neighbouring Phosphonate Group Participation
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The electrophilicity of phosphonylcarbenes is dramatically reduced as one changes the neighbouring group from the phosphonate ester to the acid anion, and phosphonate carbenes are experimentally classified as typical nucleophiles; the results are nicely explained in terms of neighbouring phosphonate group perticipation in which the vacant p orbital strongly interacts with the phosphonate oxygen anion resulting in suppression of the availability of the vacant p orbital.
- Tomioka, Hideo,Hirai, Katsuyuki
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p. 362 - 364
(2007/10/02)
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