Jordanka Petrova

REACTION OF DIMETHYL ESTERS OF 3-METHYL-1,2-ALKADIENEPHOSPHONIC ACIDS WITH METHYLSULFENYL CHLORIDE—ORIENTATION AND STEREOCHEMISTRY

Abstract The reaction of 3-methyl-1,2-alkadienephosphonic acid (i.e.3-alkyl-3-methylsubstituted allenephosphonic) dimethyl esters 1 with methylsulfenyl chloride 2 is oriented mainly to the 1,2-oxaphosphol-3-ene ring products 3a-d (as diastereoisomeric mixtures when alkyl ≠ CH3). In low extent common 1,2-adducts 4a-d as E,Z-mixtures are also formed. The ratio 3:4 and, in particular the E:Z ratio rises by increase of the size of the alkyl group at the allenic C3-atom of 1. Lowering the temperature of the reaction of 1 and 2 leads to an increase of the annulation stereoselectivity although it remains not very high in the studied temperature interval (−45° – +15°C).

CHELATISIERTE ENOLATE VON α-PHOSPHONYLIERTEM ACETALDEHYD

Abstract Es wird gezeigt, daβ mit Lithiumbutyl bei tiefen Temperaturen das Lithiumenolat 6 aus 2 zuganglich ist, wahrend bei Normaltemperatur 2 mit LiBu oder Zinkacetat bevorzugt unter Aldolkondensation zu den Metall-Komplexen des doppelt phosphonylierten Butadienolats oder dem freien E-Enol 8 reagieren. Die Verbindungen werden NMR-spektroskopisch charakterisiert. Einmal gebildetes Li-Enolat 6 ist stabil und zeigt einen selektiven HID-Austausch. It is demonstrated that the lithium enolate 6 is available from 2 with lithiumbutyl at reduced temperature, while the reaction of 2 with Li-butyl or zinc acetate at normal temperature preferably yields the metal-complexes of the doubly phosphonylated butadienolate or the free E-enol 8 via aldolkondensation. The compounds are characterized by nmr-spectroscopy. Once formed Li-enolate 6 is stable and shows a selective H/D-exchange.

5,6-Dihydro-2H-oxaphosphorine-2-oxides by halogenation of 2-chloro-1,3-alkadienylphosphonic dialkyl esters

Abstract Halogenation of 3- and 4-substituted 2-chloro-1,3-alkadienylphosphonic dialkyl esters leads to the formation of six-membered heterocycles derivatives of 5,6-dihydro-2H-1,2-oxaphosphorine-2-oxides. The structure of the products was established by 1H- and 31P-nmr. In one case column chromatography allowed isolation of two diastereomeric six-membered heterocycles without any evidence of formation of non-cyclic or five-membered cyclic products.

Synthesis and Structure of Complexes of the Diethyl Ester of 2-Dimethylamino-2-oxoethylphosphonic Acid with Lanthanide Nitrates

The lanthanide complexes LnL 2 (NO 3 ) 3 ( 3a-g ) are obtained where Ln is La, Sm, Yb, Er, Ce, Eu, Gd, and L is the diethyl ester of 2-dimethylamino-2-oxoethylphosphonic acid [(C 2 H 5 O) 2 P(O)CH 2 CON(CH 3 ) 2 ] 1 . They are characterized by elemental analysis, i.r. and NMR spectroscopy. The crystal structure of 3a is determined by single crystal X-ray diffraction. The complex is found to crystallize in the triclinic space group P 1 with a = 8.4220(17) Å, b = 11.123(2) Å, c = 17.560(4) Å, f = 87.20(3);, g = 82.27(3);, n = 76.89(3);, V = 1587.3(5) Å 3 , Z = 2, calcd = 1.614 mg/m 3 , R = 0.047, R w = 0.107, S = 1.034 for 5762 reflections with I > 2 (I). The structure contains monomeric units of the complex with the lanthanum atom coordinated by 10 oxygen atoms, six of them from the three bidentate nitrate ions and four from the two phosphonate ligands. The coordination is realized by both phosphoryl and amide-carbonyl oxygen atoms. The stereochemistry of the starting ligand 1 is investigated by NMR spectroscopy.

DIETHYL 1-SUBSTITUTED 2-OXO-ETHYLPHOSPHONATES AND THE LITHIUM SALTS AND ZINC COMPLEX OF THEIR ENOL TAUTOMERS

Abstract The lithium salts of diethyl-(1-methyl-2-oxoethyl)phosphonate 1 and diethyl-(2-oxo-1-phenyl-ethyl)phosphonate 2 ( 3 and 4 respectively) as well as the zinc complex of ester 2 ( 5 ) are synthesized and characterized. The lithium salt 3 exists as a mixture of (Z)-and (E)-forms, while the lithium salt 4 and zinc complex 5 have (Z)-chelate structure.

Structures of threo(RR,SS) diethyl ester of 2-hydroxy-1,2-diphenylethylphosphonic acid and (±)diethyl ester of (1-hydroxycyclopentyl)(2-methylphenyl)methylphosphonic acid

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 theυoh stretching frequencies from 3312(1), 3346 (2) cm−1 in solid to 3408(1), 3450(2), in diluted (10−3M) tetrachloromethane solution, indicates the formation of intramolecular hydrogen-bonded species.

REACTION OF LITHIUM DERIVATIVE OF DIETHYL PHENYLMETHANE-PHOSPHONATE WITH KETONES

Abstract The reaction of the lithium derivative of diethyl ester of phenylmethanephosphonic acid (1-Li) with alkanones, cycloalkanones, alkylaryl and diarylketones 2s-b is studied at -70°C in THF. The corresponding adducts-diethyl esters of l-phenyl-2,2-dialkyl(phenyl)-2-hydroxyethanephosphonic acids 3s-h are isolated, their yields being usually higher at short reaction time. The olefination of 3-Li as well as of 3 (both by thermolysis or in acidic media) proceeds in low degree, while in the case of 3-Na the yields of alkenes 4 are good. The relative configurations of 3b. 31 and 3g are determined by IR and NMR-spectra, as well as by their stereospecific olefination. “Threo”-stereoselectivity of the addition stage of the reaction of 1-Li with 2b, 21 and 2g is observed, the “threo”/“erythro” ratio remaining independent on the reaction time.

OLEFIN FORMATION VIA N,N,N′,N′-TETRAMETHYLDIAMIDES OF 1,2-DIARYL-2-HYDROXYETHANEPHOSPHONIC ACIDS IN ACIDIC MEDIA

Abstract The olefin formation via the erythro-N,N,N′N′-tetramethyldiamides of 1,2-diaryl-2-hydroxyethane-phosphonic acids 3, 4 in the presence of aqueous hydrochloric acid proceeds not stereospecifically, while in ethanolic solution of hydrochloric acid (Z)-stereospecific olefin formation predominantly takes place. The mechanism of the elimination process is discussed.

OLEFIN SYNTHESIS VIA THE LITHIUM DERIVATIVES OF THE N,N,N,N′-TETRAMETHYLDIAMIDES OF ARYLMETHANEPHOSPHONIC ACIDS. 2. SYNTHESIS OF SOME (Z)-ORTHO-AND PARA-SUBSTITUTED STILBENES

Abstract The reaction of the lithium derivatives of N,N,N′,N′-tetramethyldiamides of arylmethanephosphonic acids (1-Li) with ortho- and para-substituted benzaldehydes 2 is studied. Reaction conditions are found for erythro-stereoselective addition of 1 to 2 with high diastereomeric purity (95–99%) of the erythro adducts 3, 4 (yields 35–72%). By thermolysis of the adducts in neutral medium the corresponding (Z)-ortho and para-substituted stilbenes 5, 6 are obtained. Some factors causing the predominant formation of the erythro adducts 3, 4, as well as the influence of the ortho-substituents on the equilibrium threo-3, 4 ⇄ erythro-3, 4 are discussed.

REACTION OF THE LITHIUM DERIVATIVE OF DIETHYL 2-(OR 3-)METHYLPHENYLMETHANEPHOSPHONATE WITH KETONES. AN EXAMPLE OF HIGH SYN-STEREOSELECTIVITY

Abstract 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°C in THF, the corresponding adducts—diethyl esters of 1-(2- or 3-methylphenyl)-2,2-dialkyl(phenyl)-2-hydroxy-ethanephosphonic 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.