Search

A reaction of 2,2,2-trihalobenzo-1,3,2-dioxaphospholes with terminal alkylacetylenes proceeds under mild conditions (∼20 °C) and leads to the formation of 4-alkylbenzo[ e]-1,2-oxaphosphinine 2-oxide derivatives. The presence of aliphatic substituents in acetylene decreases (as compared to their aromatic counterparts described earlier) regioselectivity of halogenation of benzo fragment in 4-alkylbenzo[ e]-1,2-oxaphosphinines: besides predominant 4-alkyl-2,6-dihalobenzo[ e]-1,2-oxaphosphinines, minor 2,7- and 2,8-dihalo-substituted 4-alkylbenzo[ e]-1,2-oxaphosphinines are formed. An unusual thermal isomerization of 4-alkyl-2-fluorobenzo[ e]-1,2-oxaphosphinines to 4-alkylidene-2-fluoro-3,4-dihydrobenzo[ e]-1,2-oxaphosphinines was discovered. Molecular and supramolecular structures of some 4-alkylbenzo[ e]-1,2-oxaphosphinines were studied by X-ray diffraction analysis. [ABSTRACT FROM AUTHOR]

By 31P, 13C, 13C-{1H}, and 1H NMR spectroscopy the chlorination of 4-and 5-methyl-2,2,2-trichlorobenzo-1,3,2-dioxaphosphols was shown to provide in quantitative yield 4-methyl-2,2,2,5-tetrachloroand 6-methyl-2,2,2,5-tetrachlorobenzo-1,3,2-dioxaphosphols. Their hydrolysis led to the formation of difficultly available 4-methyl-5-chloro-and 3-methyl-4-chloro-1,2-dihydroxybenzenes. The structure of the latter compound was established by XRD analysis. The 5-methyl-2-chlorobenzo-1,3,2-dioxaphosphol treated with excess chlorine was converted in succession into 5-methyl-2,3,4,5,6,6-hexachlorocyclohex-1-en-3-yl dichlorophosphate and 5-methyl-1,2,4,4,5,6-hexachlorocyclohex-1-en-3-yl dichlorophosphate. The hydrolysis resulted in 5-methyl-2,3,4,5,6,6-hexachlorocyclohex-2-en-1-yl dihydrophosphate. The configuration of three chiral carbon atoms in the latter was established by XRD study. In the course of the chlorination the aromaticity of the ortho-phenylene fragment was distorted and 3,3-sigmatropic shift of the dichlorophosphoryl group occurred. The reaction with chlorine of 5- tert-butyl-2,2,2-trichlorobenzo-1,3,2-dioxaphosphol and 2,2,2-trichloro-benzo-1,3,2-dioxaphosphol was not selective: The reaction product obtained in excess chlorine transformed on hydrolysis into tetrachloropyrocatechol. Its solvates with water and dioxane were studies by XRD analysis. [ABSTRACT FROM AUTHOR]

It was shown for the first time that 3-chloro-, 3-bromo-, and 3-iodopropynes can react with 2,2,2-trichloro-, 2,2,2-trichloro-5-methyl-, and 5,6-dibromo-2,2,2-trichloro-1,3,2λ5-benzodioxaphospholes to give derivatives of 4-(halomethyl)-2-chloro-2 H-1,2λ5-benzoxaphosphinin-2-ones. The reaction involves nonselective chlorination of the phenylene substituent in different positions, and the resulting isomer ratio is temperature-dependent. In the reactions of 3-bromo-and 3-iodopropynes with 2,2,2-trichloro-1,3,2λ5-benzo-dioxaphosphole, a side process takes place, viz. nucleophilic substitution of bromine and iodine with chlorine. The structure of some of the prepared 4-(chloromethyl)-1,2-benzoxaphosphinines was studied by means of X-ray diffraction. [ABSTRACT FROM AUTHOR]

NMR and IR spectroscopy and X-ray diffraction were used to show that the reaction of 2,2,2-trichloro- and 2,2,2-tribromo-5-methylbenzo[d][1,3,2]dioxaphospholes withpara-substituted arylacetylenes proceeds with regioselective formation of 4-aryl-2-halo-7-methyl-2-oxobenzo[e][1,2]oxaphosphorines. With the trichlorophosphole, selective chlorination of the phenylene fragment in theparaposition to the endocyclic oxygen atom occurs. With the tribromophosphole, 6-bromo- and unsubstituted benzo[e][1,2]oxaphosphorines are formed as major products. The molecular and supramolecular structure of some of the obtained oxaphosphorines was studied by X-ray diffraction. [ABSTRACT FROM AUTHOR]