Benzene phosphonous dichloride

The reaction of 2-deoxy-3,4,6-tri-0-methyl-2-methylamino-D-glucopyranose 149 with methyl(phenyl)phosphonic dichlorides (106a-b) or methylthiophosphonic dichloride in benzene in the presence of triethylamine afforded mixtures of four isomers of the corresponding 1,3,2 oxazaphospholidine-2-ones 150, 151 and... 

Another important source of chiral auxiliaries for the synthesis of optically active phosphorus derivates are the C2 symmetric diamines such as 1,2-diaminocyclohex-anes. In 1994, Hanessian and co-workers described the use of A,/V -dimethyl-(R,R)-1,2-diaminocyclohexane 93 as a chiral auxiliary in the synthesis of optically pure or enantiomerically enriched a-alkyl a-amino phosphonic acids [49], Starting from easily accessible optically pure diamine 93, they synthesized in good yield (75 %) enantiomerically pure (R,R)-ethylphosphonamide 94 by condensation with ethyl phosphonic dichloride in benzene in the presence of triethylamine (Scheme 43). 

The early literature describes examples of elimination reactions of a rather forcing nature which have not been explored further. For example, the elimination of HCl from (2-chloroethyl)phosphonic dichloride occurs over BaCl2 at 330 and dechlorination of (l,2-dichloroethyl)phosphonic diesters occurs on heating with zinc dust. Dehydrochlorination of a (2-chloroalkyl)phosphonic acid occurs on simple pyrolysis but the preferred procedure consists in the treatment of the acid diester with Et3N in warm benzene, a procedure also used for analogous (2-chloroethyl)phosphinic esters ". The dehydro-halogenation of isopropyl (2-haloethyl)phenylphosphinate by a chiral tertiary amine, such as quinine, quinidine, 1 -phenylethylamine or A-methylephedrine, in a less than equivalent quantity, affords an enrichment of one enantiomer of the ethenylphenylphosphinic... 

The reaction has been extended to include buta-1,3-dienes. Thus 86 affords the phosphonic dichlorides 87 (R = H or Me) (reaction carried out in benzene with decomposition of the complex by SO2), apparently confirmed through ozonolysis to give formic acid . Conflicting reports suggest that the addition to buta-1,3-diene (but not isoprene) occurs in the presence of AC2O to give (4-chlorobut-2-enyl)phosphonic dichloride, a result... 

The addition of H2C=CHCOR (R = H or Me) or Me2C=CHCOMe to PCI5 in benzene yields dichlorophosphates in low yields however, a change in the order of mixing results in C-phosphorylation and, for example, but-3-en-2-one yields a complex which, on decomposition with acetic anhydride, gives (2-chloro-3-oxobutyl)phosphonic dichloride ... 

Benzene Phosphorous Dichloride — (i) Chemical Designations — Synonyms Phenyl Phosphonous Dichloride, Phenylphosphine Dichloride, Dichlorophenyl-phosphine Chemical Formula CsHjPClj (ii) Observable Characteristics — Physical State (as normally shipped) Liquid Color Colorless Odor Acrid and pungent (iii) Physical and Chemical Properties — Physical State at 15 C and I atm. Liquid Molecular Weight 179.0 Boiling Point at I atm. 430, 221, 494 Freezing Point -60, -51, 222 Critical Temperature Not pertinent Critical Pressure Not pertinent Specific Gravity 1.140 at 25 °C... 

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