Arylphosphonic dichlorides

Miles, J.A., Beeny, M.T., and Ratts, K.W., A general route to methoxy-substi-tuted arylphosphonous dichlorides via mild Lewis acid catalysis, /. Org. Chem., 40, 343, 1975. 

The esters of arylphosphonic acids are cleaved to the acids by HC1, HBr, or HI.9b Arylphosphonic dichlorides (ArPOCl2) are easily converted to esters by reaction with the alcohol in pyridine solution.10... 

Arylphosphonic acid derivatives, 58, 137 Arylphosphonic dichlorides, 58, 136 Aryltetrachlorophosphoranes, 58, 137 L-Asparagine, carbobenzoxy-, 56, 89 L-Asparagine, NJ-(tnfluoroacetyl)- 56, 125 L ASPARAGINYL-L-LEUCINE, CARBOBENZOXY-,METHYL ESTER, 56, 88 Z-Asp Gly-OEt, 56, 93 (l-Azido-3,3-dimethoxy-l-propenyl)ben-zene, 57, 84... 

Another surprisingly stable compound containing a P=P bond has been isolated. Reaction of the sterically hindered arylphosphonic dichloride (6) with magnesium gives the crystalline diphosphene oxide (7), which, not surprisingly, is rapidly hydrolysed by water. The tris(diphenylthiophosphinoyl)meth-anide (8) has been isolated as its tetra-n-butylammonium salt. ... 

The mode of reaction of alkyl- or arylphosphonic halides with Grignard reagents in ether is most often unpredictable. Bis(p-tolyl)phenyl-phosphine oxide is reported as the major product from phenylphos-phonic dichloride and the required quantity of Grignard reagent (148). Attempted synthesis of diallylphenylphosphine oxide under similar circumstances gave only undistillable black oils and tars (13). Equimolar quantities of reactants furnished diphenylphosphinic acid in good yield plus a small quantity of triphenylphosphine oxide (45). 

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