Phenyl dichlorophosphate

Treatment with dimethyl sulfoxide in the presence of phenyl dichlorophosphate or phosphoryl chloride converts ( + )-a-pinene (39) to (6/ ,4.S)-4-isopropenyl-l-methyl-6-chlorocyclohexene (51) in virtually quantitative yield, presumably also via the cyclobutylmethyl to pent-l-enyl cation rearrangement.164 Similarly, / -pinene (45) is converted to 4-isopropenyl-l-chloromethylcyclohexene (52), also in quantitative yield.164... 

Similar oxidation of alcohols has been carried out with dimethyl sulfoxide and other reagents317 in place of DCC acetic anhydride,318 SOy-pyridine-triethylamine,319 trifluo-roacetic anhydride,320 oxalyl chloride,321 tosyl chloride,322 chlorine,323 bromine,324 AgBF4-Et3N,325 P205-Et3N,326 phenyl dichlorophosphate,327 trichloromethyl chloroformate,328 tri-... 

Phenyl dichlorophosphate, 240 Other P-substituted-a, P-unsaturated carbonyl compounds (E)-(Carboxyvinyi)trimethylammo-nium betaine, 67... 

It provides from good to excellent yields in oxidations performed from — 10°C to room temperature267 Briefly mentioned by Liu and Nyangulu2673 as a less satisfactory activator than phenyl dichlorophosphate... 

Nyangulu267a as a less satisfactory activator than phenyl dichlorophosphate... 

Table 2.2. lists activators used less commonly for Moffatt oxidations. The following activators, namely diphosgene,262 triphosgene,263 2-chloro-1,3-dimethylimidazolinium chloride,264 l-cyclohexyl-3-(2-morpholinoethyl)-carbodiimide metho-p-toluenesulfonate,265 triphenylphosphine dibromide and dichloride,266 and phenyl dichlorophosphate,267 have been the subject of scientific monographs, in which they are proposed as suitable and convenient alternatives to more routinely used activators, and can offer improved oxidation conditions in some substrates. 

Thiol esters can be prepared directly from carboxylic acids by reaction with thiols in the presence of phenyl dichlorophosphate as the activating agent (equation I).s... 

Dethioacetalization. The combination of phenyl dichlorophosphate, QH5OPOCI2, and Nal converts acetals to the corresponding aldehyde or ketone, but has little, if any, effect on thioacetals. However, the reagent obtained by addition of DMF converts thioketals into the corresponding carbonyl compound at room temperature in 1-17 hours in 70-95% yield. 

Acyl azides,1 These azides are prepared in almost quantitative yield by reaction of a carboxylic acid or the potassium salt with phenyl dichlorophosphate, pyridine, sodium azide, and a catalytic amount of tetrabutylammonium bromide in CH2C12 at 25°. 

Phenoxyacetic acid, 361-362 Phenoxycoumarins, 1 3-Phenoxy-l-propyne, 373 Phenylacetaldehyde, 75 / Phenylbenzeneselenol, 35 Phenyl benzenethiosulfonate, 362-363 3-Phenyl-2,3-bornanediol, 363 Phenyl dichlorophosphate, 187 a-Phenylethylamine, 363-364... 

Esterification. Esters can be prepared in 70-95% yield by the reaction of an acid and an alcohol in the presence of pyridine (3 equiv.) and (CH3)2NPOCl2 (1.5 equiv.) at room temperature. Phenyl dichlorophosphate, C6H5OPOCI2 (1,847), can also be used as the activating agent, often with somewhat improved yields. However, this variation results in much lower yields in the case of penicillins. This esterification is applicable even to tertiary alcohols. 

A practical synthesis of a-amido 3-lactams uses a Dane salt (9) formed by the reaction of a methan-olic solution of the potassium salt of glycine with methyl acetoacetate (Scheme 9). The salt (9) readily reacts with a Schiff base in the presence of triethylamine and e.g. a chloroformate ester. Other activating agents such as phenyl dichlorophosphate - or phosphorus oxychloride - have also been successfully used. 

Thiol acids and thiol esters can be prepared in this manner, which is analogous to 16-57 and 16-64. Anhydridesand aryl esters (RCOOAr) are also used as substrates, but the reagents in these cases are usually HS and RS. Thiol esters can also be prepared by treatment of carboxylic acids with P4S10—PhySbO, or with a thiol RSH and either polyphosphate ester or phenyl dichlorophosphate PhOPOCl2. Esters RCOOR can be converted to thiol esters RCOSR by treatment with trimethylsUyl sulfides MeySiSR and AlCls- ... 

Reaction of carboxylic acids with phenyl dichlorophosphate, followed by the addition of bensenesele-nol to the mixture afforded selenol esters (Scheme 4). The reaction is assumed to proceed via the penta-covalent oxyphosphorane intermediates (11a) and (11b). 

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