J. Mikolajczak

Reaction of oxophosphoranesulphenyl chlorides with phosphorus trichloride : A new synthesis of dialkyl phosphorochloridothionates and their optically active analogues

Abstract The reaction of acyclic oxophosphoranesulphenyl chlorides, with phosphorus trichloride has been found to give thiophosphoryl chlorides, and phosphoryl oxychloride—the products of the exclusive deoxygenation of sulphenyl chloride. Optically active phosphonochloridothionates and phosphorochloridothionates in a high state of optical purity have been obtained with inversion of configuration from optically active sulphenyl chlorides and phosphorus trichloride. It has been shown, however, that cyclic oxophosphoranesulphenyl chlorides undergo simultaneous desulphurisation and deoxygenation when treated with phosphorus trichloride. Using cis- and trans-isomers of 2-chlorothio-4-methyl-1,3,2-dioxaphosphorinan-2-one it has been demonstrated that deoxygenation is accompanied by inversion, whereas desulphurisation occurs with retention at phosphorus. The mechanism of the title reaction is discussed.

Pentacovalent intermediate in the Arbuzov reaction

Direct evidence by 31P-n.m.r. spectroscopy is presented for the formation of a five-co-ordinate intermediate in the Arbuzov reaction of tervalent phosphorus esters with elemental chlorine or elemental bromine and benzenesulphenyl chloride.

Five-co-ordinate and phosphonium intermediates in reactions of phosphorus thionesters, >P(S)OR, with elemental chlorine and sulphuryl chloride

The results of stereochemical and product studies on the chlorination of phosphorus thionesters are rationalized in terms of phosphonium and five-co-ordinate intermediates which in the case of thionophos-phonates and cyclic five-membered thionophosphates undergo nucleophilic ligand exchange.xs

Reactions of trico-ordinate phosphorus compounds with phosphorus pseudohalogens. Part 2. Pentaco-ordinate intermediates in the reaction of o-phenylene neopentyl phosphite with diethoxyoxophosphoranesulfenyl chloride

Reaction between oxophosphoranesulfenyl chloride 1(R = R′= EtO) and o-phenylene neopentyl phosphite 4 takes predominantly the deoxygenation course, yielding the phosphorochloridothioate 7 and the phosphate 8. Formation of minor products 5 and 6 corresponding to the desulfurization pathway, and low-temperature 31P NMR observations, are rationalized by proposing phosphoranephosphonium equilibria which are shifted towards phosphorane structures 9, 13, 11. These results supplement our earlier studies on desulfurization and deoxygenation of compound 1 with tricoordinate phosphorus compounds and add new evidence for phosphonium–phosphorane equilibria.

Stereochemistry of desulphurisation and deoxygenation of oxophosphoranesulphenyl chlorides by trivalent phosphorus compounds

The ratio of desulphurisation to deoxygenation of oxophosphoranesulphenyl chlorides, >P(O)SCI, by trivalent phosphorus compounds depends on the nature of the PIII compounds and is accompanied by inversion of configuration at the chiral phosphorus atom of the sulphenyl chloride.