Intramolecular alkylation of 3- and 4-halogenoalkyldiphenylphosphine sulfides. Ring-chain halogenotropic tautomerism of 2,2-diphenyl-l,2λ4-thiaphospholanium and 2,2-diphenyl-l,2λ4-thiaphosphorinanium iodides

N-alkylation of amidothiophosphoryl compounds under phase-transfer catalysis conditions. Synthesis and properties of 1,3,2-thiazaphosphacyclanes

“…The spectroscopic characteristics of com pounds 6a and 5a-c are closely related to those of struc turally similar cyclic compounds. 6, 16 Hydrolysis of thiazaphospholanium perchlorate 6b and thiazaphosphinanium perchlorate 6c gives diphenyl phosphinic acid as a sole phosphorus containing product, regardless of the ring size and the hydrolysis medium (basic or acid) (Scheme 8). Therefore, the hydrolysis results in cleavage of both the P-S and P-N bonds, the ring opening being com pleted within 15-20 min.…”

Synthesis, some properties and structural features of 1,2-thiaphosphacyclanes

“…It was also established that the proportion of the cyclic tautomer A increases with a decrease in temperature, 80,81 i.e., as in other ring-chain tautomeric systems, 102 the transition of a cyclic form into the linear one is an endothermic process.…”

“…For the first time, this reaction has been employed for the synthesis of 2,2-diphenyl-1,2l 4 -thiaphosphacyclanium iodides 103a,b (E = S, n = 3, 4; Hal = I), which were obtained by refluxing solutions of the thermally stable o-chloroalkyldiphenylphosphine sulfides 104a,b in either acetone or acetonitrile with NaI. 80 The reaction proceeds via the formation of the corresponding o-iodoalkyldiphenylphosphine sulfides 105a,b, which was confirmed by 31 P NMR spectroscopy. In contrast to o-chloro-substituted derivatives 104a,b, o-bromoalkylphosphine sulfides 106a,b, obtained from the corresponding hydroxy derivatives 107a,b and isolated in a pure state, underwent rather easy transformations into cyclic thiaphosphacyclanium bromides 103a,b (Hal = Br) (heating at 100 8C without a solvent).…”

“…102 For the first time, the existence of such a tautomeric equilibrium A > B was detected for 2,2-diphenyl-1,2l 4 -thiaphospholanium iodides (103a, Hal = I) and 2,2-diphenyl-1,2l 4 thiaphosphinanium iodides (103b, Hal = I). 80 However, halogenotropic tautomerism in the series of 1,2-thiaphosphacyclanium salts was investigated in more detail by the example of the corresponding bromides, both the linear (106a,b) and the cyclic (103a,b) tautomers of which (Hal = Br) were isolated in the pure state and investigated by X-ray diffraction analysis. 80,81 It was shown that the equilibrium position is attained starting from either the linear or cyclic tautomer.…”

“…80 However, halogenotropic tautomerism in the series of 1,2-thiaphosphacyclanium salts was investigated in more detail by the example of the corresponding bromides, both the linear (106a,b) and the cyclic (103a,b) tautomers of which (Hal = Br) were isolated in the pure state and investigated by X-ray diffraction analysis. 80,81 It was shown that the equilibrium position is attained starting from either the linear or cyclic tautomer. Thus, according to the 31 P NMR data, keeping a solution of a five-membered cyclic bromide 103a (Hal = Br) (or its linear tautomer 106a) in CH 2 Cl 2 at 20 8C yields an equilibrium mixture of the same composition comprising 38% of the cyclic (A) and 62% of the linear (B) tautomer.…”