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The interaction of 2-(5-methyl-2-phenyl-2H-1,2,3-diazaphosphol-4-yl)-4H-benzo[e]-1,3,2-dioxaphosphinin-4-one with mesoxalic and trifluoropyruvic acids ethyl and diethyl esters, hexafluoroacetone and chloral proceeds with an exclusive participation of P(III) atom and allows to obtain 2-(5-methyl-2-phenyl-2H-1,2,3-diazaphosphol-4-yl)-derivatives of 1,4,2- and 1,3,2-dioxaphosphepines as well as dichlorovinylphosphonate, being the product of Perkow reaction in the case of chloral. [ABSTRACT FROM AUTHOR]

ABSTRACT The synthesis of a novel mixed valence P-ligand system (II/I) with a PP bond bearing phosphonite and PH phosphanyl subunits was achieved via the reaction of a Li/Cl phosphinidenoid complex with a phosphite-substituted ketone. Density functional theory (DFT) calculations provide insight into bonding features of the novel R(H)PP(OR′)2 ligand system and its tautomer RP = PH(OR′)2. Wiberg bond index, Mayer bond order, and electron density at bond critical points are reported for both the free and ligated forms, pointing to a high degree of PP double bond character of the free ligand with a significant bond order decrease in end-on pentacarbonyltungsten complexation. [ABSTRACT FROM AUTHOR]

An Li/Cl phosphinidenoid complex, obtained by chlorine/lithium exchange from a [dichloro(organo)phosphane]tungsten(0) complex, reacted with aliphatic dicarbonyl derivatives to provide oxaphosphirane complexes, a 1,3,2-dioxaphosphol-4-ene complex, and a P-alkoxyphosphane complex; the latter is formally derived from the enol form of the β-diketone. DFT calculations on the ring-expansion rearrangement support a preferred mechanism involving a pericyclic [1,3] shift of the phosphorus fragment in an oxaphosphirane complex rather than a stepwise diradical or ionic mechanism. The latter is slightly unfavored (ΔΔ E‡ = 2.2 kcal/mol) and involves heterolytic P-C bond cleavage to give a methylene oxonium phosphanide intermediate and cyclization through a low-lying transition state featuring an unusual linear C-O-P geometry. [ABSTRACT FROM AUTHOR]

Reaction of Li/Cl phosphinidenoid pentacarbonyltungsten(0) complexes 2a,b (R = CH(SiMe3)2, Cp*) with bifunctional phosphite-substituted ketone 3 yielded tungsten complexes 4a,b having a novel mixed-valence polycyclic P,C-cage ligand with a P–P bond. DFT calculations provide insight into an unusual product formation pathway. [ABSTRACT FROM AUTHOR]

2-(5-Methyl-2-phenyl-2Н-1,2,3-diazaphosphol-4-yl)-4H-benzo[d]-1,3,2-dioxaphosphorin-4-one1readily reacts with hexafluoroacetone, mesoxalic acid diethyl ester, trifluoropyruvic acid ethyl ester and chloral to give 2-(5-methyl-2-phenyl-2H-1,2,3-dizaphosphole-4-yl)-derivatives of 1,3,2- and 1,4,2-dioxaphosphepines. [ABSTRACT FROM PUBLISHER]