73116-90-2Relevant academic research and scientific papers
Reaction of Tetramethyl-1,2-dioxetane with Triphenylphosphine: Activation Parameters for the Formation of 2,2-Dihydro-4,4,5,5-tetramethyl-2,2,2-triphenyl-1,3,2-dioxaphospholane
Baumstark, Alfons L.,Barrett, Morgan,Kral, Kathleen M.
, p. 201 - 203 (2007/10/02)
The reaction of tetramethyl-1,2-dioxetane (1) and triphenylphosphine (2) in benzene-d6 produced 2,2-dihydro-4,4,5,5-tetramethyl-2,2,2-triphenyl-1,3,2-dioxaphospholane (3) in about 90percent yield over the temperature range 6-60 deg C.Pinacolone and triphenylphosphine oxide (4) were the major side products .Thermal decomposition of 3 produced only 4 and 5.Kinetic studies were carried out by the chemiluminescence method.The rate of phosphorane was found to be first order with respect to each reagent.The activation parameters for the reaction of 1 and 2 were: Ea = 9.8+/-0.6 kcal/mole; ΔS = -28 eu; k30 deg C = 1.8 m-1sec-1 (range = 10-60 deg C).Preliminary results for the reaction of 1 and tris(p-chlorophenyl)phosphine were Ea about 11 kcal/mol, ΔS = -24 eu, k30 deg C = 1.3 M-1sec-1 while those for the reaction of 1 and tris(p-anisyl)phosphine were: Ea about 8.6 kcal/mol, ΔS = -29 eu k30 deg C = 4.9 M-1sec-1.
Reaction of Triarylphosphines with Tetramethyl-1,2-dioxetane: Kinetics of Formation and Decomposition of 2,2-Dihydro-4,4,5,5-tetramethyl-2,2,2-triaryl-1,3,2-dioxaphospholanes
Baumstark, Alfons L.,McCloskey, Candice J.,Williams, Timothy E.,Chrisope, Douglas R.
, p. 3593 - 3597 (2007/10/02)
The reaction of a series of triarylphosphines with tetramethyl-1,2-dioxetane (1) in C6D6 produced a series of 2,2-dihydro-4,4,5,5-tetramethyl-2,2,2-triaryl-1,3,2-dioxaphospholanes in high yield.Thermal decomposition of the phosphoranes produced tetramethylethylene oxide and the corresponding triarylphosphine oxides in all cases.The kinetics of phosphorane formation and decomposition in benzene was investigated.The rate data for phosphorane formation showed a reasonable correlation with ?+ constants (correlation coefficient ca 0.98: ρ = -0.82).Theresults are not consistent with nucleophilic attack on oxygen by phosphorus but rather with a concerted (biphilic) insertion into the peroxy bond of the dioxetane.Phosphorane decomposition (at 38 deg C) was found to be substantially more sensitive to substituent effects than phosphorane formation.A good correlation of phosphorane decomposition with Hammett ? constants was obtained (correlation coefficient = 0.997, ρ = -3.51 +/- 0.24).This result is consistent with a mechanism that involves heterolytic cleavage of a phosphorus-oxygen bond followed by the irreversible internal displacement of triarylphosphine oxide.
