49595-63-3Relevant articles and documents
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Bartlett,P.D. et al.
, p. 6486 - 6487 (1973)
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Reaction of Tetramethyl-1,2-dioxetane with Phosphines: Deuterium Isotope Effects
Baumstark, Alfons L.,Vasquez, Pedro C.
, p. 793 - 798 (2007/10/02)
The reaction of tetramethyl-1,2-dioxetane (1) in C6D6 with methyldiphenylphosphine (2a), methyl-d3-diphenylphosphine (2d), dimethylphenylphosphine (2c), and dimethyl-d6-phenylphosphine (2d) produced the corresponding 2,2-dihydro-4,4,5,5-tetramethyl-2,2,2-trisubstituted-1,3,2-dioxaphospholanes 3a-d in 90percent yield or better.The phosphoranes were characterized by 1H and 31P NMR spectroscopy and by their thermal decomposition (60 deg C) to tetramethyloxirane and the corresponding phosphine oxides .Kinetic studies of the rate of phosphorane formation in benzene were carried out by the chemiluminescence method.The reaction was found to be of the first order with respect to 1 and to the phosphines.Inverse deuterium isotope effects were observed for the reaction of 1 with phosphines 2a-d.The value of kCH3/kCD3 obtained with phosphines 2a,b was found to be 0.94 +/- 0.01 while that with phosphines 2c,d was found to be 0.91 +/- 0.01.The rates of phosphorane formation for the reaction of tetramethyl-d12-1,2-dioxetane (1d) with 2a,c and triphenylphosphine were also investigated and compared to those for reaction with 1.For all three phosphines, the rate constants with 1d were slower than those obtained with 1 (kH / kD = 1.06 +/- 0.02).This result is in marked contrast with the results obtained with the deuterated phosphines.The results are consistent with a converted insertion of the phosphine into the peroxy bond of the dioxetane.
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.
