Intermolecular insertion reactions of phosphoryl nitrenes

Breslow, Ronald; Feiring, Andrew E.; Herman, F.

doi:10.1021/ja00825a042

Cited by 62 publications

(39 citation statements)

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“…An intermediate active space examined included the P-N σ bonding orbital, the corresponding σ* antibonding orbital, as well as the orbitals and electrons mentioned above to form a (6,5) active space for phosphinoylnitrene and a (8,6) active space for phosphinyl-and phosphorylnitrene. The inclusion of all of these bonding orbitals, antibonding orbitals, lone pair orbitals on phosphorus, oxygen and nitrogen formed the largest active space, which was (12,10) for dimethylphosphinoylnitrene and (18,14) for dimethylphosphinyl-and dimethylphosphorylnitrene.…”

Section: Multireference Calculationsmentioning

confidence: 99%

“…These geometries were then used for starting geometries in CASSCF/6-31G(d,p) geometry optimizations. For dimethylphosphinoylnitrene, the CASSCF/6-31G(d,p) geometry optimization were performed for all of the previously mentioned active spaces ((4,3), (6,5), and (12,10)). For dimethylphosphinyl-and dimethylphosphorylnitrene, the CASSCF/6-31G (d,p) geometry optimizations were performed using the (6,4) and (8,6) active spaces.…”

Section: Multireference Calculationsmentioning

confidence: 99%

“…The inclusion of the π bond in the (12,10) active space of the phosphinoylnitrene is necessary to calculate energies similar to the CBS-QB3 results. When the phosphinoyl π bond is left out of the active space, as in the (4,3) and (6,5) cases, the energy of the closed-shell singlet is underestimated ~20 kcal mol −1 , which resulted in a significant underestimation of the singlet-triplet energy.…”

Section: Nitrene Electronic State Energiesmentioning

confidence: 99%

“…Photolysis of diphenylphosphinyl azide (4) extrudes N 2 , and in methanol, the final products of the reaction are the phosphonamidate (5) and diphenylphosphinyl amide (6). 6 The phosphonamidate 5 product forms in a reaction between methanol and a Curtius-like rearrangement product of 4 that arises in either a concerted fashion with the loss of N 2 or from the singlet nitrene.…”

Section: Introductionmentioning

confidence: 99%

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Computational Study of the Curtius-like Rearrangements of Phosphoryl, Phosphinyl, and Phosphinoyl Azides and Their Corresponding Nitrenes

et al. 2007

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The free energies of reaction (ΔG) and activation (ΔG ‡ ) were determined for the Curtius-like rearrangement of dimethylphosphinoyl, dimethylphosphinyl, and dimethylphosphoryl azides as well as the corresponding singlet and triplet nitrenes by CBS-QB3 and B3LYP computational methods. From CASSCF calculations, it was established that the closed-shell configuration was the lower energy singlet state for each of these nitrenes. The triplet states of dimethylphosphinyl-and dimethylphosphorylnitrene are the preferred ground states. However, the closed-shell singlet state is the ground state for dimethylphosphinoylnitrene. The CBS-QB3 free energy of activation (ΔG ‡ ) for the Curtius-like rearrangements of dimethylphosphinyl and dimethylphosphoryl azides was 45.4 and 47.0 kcal mol −1 , respectively. For the closed-shell singlet dimethylphosphinyl-and dimethylphosphorylnitrene, the CBS-QB3 ΔG ‡ for the rate-limiting step of the Curtius-like rearrangement was 22.9 and 18.0 kcal mol −1 , respectively. It is unlikely that the nitrenes will undergo a Curtius-like rearrangement because of competing bimolecular reactions that have lower activation barriers. The pharmacology of weaponized organophorphorus compounds can be investigated using phosphorylnitrenes as photoaffinity labels. Dominant bimolecular reactivity is a desirable quality for a photoaffinity label to possesses, and thus, the resistance of phosphorylnitrenes to intramolecular Curtius-like rearrangements increases their usefulness as photoaffinity labels.

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Section: Multireference Calculationsmentioning

confidence: 99%

Section: Multireference Calculationsmentioning

confidence: 99%

Section: Nitrene Electronic State Energiesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Computational Study of the Curtius-like Rearrangements of Phosphoryl, Phosphinyl, and Phosphinoyl Azides and Their Corresponding Nitrenes

et al. 2007

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“…It is known that upon photolysis, phosphoryl azides can generate phosphorylnitrenes, which can insert into unactivated C-H bonds. 8,9,10 Subsequently, the photochemistry of DPP-N 3 was studied by laser flash photolysis (LFP) and electron paramagnetic resonance (EPR) methods. 11,12 Although triplet phosphorylnitrene has been detected by Gohar and Platz 12 using nanosecond LFP techniques, the shorter lived reactive singlet ( 1 DPP-N) analogue has not been spectroscopically observed.…”

Section: Introductionmentioning

confidence: 99%