메뉴 건너뛰기




Volumn 68, Issue 3, 2003, Pages 811-823

Novel pathways for oxygen insertion into unactivated C-H bonds by dioxiranes. Transition structures for stepwise routes via radical pairs and comparison with the concerted pathway

Author keywords

[No Author keywords available]

Indexed keywords

FREE RADICALS; HYDROGEN BONDS; PROBABILITY DENSITY FUNCTION;

EID: 0037423178     PISSN: 00223263     EISSN: None     Source Type: Journal    
DOI: 10.1021/jo0266184     Document Type: Article
Times cited : (36)

References (64)
  • 13
    • 0348086812 scopus 로고    scopus 로고
    • note
    • 2 = 0.378). In this paper the authors stressed that UB3LYP calculations correctly describe the homolytic cleavage of O-O peroxy bond with results "in good agreement with MR-AQCC results".
  • 16
    • 0347456844 scopus 로고    scopus 로고
    • note
    • z nonbonding orbitals of the oxygen atoms.
  • 17
    • 0346826049 scopus 로고    scopus 로고
    • note
    • (b) Ring opening is accompanied by a formal rotation of the two 2p π electron pairs at the O atoms into the OCO plane.
  • 18
    • 0346826048 scopus 로고    scopus 로고
    • note
    • 10 have described the radical intermediate 3-Me, but they only considered the less stable conformer (anti-3-Me). Overlooking the more stable conformer can lead, owing to the sizable difference in energy between the two forms, to wrong evaluation of activation and reaction free energy of reactions that involve this species.
  • 19
    • 0035860995 scopus 로고    scopus 로고
    • Fokin, A. A.; Tkachenko, B. A.; Korshunov, O. I.; Gunchenko, P. A.; Schreiner P. S. J. Am. Chem. Soc. 2001, 123, 11248. This paper reports the reaction of DMD with highly strained carbon-carbon single bonds that goes through a diradicaloid TS with formation of a diradical intermediate that then fragments to afford the final products.
    • (2001) J. Am. Chem. Soc. , vol.123 , pp. 11248
    • Fokin, A.A.1    Tkachenko, B.A.2    Korshunov, O.I.3    Gunchenko, P.A.4    Schreiner, P.S.5
  • 37
    • 0347456843 scopus 로고    scopus 로고
    • note
    • 17a we did not perform energy correction by removing spin contamination. This might mean that the "true" energy of diradicaloid TSs is slightly lower than that here reported.
  • 43
    • 0346195438 scopus 로고    scopus 로고
    • note
    • Specific and bulk solvation have no appreciable effect on geometry and does not improve wave function stability of TS conc-5a. Also the wave function of concerted TS for the reaction of methyl-(trifluoromethyl)dioxirane with methane was found to be instable (see the Supporting Information).
  • 44
    • 0030768537 scopus 로고    scopus 로고
    • "Molecule induced homolysis" or "molecule induced radical formation" indicate a process in which a radical pair is formed by reaction between two closed shell molecules. Rüchardt, C.; Gerst, M.; Ebenhoch, J. Angew. Chem., Int. Ed. Engl. 1997, 36, 1406.
    • (1997) Angew. Chem., Int. Ed. Engl. , vol.36 , pp. 1406
    • Rüchardt, C.1    Gerst, M.2    Ebenhoch, J.3
  • 49
    • 0348086801 scopus 로고    scopus 로고
    • note
    • 1,2 One can reasonably argue that their decomposition should be faster than their formation, however, as suggested by a referee, further careful control experiments are in order given that this point is critical for the "perpedicular" mechanism.
  • 50
    • 0346195440 scopus 로고    scopus 로고
    • note
    • 4 During such a short time the two radicals must reorient and their radical centers must approach to each other at a distance of ≊ 3 Å so that bonding can begin. This task might probably be achieved only if the energy delivered on the descent from the TS concentrates in the appropriate degree of freedom.
  • 51
    • 0348086807 scopus 로고    scopus 로고
    • note
    • 1 = 1.371 Å).
  • 53
    • 0346195439 scopus 로고    scopus 로고
    • note
    • For example, as suggested by a reviewer, the energy minimum that corresponds to the radical pair might be the result of an overestimation of its stability by the UB3LYP method.
  • 54
    • 0347456839 scopus 로고    scopus 로고
    • note
    • 34b that of a one step (that is, without intermediates) borderline between concerted and non concerted mechanism.
  • 57
    • 0346826044 scopus 로고    scopus 로고
    • note
    • 37 Consequently in a mechanism with the 1 → 2 ring opening followed by the attack of 2 on alkane, the former unimolecular reaction would be the rate determining step in striking contrast with the observed second-order kinetics and isotope effects.
  • 59
    • 0346195437 scopus 로고    scopus 로고
    • note
    • One should remember that IRC traces the minimum energy path and not real trajectories. Consequently, it is not surprising that IRC following from TS rad,perp-5 (the dioxirane moiety of which exhibits a geometry very similar to that of 2) toward the reactants moves along the path that involves minor electronic and geometric changes, namely that one leading to 2 plus methane. Only molecular dynamic studies can probably shed light on the possible direct origin of TS rad,perp from reactants.
  • 61
    • 0346195429 scopus 로고    scopus 로고
    • note
    • 2a
  • 62
    • 0346195430 scopus 로고    scopus 로고
    • note
    • 2b A referee suggested that reaction of secondary C-H bond could represent an artifact due to the onset of radical DMD decomposition over the long reaction times. As a rule, e.g., reactions of DMD with 1,2-dimethylcyclohexanes and decalins, only attack at the tertiary C-H was observed.
  • 63
    • 0346195428 scopus 로고    scopus 로고
    • note
    • acetone = 22.24.
  • 64
    • 0348086798 scopus 로고    scopus 로고
    • note
    • 13 have already emphasized, by studying the reaction of DHD with acetaldehyde (as model for acetone), that the presence of acetone as solvent is compatible with the concerted mechanism.


* 이 정보는 Elsevier사의 SCOPUS DB에서 KISTI가 분석하여 추출한 것입니다.