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Volumn 131, Issue 29, 2009, Pages 10015-10022

Regioselectivity in the reductive bond cleavage of diarylalkylsulfonium salts: Variation with driving force and structure of sulfuranyl radical intermediates

Author keywords

[No Author keywords available]

Indexed keywords

ALKYL CLEAVAGE; ANTIBONDING; BOND CLEAVAGES; BOND DISSOCIATION ENERGIES; CLEAVAGE PRODUCTS; DRIVING FORCES; ELECTRON REDUCING AGENTS; EXCITED SINGLET STATE; INDIRECT ELECTROLYSIS; ONE-ELECTRON REDUCTIONS; ORBITALS; PRODUCT RATIOS; REDUCTANTS; REDUCTIVE CLEAVAGE; REGIOSPECIFIC; SULFONIUM SALTS;

EID: 67651233260     PISSN: 00027863     EISSN: None     Source Type: Journal    
DOI: 10.1021/ja809918k     Document Type: Article
Times cited : (19)

References (52)
  • 5
    • 67651224861 scopus 로고    scopus 로고
    • N2 reaction.
    • N2 reaction.
  • 34
    • 67651235316 scopus 로고
    • In one case, an intermediate sulfuranyl radical was captured by oxidation to give the corresponding sulfonium salt. See
    • In one case, an intermediate sulfuranyl radical was captured by oxidation to give the corresponding sulfonium salt. See: Leanardi, P.; Tundo, A.; Zanardi, G. J. Chem. Soc., Chem. Commun. 1985, 1390-1391.
    • (1985) J. Chem. Soc., Chem. Commun , pp. 1390-1391
    • Leanardi, P.1    Tundo, A.2    Zanardi, G.3
  • 43
    • 67651235315 scopus 로고    scopus 로고
    • DFT calculations indicated that the reduction of phenyldiethylsulfonium ion to ethyl radical and phenylethylsulfide is thermodynamically favored by 13 kcal/mol over the alternative reduction to phenyl radical and diethylsulfide
    • DFT calculations indicated that the reduction of phenyldiethylsulfonium ion to ethyl radical and phenylethylsulfide is thermodynamically favored by 13 kcal/mol over the alternative reduction to phenyl radical and diethylsulfide.
  • 44
    • 67651221843 scopus 로고    scopus 로고
    • The structures of b and c clearly predict that cleavage ratios derived from different sulfonium salts will not commute.2 Because the ratio of populations of b and c varies with the structure of the sulfonium salts, the apparent cleavage ratio is a composite of the direct competition kR1/k R2 and the population ratio [b, c, This population effect is also seen quite clearly in the reduction of cis- and trans-1-phenyl-2-methyltetrahydrothiophenium salts. 2 Because of the ring, there is no sulfuranyl radical structure in which primary and secondary alkyl groups simultaneously occupy apical positions and compete directly. Furthermore, there is no reason for the population ratio b/c to be constant for the cis and trans isomers or to relate to the primary/secondary cleavage ratio observed when acyclic phenyldialkylsulfonium salts are redu
    • 2 Because of the ring, there is no sulfuranyl radical structure in which primary and secondary alkyl groups simultaneously occupy apical positions and compete directly. Furthermore, there is no reason for the population ratio b/c to be constant for the cis and trans isomers or to relate to the primary/secondary cleavage ratio observed when acyclic phenyldialkylsulfonium salts are reduced.
  • 45
    • 67651221845 scopus 로고    scopus 로고
    • DFT calculations for 1 and 2 indicated that the reduction to give 4-tolyl radical rather than the corresponding alkyl radical is thermodynamically disfavored by 11.3 and 10.5 kcal/mol, respectively.
    • DFT calculations for 1 and 2 indicated that the reduction to give 4-tolyl radical rather than the corresponding alkyl radical is thermodynamically disfavored by 11.3 and 10.5 kcal/mol, respectively.
  • 46
    • 67651238211 scopus 로고    scopus 로고
    • The distinction between aryldialkyl and diarylalkylsulfonium salts is preserved in the reduction of cyclic sulfonium salts.2 The reduction of 1-phenyltetrahydrothiophenium cation gives only ring-opened product; phenyl cleavage is not observed. In contrast, the reduction of the benzofused system, 1-phenylthiaindan hexafluorophosphate, gives ∼15% aryl cleavage. The 1-phenylthiaindan cation is reduced to give a mixture of two nonequilibrating sulfuranyl radicals, one of which must give phenyl cleavage
    • 2 The reduction of 1-phenyltetrahydrothiophenium cation gives only ring-opened product; phenyl cleavage is not observed. In contrast, the reduction of the benzofused system, 1-phenylthiaindan hexafluorophosphate, gives ∼15% aryl cleavage. The 1-phenylthiaindan cation is reduced to give a mixture of two nonequilibrating sulfuranyl radicals, one of which must give phenyl cleavage.
  • 48
    • 67651211361 scopus 로고    scopus 로고
    • The rates of the forward and back electron transfer reactions of the sulfonium/sulfuranyl couple also depend on the nature of the redox partner. In the limit of exothermic reductions, the nature of the redox partner apparently does not have a significant effect on the relative rates k 1/k2 and k1/k2, as judged by the small variations in F. On the other hand, the nature of the redox partner may account for some of the scatter in Figure 1
    • 2, as judged by the small variations in F. On the other hand, the nature of the redox partner may account for some of the scatter in Figure 1.


* 이 정보는 Elsevier사의 SCOPUS DB에서 KISTI가 분석하여 추출한 것입니다.