Thiiranium Ions as Reaction Intermediates

Mueller, W. H.

doi:10.1002/anie.196904821

Cited by 88 publications

(25 citation statements)

References 57 publications

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“…An investigation of the kinetics and NMR spectroscopy of the reactions of methyl and 2,4-dinitrobenzenesulfenyl chlorides with cyclohexene are consistent with σ -type tetracovalent sulfur of the cyclic episulfonium intermediates [7]. In addition, experimental results reported for the reactions of 2,4-dinitrobenzenesulfenyl chloride with styrene and propylene reflect carbonium ion character in the transition structures [5].…”

Section: Introductionmentioning

confidence: 71%

DFt study of the regioselectivity of addition of sulfenylchloride to ethenes

Vektarienė

Vektaris

Rankin

2007

Heteroatom Chemistry

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Section: Introductionmentioning

confidence: 71%

DFt study of the regioselectivity of addition of sulfenylchloride to ethenes

Vektarienė

Vektaris

Rankin

2007

Heteroatom Chemistry

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“…[4][5][6][7] The ratios of the amounts of the two isomers formed are believed to result from competition between steric and electronic effects of thiiranium intermediate. [5][6][7] Despite the extensive research that has been carried out on electrophilic addition to olefins, theoretical protocol for encompassing mechanism of this class reactions is still not available. Much of the discussions of the mechanisms involve reaction energetics and transition state studies 8 while little effort has been expended on a molecular orbital approach to these problems.…”

Section: Methodsmentioning

confidence: 99%

Quantum chemical study of the thiiranium ion intermediates and regioselectivity features of the halogenide addition

Vektarienė¹,

Vektaris²

2006

Arkivoc

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Electrophilic addition reactions of the methyl sulfide cation to series of substituted ethenes leading to thiiranium intermediate formation followed by further nucleophilic attack of the chloride anion have been studied by means of ab initio Hartree-Fock calculations at the 6-311+G level. The electronic states of differently substituted thiiranium intermediate structures were investigated, in order to get more insight into the nature of the experimentally observed regioselectivity of nucleophilic attack of the chloride anion on the C(α) or C(β) carbon atoms with different substituents on α-carbon of thiiranium intermediate. The regularities obtained in these calculations are shown to correlate well with experimental data. The quantum chemical estimation for this key reaction may be useful for experimental organic chemist in their future synthetic studies to predict structures of supposed new products for this reaction.

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“…According to the molecular model, the S-atom of IId and II'd is closer to the 2-methyl carbon than that of IIc and II'c, so IId and II'd may rearrange to the thietanium radical cations IIId and III'd by a concerted reaction involving C 2 -S bond breaking and hydride migration of the 2-methyl group, leading to 5d (Scheme 3). A similar anionotropic rearrangement from thiiranium ion to thietanium ion has been proposed for the concerted reaction involving C 2 -S breaking and methyl migration at tertiary carbon [10][11][12][13][14]. …”

Section: Reactions With 1-methylcyclohex-1-ene (2d)mentioning

confidence: 64%

Novel Behavior of Thiiranium Radical Cation Intermediates. Reactions of Dimethyl Disulfide with Alkenes in the Presence of Pd(OAc)2

2000

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Reaction of dimethyl disulfide (1) with cyclohexene (2a) in AcOH in the presence of Pd(OAc) 2 yields trans-1-acetoxy-2-methylcyclohexane (3a). The equivalent reactions with hex-1-ene (2b) and 2-methylpent-1-ene (2c) or 1-methylcyclohex-1-ene (2d) preferentially give anti-Markovnikov and Markovnikov adducts 4 and 3, respectively, by acetoxymethylthiolation of the alkene. The Markovnikov regioselectivity 3b/4b for the reaction with 2b is higher than that for the reaction using AgOAc instead of Pd(OAc) 2, which proceeds via a thiiranium ion. Addition of a polar solvent (MeCN or MeNO 2 ) to the reactions with 2b or 2c using Pd(OAc) 2 abnormally decreases the Markovnikov regioselectivity. The total yield of 3 and 4 increases with an increased concentration of AcOH. Compounds 3 and 4 are also formed and the reactions in MeCN or MeNO 2 not containing AcOH. A solution of Pd(OAc) 2 in 1 exhibits λ max 380 nm (log ε 3.6) assigned to the absorption of a relatively stable sulfonium salt. These indicate that the reactions using Pd(OAc) 2 proceed by S N 2 ringopening of a new type of thiiranium radical cations paired with − OAc via the sulfonium salts. The insensitivity of the 3/4 ratios to the reaction time at 25-60°C in the reactions with 2c-d shows the ring-opening to be controlled kinetically, but the increased ratio with reaction time at 116°C in the reaction with 2b suggests that the ring-opening is thermodynamically governed. The reaction product with 2d also undergoes a skeletal rearrangement to a thietanium radical cation to give 1-acetoxymethyl-2-methylthiocyclohexane.

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Thiiranium Ions as Reaction Intermediates

Cited by 88 publications

References 57 publications

DFt study of the regioselectivity of addition of sulfenylchloride to ethenes

DFt study of the regioselectivity of addition of sulfenylchloride to ethenes

Quantum chemical study of the thiiranium ion intermediates and regioselectivity features of the halogenide addition

Novel Behavior of Thiiranium Radical Cation Intermediates. Reactions of Dimethyl Disulfide with Alkenes in the Presence of Pd(OAc)2

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