Hydroxysulfenylation of olefins. An olefin cleavage with functional group differentiation

Trost, Barry M.; Ochiai, Masahito; McDougal, Patrick G.

doi:10.1021/ja00490a072

Cited by 66 publications

(31 citation statements)

References 1 publication

(1 reference statement)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Furthermore, the Markovnikov regioselectivity 3/4 for the reaction using Pd(OAc) 2 is unusually decreased on dilution with a polar solvent (MeCN or MeNO 2 ) while that using AgOAc is increased on dilution with MeNO 2 (Table 3). These data show that the reaction using Pd(OAc) 2 does not proceed via a thiiranium ion, and thus this action for Pd(OAc) 2 can be ruled out. Another action is coordination.…”

Section: Formation Of Thiiranium Radical Cations II and Ii' From Sulfmentioning

confidence: 83%

“…As an oxidant Pd(OAc) 2 can act in two ways. The first action is electron transfer: One electron transfer from 1 to Pd(OAc) 2 forms a disulfide radical cation [7], and the radical cation and/or a sulfenium ion [8] arising from the radical cation should generate a thiiranium ion as the final intermediate by attack on the alkene.…”

Section: Formation Of Thiiranium Radical Cations II and Ii' From Sulfmentioning

confidence: 99%

“…The first action is electron transfer: One electron transfer from 1 to Pd(OAc) 2 forms a disulfide radical cation [7], and the radical cation and/or a sulfenium ion [8] arising from the radical cation should generate a thiiranium ion as the final intermediate by attack on the alkene. As seen in Tables 1 and 4, the reaction using Pd(OAc) 2 shows higher Markovnikov regioselectivity (3b/4b = 0.44) at 25°C than that observed at 25°C (0.27) in the reaction via a thiiranium ion [9] using AgOAc instead of Pd(OAc) 2 . Furthermore, the Markovnikov regioselectivity 3/4 for the reaction using Pd(OAc) 2 is unusually decreased on dilution with a polar solvent (MeCN or MeNO 2 ) while that using AgOAc is increased on dilution with MeNO 2 (Table 3).…”

Section: Formation Of Thiiranium Radical Cations II and Ii' From Sulfmentioning

confidence: 99%

“…We may infer that the reactions of RSCl with alkenes would generate not a σ-sulfurane but a strongly bridged thiiranium ion pairing tightly with hard Cl − [1], and thus the ring-opening by the pairing Cl − leads to the anti-Markovnikov regioselectivity without undergoing the stereoconversion and skeletal rearrangement. In this work, reactions of dimethyl disulfide with 2-alkyl and 2,2-dialkylalkenes in AcOH in the presence of Pd(OAc) 2 lead to the anti-Markovnikov and Markovnikov regioselectivity products, respectively, for the addition to the alkenes. Interestingly, the Markovnikov regioselectivity is lower than that observed for thiiranium ion intermediates, and is decreased by addition of polar solvents such as MeCN or MeNO 2 or the nonpolar solvent n-hexane.…”

Section: Introductionmentioning

confidence: 97%

“…Thiiranium ion intermediates have been generated by reactions of disulfides with alkenes in the presence of oxidants such as Pb(OAc) 4 [1][2][3][4], Mn(OAc) 3 [2][3][4], Fe(OAc) 3 [2][3][4] or Cu(OAc) 2 [5], by reactions of β-thiohalides with AgY [6] and by reactions of thiiranes with RY [6]. The intermediates which have soft counterions such as BF 4 − , PF 6 − , SbF 6 − , SbCl 5 − , FSO 3 − and CF 3 CO 2 − behave like carbenium ions [1] of a weakly bridged strong electrophile, undergoing a rapid ring-opening by the outer nucleophile at low temperature (−20-0 o C) to give the observed predominant Markovnikov regioselectivity; in some cases, the skeletal rearrangement or stereoconversion of the thiiranium ions has been observed.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

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

2000

View full text Add to dashboard Cite

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.

show abstract

Section: Formation Of Thiiranium Radical Cations II and Ii' From Sulfmentioning

confidence: 83%

Section: Formation Of Thiiranium Radical Cations II and Ii' From Sulfmentioning

confidence: 99%

Section: Formation Of Thiiranium Radical Cations II and Ii' From Sulfmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 97%