Additions to alkenes via metal ion-promoted oxidation of dialkyl and diaryl disulphides

Bewick, A.; Mellor, John M.; Owton, W. Martin

doi:10.1039/p19850001039

Cited by 30 publications

(9 citation statements)

References 4 publications

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“…An addition of Cu(OAc) 2 to the reaction with 2b using Pd(OAc) 2 resulted in rather suppressed yields of 3b and 4b (Tables 1 and 4). The use of Cu(OAc) 2 , Mn(OAc) 3 or Pb(OAc) 4 instead of Pd(OAc) 2 in the reaction with 2b did not yield the products 3b and 4b (Table 4); Cu(OAc) 2 forms a complex with the alkene, and thus it would not operate as oxidizing agent. Mn(OAc) 3 is not effective since it oxidizes AcOH [16].…”

Section: Effects Of Oxidantsmentioning

confidence: 99%

“…The use of Cu(OAc) 2 , Mn(OAc) 3 or Pb(OAc) 4 instead of Pd(OAc) 2 in the reaction with 2b did not yield the products 3b and 4b (Table 4); Cu(OAc) 2 forms a complex with the alkene, and thus it would not operate as oxidizing agent. Mn(OAc) 3 is not effective since it oxidizes AcOH [16]. Pb(OAc) 4 is too strong an oxidant to be effective, giving a lot of unidentified products.…”

Section: Effects Of Oxidantsmentioning

confidence: 99%

“…Since AgOAc is complexed with alkene, it would be not so effective for the reaction. 3 2.4 0 0 -Pb(OAc) 4 2.4 0 0 -a The yields are calculated to be 100% when two moles of product are formed from one mole Pd(OAc) 2 or Cu(OAc) 2 and from two moles AgOAc. b Pd(OAc) 2 (0.60 mmol) and Cu(OAc) 2 (3.6 mmol) were used, and the yields are obtained on the basis of Pd(OAc) 2 .…”

Section: Effects Of Oxidantsmentioning

confidence: 99%

“…Thus, the species with λ max 375 nm might be the disulfide radical cation, which would be independent of oxidative metals [7]. Considering that the intermediate using AlCl 3 can bring about an aromatic methylthiolation [7] whereas that using AgOAc is not subject to the aromatic methylthiolation but can react with alkene to form a thiiranium ion [9], we can regard the following: a very small amount of the disulfide radical cation and a more large amount of a sulfonium ion [MeS-S + (Me)Ag] − OAc (this has no visible absorption due to a σ S-Ag bond) are generated as the intermediates when AgOAc is dissolved in 1. Considering that one mole of product is formed from one mole of Pd(OAc) 2 , then we observe that the total yield of 3 and 4 is more than 100%.…”

Section: Mes-smementioning

confidence: 99%

“…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%

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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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Section: Effects Of Oxidantsmentioning

confidence: 99%

Section: Effects Of Oxidantsmentioning

confidence: 99%

Section: Effects Of Oxidantsmentioning

confidence: 99%

Section: Mes-smementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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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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A Novel Electrophilic Diamination Reaction of Alkenes

Li¹,

Wei²,

Kim³

et al. 2001

Angew. Chem.

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Electrophilic addition reactions of olefins have been of fundamental importance in organic chemistry [1] because these reactions can convert inexpensive petroleum alkenes into chemically and biologically useful compounds. At present, olefinic additions involving three or more components in a single operation are rare, [2,3] which is probably because of the fact that only a few electrophilic addition intermediates enable multistep transformations. [4, 5] Recently, we developed several new eletrophilic addition reactions, aminohalogenation, and a,b-differentiated diamination reactions by using Nhalogenosulfonamides as the electrophiles. [6,7] The regio-and stereochemical features of the resulting haloamine and diamine products have unambiguously proven the formation of N-(p-tosyl),N-haloaziridinium or N-(o-nosyl),N-haloaziridinium species during the reaction processes. In our continuing research on this topic we have now discovered a novel three-component reaction (Scheme 1) which provides access to imidazolines [8] and a,b-diamino derivatives. [9, 10] Scheme 1. Chalcone-based electrophilic diamination reaction.The current study was initiated by attempts to render the parent version of the aminohalogenation reaction asymmetric and catalytic. [6] Unfortunately, the success of this effort has been seriously limited thus far. For most of the cases we examined the reaction was either significantly deactivated or poor enantiomeric excesses resulted when chiral amine ligands were employed together with copper or zinc ions. Therefore, the search for other metal alternatives or metal ± ligand complexes became necessary. When rhodium compounds were examined [11] (for example, rhodium(ii) acetate dimer, rhodium(ii) trifluoroacetate dimer, and rhodium(ii) heptafluorobutyrate dimer) the reaction of methyl cinnamate with TsNCl 2 (Ts tosyl toluene-4-sulfonyl) led to the formation of complexes and a major side product. This side product was isolated in a yield varying between 18 ± 25 % when the above catalysts were employed, although the haloamine product was generated predominantly. The subsequent X-ray structural analysis revealed that this new side product is essentially a multifuctionalized imidazoline derivative ( Figure 1). Figure 1. X-ray structure of 1-p-toluenesulfonyl-2-dichloromethyl-4-phenyl-5-methyloxycarbonylimidazoline.[9] a)

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