41578-04-5Relevant articles and documents
Novel behavior of thiiranium radical cation intermediates. Reactions of dimethyl disulfide with alkenes in the presence of Pd(OAc)2
Takeuchi, Hiroshi,Takatori, Junnichi,Iizuka, Shingo
, p. 916 - 926 (2000)
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 ace-toxymethylthiolation 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 MeNO2) 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 MeNO2 not containing AcOH. A solution of Pd(OAc)2 in 1 exhibits λmax 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 SN2 ring-opening 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.
Chiral amide directed assembly of a diastereo- and enantiopure supramolecular host and its application to enantioselective catalysis of neutral substrates
Zhao, Chen,Sun, Qing-Fu,Hart-Cooper, William M.,Dipasquale, Antonio G.,Toste, F. Dean,Bergman, Robert G.,Raymond, Kenneth N.
supporting information, p. 18802 - 18805 (2014/01/06)
The synthesis of a novel supramolecular tetrahedral assembly of K 12Ga4L6 stoichiometry is reported. The newly designed chiral ligand exhibits high diastereoselective control during cluster formation, leading exclusively t
Studies on the Stereoselectivity of Hydride Reductions on 2-(Methylthio)- and 2-(Methylsulfonyl)cyclohexanones
Carreno, M. Carmen,Dominguez, Enrique,Garcia-Ruano, Jose L.,Rubio, Almudena
, p. 3619 - 3625 (2007/10/02)
The results obtained in the reductions of 2-X-cyclohexanones and cis- and trans-4-tert-butyl-2-X-cyclohexanones (X=SMe, SO2Me) with different hydrides are reported.When the sulfur functions adopt the axial disposition, the cyclohexanol resulting from the
