25966-61-4Relevant articles and documents
Rapid transformation of sulfinate salts into sulfonates promoted by a hypervalent iodine(III) reagent
Deruer, Elsa,Hamel, Vincent,Blais, Samuel,Canesi, Sylvain
supporting information, p. 1203 - 1207 (2018/06/04)
An alternative method for forming sulfonates through hypervalent iodine(III) reagent-mediated oxidation of sodium sulfinates has been developed. This transformation involves trapping reactive sulfonium species using alcohols. With additional optimization of the reaction conditions, the method appears extendable to other nucleophiles such as electron-rich aromatic systems or cyclic ethers through a ring opening pathway.
Kinetic resolution of chiral α-olefins using optically active ansa-zirconocene polymerization catalysts
Baar, Cliff R.,Levy, Christopher J.,Min, Endy Y.-J.,Henling, Lawrence M.,Day, Michael W.,Bercaw, John E.
, p. 8216 - 8231 (2007/10/03)
A series of enantiopure C1-symmetric metallocenes, {(SiMe 2)2[η5-C5H(CHMe 2)2][η5-C5H2((S) CHMeCMe3)]}ZrCl2, (S)-2, {(SiMe2) 2[η5-C5H(CHEt2) 2][η5-C5H2((S)-CHMeCMe 3)]}ZrCl2, (S)-6, and {(SiMe2) 2[η5-C5HCy2][η5- C5H2((S)-CHMeCMe3)]}ZrCl2), (S)-7 (Cy = cyclohexyl), zirconocene dichlorides that have an enantiopure methylneopentyl substituent on the "upper" cyclopentadienyl ligand, and diastereomerically pure precatalysts, {(SiMe2) 2[η5-C5H((S)-CHMeCy)(CHMe 2)][η5-C5H3]}ZrCl2, (S)-8a and (S)-8b, which have an enantiopure, 1-cyclohexylethyl substituent on the "lower" cyclopentadienyl ligand, has been synthesized for use in the polymerization of chiral α-olefins. When activated with methylaluminoxane, these metallocenes show unprecedented activity for the polymerization of bulky racemic monomers bearing substitution at the 3- and/or 4-positions. Due to the optically pure nature of these single site catalysts, they effect kinetic resolution of racemic monomers: the polymeric product is enriched with the faster reacting enantiomer, while recovered monomer is enriched with the slower reacting enantiomer. The two components are easily separated. For most olefins surveyed, a partial kinetic resolution was achieved (s = kfaster/kslower ≈ 2), but, in one case, the polymerization of 3,4-dimethyl-1-pentene, high levels of separation were obtained (s > 15). 13C NMR spectroscopy of poly (3-methyl-1-pentene) produced with (S)-2 indicates that the polymers are highly isotactic materials. X-ray crystal structure determinations for (S)-2, {(SiMe2)2[η 5-C5H(CHMe2)2][η5- C5H2((S)-CHMeCMe3)]}Zr(SC6H 5)2, (S)-6, and (S)-7 have been used in combination with molecular mechanics calculations to examine the prevailing steric interactions expected in the diastereomeric transition states for propagation during polymerization. Precatalysts (S)-8a and (S)-8b are less selective polymerization catalysts for the kinetic resolution of 3-methyl-1-pentene than are (S)-2, (S)-6, and (S)-7.
Facile and practical methods for the sulfonylation of alcohols using Ts(Ms)Ci and Me2N(CH2)(n)NMe2 as a key base
Yoshida, Yoshihiro,Shimonishi, Koji,Sakakura, Yoshiko,Okada, Shin,Aso, Naoya,Tanabe, Yoo
, p. 1633 - 1636 (2007/10/03)
Several alcohols were smoothly and practically tosylated by two Methods A and B. Method A uses the TsCl/Me2N(CH2)(n)NMe2 (n = 3 or 6) reagent and Method B uses TsCl/Et3N/catalytic Me2N(CH2)
