- Chemistry of the S=O Bond. 11- Carbon-13 and Oxygen-17 Nuclear Magnetic Resonance Studies of Stereoisomerism in 1,3,2-Dioxathiepanes
-
The stereoisomerism of some methyl-substituted 1,3,2-dioxathiepanes has been investigated by 13C and 17O NMR spectroscopy.The effects of substituents on the conformational equilibria of the seven-membered rings are discussed and compared with those for six-membered ring sulphites.KEY WORDS - 13C NMR 17O NMR Stereoisomerism 1,3,2-Dioxathiepanes
- Hellier, Desmond G.,Liddy, H. Glendon
-
-
Read Online
- Probing the importance of the hemilabile site of bis(phosphine) monoxide ligands in the copper-catalyzed addition of diethylzinc to N-phosphinoylimines: Discovery of new effective chiral ligands
-
(Chemical Equation Presented) The hemilabile ligand Me-DuPHOS(O) 2 has proven to be a successful ligand for the copper-catalyzed addition of diethylzinc to N-phosphinoylimines. The corresponding α-chiral amines were obtained in high yields (80-98%) and enantiomeric ratios (19.0:1 to 99.0:1 er). Furthermore, this Cu?2 catalytic system has been shown to be effective in the addition of diethylzinc to nitroalkenes and in the reduction of β,β-disubstituted vinyl phenyl sulfones. This paper describes a general structure/selectivity study in which the three ligand subunits (chiral phospholane-linker-labile coordinating group (Z)) are systematically modified and tested in the copper-catalyzed addition of diethylzinc to the N-phosphinoylimine 1 derived from benzaldehyde. This study led to the discovery of a new class of effective chiral ligands that combine a chiral phospholane unit and an achiral phosphine oxide.
- Bonnaventure, Isabelle,Charette, Andre B.
-
p. 6330 - 6340
(2008/12/22)
-
- Preparation of cyclic sulfites by transesterification of diols and diisopropyl sulfite
-
Cyclic sulfites of 1,2-, 1,3- and 1,4-diols can be prepared in high yield by acid or base catalyzed transesterification with diisopropyl sulfite.
- King, Steven A.,Pipik, Brenda,Conlon, David A.,Bhupathy
-
p. 701 - 707
(2007/10/03)
-
- REACTION OF HYDROXY AND CARBONYL COMPOUNDS WITH SULFUR TETRAFLUORIDE IX. REACTIONS OF GLYCOLS WITH SULFUR TETRAFLUORIDE
-
Selective substitution of one of the hydroxyl groups by a fluorine atom occurs in the reactions of 1,2-, 1,3-, and 1,4-glycols with sulfur tetrafluoride under mild conditions.The regioselectivity of substitution in the case of unsymmetrical glycols depends on the electronic nature of the groups present in the molecules of the initial compounds.
- Hassanein, Salah Mohamed,Burmakov, A. I.,Bloshchitsa, F. A.,Yagupol'skii, L. M.
-
p. 1473 - 1477
(2007/10/02)
-
- ELECTROCHEMICAL REDUCTION OF CYCLIC AND ACYCLIC SULFATES.
-
It was confirmed that cyclic and acyclic sulfates of diols and monoalcohols could be reduced at cathodes in nonaqueous solvents. The reduction products were greatly affected by the molecular structures of the sulfates. The reduction of the cyclic sulfates of 1,2-diols yielded the corresponding alkenes and disulfate dianions of the parent diols in high yields and current efficiencies were based on one-electron reduction. On the other hand, the cyclic sulfates of 1,3- and 1,4-diols were also reduced by one-electron transfer under similar conditions, but the cycloalkanes expected were not formed and the products were cyclic ethers along with acyclic alkane or unsaturated alcohol. The reduction of the cyclic sulfate of hydrated formaldehyde, which is regarded as a 1,1-diol, did not give any identified products except for a small amount of methane.
- Nonaka,Kihara,Fuchigami,Baizer
-
p. 3160 - 3166
(2007/10/02)
-