Nuclear Magnetic Resonance Studies of Sulfur Compounds. II. The Substituent Effect on Geminal Coupling Constants and on Magnetic Nonequivalence of the Methylene Protons of Sulfoxides.
作者:Motohiro Nishio
DOI:10.1248/cpb.15.1669
日期:——
Nuclear magnetic resonance spectra were obtained for a number of sulfoxides, whose methylene protons are magnetically nonequivalent. The coupling constants between these protons depend on the electronic properties of the substituent adjacent to the coupling protons. The substituent effect on magnetic nonequivalence was also studied and it is demonstrated that the electronic properties of the substituent constitute an important factor responsible for the magnitude of magnetic nonequivalence.
A switchable and benign protocol for chemoselectivesynthesis of sulfoxides and α-alkoxy-β-ketothioethers has been developed. It was determined that various thiophenols and alkenes/alkynes are compatible to realize the target compounds from a medium to a high yield by regulating the reaction temperature. In particular, methanol not only served as a solvent but also participated in the reaction process
Solvent-Enabled Radical Selectivities: Controlled Syntheses of Sulfoxides and Sulfides
作者:Huamin Wang、Qingquan Lu、Chaohang Qian、Chao Liu、Wei Liu、Kai Chen、Aiwen Lei
DOI:10.1002/anie.201508729
日期:2016.1.18
Controllingselectivity is of central importance to radical chemistry. However, the highly reactive and unstable radical intermediates make this task especially challenging. Herein, a strategy for taming radical redox reactions has been developed, in which solvent‐bonding can alter the reactivity of the generated radical intermediates and thereby drastically alter the reaction selectivity at room temperature
Stannous triflate promotes rearrangement of β-keto sulfoxides to generate α-thiocarbocation, which in turn react with silyl enol ethers to give 2-arylsulfenyl-1,4-diketones in good yields.
Novel 1,2,4-benzothiadiazines substituted with an amino, alkylamino, or dialkylamino group in the 3-position are useful as central nervous system depressants and as diuretics.