Enantioselective Vanadium-Catalyzed Oxidation of 1,3-Dithianes from Aldehydes and Ketones using β-Amino Alcohol Derived Schiff Base Ligands
作者:Yinuo Wu、Fei Mao、Fanchao Meng、Xingshu Li
DOI:10.1002/adsc.201000803
日期:2011.7
and ketones by β‐amino alcohol‐derived Schiffbase ligands with two stereogenic centers was investigated. Usingaqueoushydrogenperoxide as the oxidant and the Schiffbase 3b as a chiral ligand, a variety of 1,3‐dithianes derived from aldehydes were easily converted into the corresponding mono‐sulfoxides in good yields (81–88%) with excellent enantioselectivities (up to 99% ee). Additionally, 99% ee
Asymmetric Oxidation of Dithioacetals and Dithioketals Catalyzed by a Chiral Vanadium Complex
作者:Carsten Bolm、Frank Bienewald
DOI:10.1055/s-1998-1948
日期:1998.12
Vanadium-catalyzed enantioselective oxidations of dithioacetals and dithioketals with 30% aqueous H2O2 give the corresponding monosulfoxides with enantioselectivities of up to 85% ee. The scope of this asymmetric analysis has been investigated.
2,3-Dihydro-dithiin and -dithiepine-1,1,4,4-tetroxides: small molecule non-peptide antagonists of the human galanin hGAL-1 receptor
作者:Malcolm K Scott、Tina M Ross、Daniel H.S Lee、Hoau-Yan Wang、Richard P Shank、Kenneth D Wild、Coralie B Davis、Jeffrey J Crooke、Alexander C Potocki、Allen B Reitz
DOI:10.1016/s0968-0896(00)00062-6
日期:2000.6
The neuropeptide galanin modulates several physiological functions such as cognition, learning, feeding behavior, and depression, probably via the galanin 1 receptor(GAL-R1). Using an HTS assay based on I-125-human galanin binding to the human galanin-l receptor (hGAL-R1), we discovered a series of 1,4-dithiin and dithiipine-1,1,4,4-tetroxides that exhibited binding affinity IC50's to hGAL-R1 ranging from 190 to 2700 nM. Two of the dithiepin analogues, 7 and 23, behaved pharmacologically as hGAL-R1 antagonists in secondary assays involving adenylate cyclase activity and GTP binding to G-proteins. Analogues 7 and 23 were also active in functional assays involving galanin, reversing the inhibitory effect of galanin on acetylcholine (ACh) release in rat brain hippocampal slices and electrically-stimulated guinea pig ileum twitch. (C) 2000 Elsevier Science Ltd. All rights reserved.
Intramolecularly Sulfur-Stabilized Silicon Cations as Lewis Acid Catalysts
作者:Volker H. G. Rohde、Phillip Pommerening、Hendrik F. T. Klare、Martin Oestreich
DOI:10.1021/om500570d
日期:2014.7.14
The synthesis and spectroscopic characterization of previously unprecedented sulfur-stabilized silicon cations are reported. Several 1,3-dithiolan-2-yl- and 1,3-dithian-2-yl-substituted silanes were prepared and successfully transformed into the corresponding silicon cations by hydride abstraction. The silicon-sulfur interaction creates three consecutive stereocenters at three different elements. It is remarkable that the present stereocenter at the silicon atom determines the stereochemical outcome at the formerly prochiral sulfur and carbon atoms with excellent diastereoselectivity. All sulfur-stabilized silicon cations are shown to be potent catalysts in a challenging Diels-Alder reaction. Moreover, structurally related oxazoline-stabilized silicon cations were generated and characterized but found to be unreactive.