Highly Enantioselective Oxidation of Sulfides to Sulfoxides by a New Oxaziridinium Salt
作者:R. E. del Río、B. Wang、S. Achab、L. Bohé
DOI:10.1021/ol0702573
日期:2007.6.1
The new oxaziridinium salt 5 (R2 = TBDPS) is an effective reagent for the highly enantioselective oxidation of sulfides to sulfoxides with up to >99% ee and good yields. As such, it represents a new valuable nonmetallic alternative to the existing methods for asymmetric sulfoxidation.
Development and application of versatile bis-hydroxamic acids for catalytic asymmetric oxidation
作者:Allan U. Barlan、Wei Zhang、Hisashi Yamamoto
DOI:10.1016/j.tet.2007.03.071
日期:2007.7
preliminary results of our new designed C(2)-symmetric bis-hydroxamic acid (BHA) ligands and the application of the new ligands for vanadium-catalyzed asymmetric epoxidation of allylic alcohols as well as homoallylic alcohols. From this success we demonstrate the versatile nature of BHA in the molybdenum catalyzed asymmetric oxidation of unfunctionalized olefins and sulfides.
Iron-Catalyzed Imidative Kinetic Resolution of Racemic Sulfoxides
作者:Jun Wang、Marcus Frings、Carsten Bolm
DOI:10.1002/chem.201303850
日期:2014.1.20
resolution of racemic sulfoxides requires either custom substrates or shows moderate enantioselectivity, leading to achiral coproducts (such as sulfones) as an intrinsic part of the process. A new strategy is demonstrated that allows the resolution of racemic sulfoxides through catalytic asymmetric nitrene‐transfer reactions. This approach gives rise to both optically active sulfoxides and highly enantioenriched
Chiral Ionic Liquids as Stationary Phases in Gas Chromatography
作者:Jie Ding、Thomas Welton、Daniel W. Armstrong
DOI:10.1021/ac049144c
日期:2004.11.1
Recently, it has been found that room-temperature ionic liquids can be used as stable, unusual selectivity stationary phases. They show “dual nature” properties, in that they separate nonpolar compounds as if they are nonpolar stationary phases and separate polar compounds as if they are polar stationary phases. Extending ionic liquids to the realm of chiral separations can be done in two ways: (1) a chiral selector can be dissolved in an achiral ionic liquid, or (2) the ionic liquid itself can be chiral. There is a single precedent for the first approach, but nothing has been reported for the second approach. In this work, we present the first enantiomeric separations using chiral ionic liquid stationary phases in gas chromatography. Compounds that have been separated using these ionic liquid chiral selectors include alcohols, diols, sulfoxides, epoxides, and acetylated amines. Because of the synthetic nature of these chiral selectors, the configuration of the stereogenic center can be controlled and altered for mechanistic studies and reversing enantiomeric retention.
Novel Catalytic Asymmetric Sulfoxidation in Water Using the Hypervalent Iodine Reagent Iodoxybenzene.
作者:Hirofumi TOHMA、Shinobu TAKIZAWA、Hironori MORIOKA、Tomohiro MAEGAWA、Yasuyuki KITA
DOI:10.1248/cpb.48.445
日期:——
A new catalyticasymmetric oxidation of sulfides to sulfoxides in water using the hypervalentiodine(V) reagent iodoxybenzene (PhIO2) has been developed. This methodology is distinctly different from the previously reported use of cyclodextrins or biological catalysts and provides a new route to asymmetric sulfoxidation in water.