Phase-Transfer-Catalyzed Enantioselective α-Hydroxylation of Acyclic and Cyclic Ketones with Oxygen
摘要:
An efficient and enantioselective alpha-hydroxylation of acyclic as well as cyclic ketones using molecular oxygen has been developed. This simple catalytic procedure uses a readily available phase transfer catalyst and produces a wide range of valuable tertiary a-hydroxy ketones in good to excellent enantiopurity.
Flexible Stereoselective Functionalizations of Ketones through Umpolung with Hypervalent Iodine Reagents
作者:Pushpak Mizar、Thomas Wirth
DOI:10.1002/anie.201400405
日期:2014.6.2
The functionalization of carbonyl compounds in the α‐position has gathered much attention as a synthetic route because of the wide biological importance of such products. Through polarity reversal, or “umpolung”, we show here that typical nucleophiles, such as oxygen, nitrogen, and even carbon nucleophiles, can be used for addition reactions after tethering them to enol ethers. Our findings allow novel
New methods and reagents in organic synthesis. 75. asymmetric synthesis of α-hydroxy ketones using chiral phase transfer catalysts
作者:Moriyasu Masui、Akira Ando、Takayuki Shioiri
DOI:10.1016/0040-4039(88)85224-9
日期:——
Optically active α-hydroxyketones are obtained by oxidation of achiral ketones with molecular oxygen in two phase system usingchiralphasetransfercatalysts.
光学活性α-羟基酮是通过使用手性相转移催化剂在两相体系中用分子氧将非手性酮氧化而获得的。
Chemistry of oxaziridines. 14. Asymmetric oxidation of ketone enolates using enantiomerically pure (camphorylsulfonyl)oxaziridine
作者:Franklin A. Davis、Aurelia C. Sheppard、Bang Chi Chen、M. Serajul Haque
DOI:10.1021/ja00174a035
日期:1990.8
Le mecanisme met en jeu une substitution de type SN2 de l'anion enolate sur l'oxaziridine via un etat de transition «ouvert»
Le mecanisme 通过 un etat de transition «ouvert» 遇到 en jeu une 取代 SN2 型 de l'anion enolate sur l'oxaziridine
(Camphorylsulfonyl)imine dianion in the synthesis of new optically pure (camphorylsulfonyl)oxaziridine derivatives
作者:Franklin A. Davis、Michael C. Weismiller、G.Sankar Lal、Bang Chi Chen、Robert M. Przeslawski
DOI:10.1016/s0040-4039(00)99534-0
日期:1989.1
New, more efficient enantiomerically pure (camphorylsulfonyl)oxaziridines are prepared by mono alkylation of the dianion of (camphorsulfonyl)imine at the carbon atom adjacent to the sulfonyl group.
Synthesis and Reactions of <i>exo</i>-Camphorylsulfonyloxaziridine
作者:Franklin A. Davis、Rajarathnam E. Reddy、Parimala V. N. Kasu、Padma S. Portonovo、Patrick J. Carroll
DOI:10.1021/jo961991v
日期:1997.5.1
The first example of an exo-camphorylsulfonyloxaziridine 4a was prepared by m-CPBA oxidation of camphor imine 9. This surprising result is due to the conformation of the imine which apparently prevents attack of the peracid from the endo direction. Similar oxidations of all other camphorsulfonylimines result in the endo-oxaziridine exclusively. Asymmetric oxidation of sulfides to sulfoxides and the alpha-hydroxylation of enolates by 4 can be interpreted in terms of open transition states where nonbonded interactions are minimized. These results support earlier conclusions and predictions of the stereoselectivity and mechanisms of molecular recognition by the N-sulfonyloxaziridine class of oxidizing reagents.