- Preparation of O-Protected Cyanohydrins by Aerobic Oxidation of α-Substituted Malononitriles in the Presence of Diarylphosphine Oxides
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A mild, reagent-cyanide-free, and efficient synthesis of O-phosphinoyl-protected cyanohydrins from readily available α-substituted malononitriles was realized using diarylphosphine oxides in the presence of O2. Mechanistic studies indicated that in addition to the initial aerobic oxidation of the malononitrile derivative notable features of this process include the formation of a tetrahedral intermediate and a subsequent intramolecular rearrangement. The phosphinoyl-protecting group can be removed by alcoholysis or by reduction with DIBAL-H.
- Zhang, Dapeng,Lian, Mingming,Liu, Jia,Tang, Shukun,Liu, Guangzhi,Ma, Cunfei,Meng, Qingwei,Peng, Haisheng,Zhu, Daling
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- Stereoselective C?C Oxidative Coupling Reactions Photocatalyzed by Zwitterionic Ligand Capped CsPbBr3 Perovskite Quantum Dots
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Semiconductor quantum dots (QDs) have attracted tremendous attention in the field of photocatalysis, owing to their superior optoelectronic properties for photocatalytic reactions, including high absorption coefficients and long photogenerated carrier lifetimes. Herein, by choosing 2-(3,4-dimethoxyphenyl)-3-oxobutanenitrile as a model substrate, we demonstrate that the stereoselective (>99 %) C?C oxidative coupling reaction can be realized with a high product yield (99 %) using zwitterionic ligand capped CsPbBr3 perovskite QDs under visible light illumination. The reaction can be generalized to different starting materials with various substituents on the phenyl ring and varied functional moieties, producing stereoselective dl-isomers. A radical mediated reaction pathway has been proposed. Our study provides a new way of stereoselective C?C oxidative coupling via a photocatalytic means using specially designed perovskite QDs.
- Cai, Tong,Candler, Yolanda,Chen, Ou,He, Jie,Hills-Kimball, Katie,Shi, Wenwu,Wang, Ping,Wei, Zichao,Yang, Hanjun,Yuan, Yucheng,Zhu, Hua
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supporting information
p. 22563 - 22569
(2020/10/12)
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- Enantioselective Michael additions to α,β-unsaturated imides catalyzed by a salen-al complex
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(Salen)aluminum complex 1b is an efficient catalyst for the conjugate addition of di- and trisubstituted nitriles to a wide range of acyclic alkyl- and aryl-substituted α,β-unsaturated imides. This new methodology provides access to multifunctional compounds that previously have not been readily accessible in enantioenriched form. Synthetic applications of these products include the preparation of enantiomerically enriched piperidines, as exemplified by an expedient asymmetric catalytic synthesis of (-)-paroxetine. Copyright
- Taylor, Mark S.,Jacobsen, Eric N.
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p. 11204 - 11205
(2007/10/03)
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