- Iridium Complexes as Efficient Catalysts for Construction of α-Substituted Ketones via Hydrogen Borrowing of Alcohols in Water
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Ketones are of great importance in synthesis, biology, and pharmaceuticals. This paper reports an iridium complexes-catalyzed cross-coupling of alcohols via hydrogen borrowing, affording a series of α-alkylated ketones in high yield (86 %–95 %) and chemoselectivities (>99 : 1). This methodology has the advantages of low catalyst loading (0.1 mol%) and environmentally benign water as the solvent. Studies have shown the amount of base has a great impact on chemoselectivities. Meanwhile, deuteration experiments show water plays an important role in accelerating the reduction of the unsaturated ketones intermediates. Remarkably, a gram-scale experiment demonstrates this methodology of iridium-catalyzed cross-coupling of alcohols has potential application in the practical synthesis of α-alkylated ketones.
- Luo, Nianhua,Zhong, Yuhong,Wen, Huiling,Shui, Hongling,Luo, Renshi
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p. 1355 - 1364
(2021/03/03)
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- DMF Dimethyl Acetal as Carbon Source for α-Methylation of Ketones: A Hydrogenation-Hydrogenolysis Strategy of Enaminones
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A novel heterogeneous catalytic hydrogenation-hydrogenolysis strategy has been developed for the α-methylation of ketones via enaminones using DMF dimethyl acetal as carbon source. This strategy provides a very convenient route to α-methylated ketones using a variety of ketones without any base or oxidant. (Chemical Equation Presented).
- Borah, Ashwini,Goswami, Limi,Neog, Kashmiri,Gogoi, Pranjal
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p. 4722 - 4728
(2015/05/13)
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- Total chiral synthesis of azole antifungals via α-hydroxylation of ketones
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The use of camphorsulfonyl oxaziridines for the preparation of 2',4'-difluoro-(R)-2-hydroxypropiophenone, (2), a key intermediate for the synthesis of azole antifungals Sch 42427 and ER-30346 (1) in excellent enantiomeric excess and high chemical yield is described.
- Gala, Dinesh,DiBenedetto, Donald J.,Mergelsberg, Ingrid,Kugelman, Max
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p. 8117 - 8120
(2007/10/03)
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- Preparation of chiral hydroxyketones
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A process for preparing an hydroxyketone of the formula (X): STR1 wherein Ar represents substituted phenyl, aromatic heterocyclic, or substituted aromatic heterocyclic; R1 and R2 independently represents hydrogen, C-1 to C-16 alkyl, aromatic, substituted aromatic, aromatic heterocyclic, substituted aromatic heterocyclic or C-1 to C-5 alkyl covalently bonded to Ar, with the provision that R1 and R2 are different. The process comprises contacting a compound of the formula (V): STR2 with a solvent, a base and a chiral hydroxylating agent at a temperature of about -85° C. or less. Compounds of the formulae STR3 also are disclosed.
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