40327-65-9Relevant academic research and scientific papers
Asymmetric Epoxidation of Enones Promoted by Dinuclear Magnesium Catalyst
Jaszczewska-Adamczak, Joanna A.,Mlynarski, Jacek
supporting information, p. 4247 - 4255 (2021/07/17)
Asymmetric synthesis with cheaper and non-toxic alkaline earth metal catalysts is becoming an important and sustainable alternative to conventional catalytic methodologies mostly relying on precious metals. In spite of some sustainable methods for enantioselective epoxidation of enones, the development of a well-defined and efficient catalyst based on magnesium complexes for these reactions is still a challenging task. In this perspective, we present the application of chiral dinuclear magnesium complexes for asymmetric epoxidation of a broad range of electron-deficient enones. We demonstrate that the in situ generated magnesium-ProPhenol complex affords enantioenriched oxiranes in high yields and with excellent enantioselectivities (up to 99% ee). Our extensive study verifies the literature data in this area and provides a step forward to better understand the factors controlling the oxygenation process. Elaborated catalyst offers mild reaction conditions and a truly wide substrate scope. (Figure presented.).
Highly Enantioselective Epoxidation of α,β-Unsaturated Ketones Using Amide-Based Cinchona Alkaloids as Hybrid Phase-Transfer Catalysts
Jurczak, Janusz,Majdecki, Maciej,Tyszka-Gumkowska, Agata
supporting information, (2020/11/13)
A series of 20 one chiral epoxides were obtained with excellent yields (up to 99%) and enantioselectivities (up to >99% ee) using hybrid amide-based Cinchona alkaloids. Our method is characterized by low catalyst loading (0.5 mol %) and short reaction times. Moreover, the epoxidation process can be carried out in 10 cycles, without further catalyst addition to the reaction mixture. This methodology significantly enhance the scale of the process using very low catalyst loading.
Organocatalytic Enantioselective γ-Elimination: Applications in the Preparation of Chiral Peroxides and Epoxides
Chen, Zhili,Gong, Xiangnan,Hu, Fangli,Huang, Shengli,Jia, Shiqi,Qin, Wenling,Tan, Yu,Xu, Da,Yan, Hailong
, p. 1934 - 1940 (2020/03/24)
An organocatalyzed enantioselective γ-elimination process has been achieved and applied in the kinetic resolution of peroxides to access chiral peroxides and epoxides. The reaction provided a pathway for the preparation of two useful synthetic and biologically important structural motifs through a single-step reaction. A range of substrates has been resolved with a selectivity factor up to 63. The obtained enantioenriched peroxides and epoxides allowed a series of transformations with retained optical purities.
Iron-catalyzed carbonylation-peroxidation of alkenes with aldehydes and hydroperoxides
Liu, Weiping,Li, Yuanming,Liu, Kaisheng,Li, Zhiping
supporting information; experimental part, p. 10756 - 10759 (2011/08/22)
A three-component reaction of alkenes, aldehydes, and hydroperoxides catalyzed by FeCl2 to β-peroxy ketones has been achieved. This three-component reaction can be also applied to the synthesis of α-carbonyl epoxides, through either a stepwise base-induced epoxidation of the separated β-peroxy ketone products or a one-pot process by simply adding base to the reaction mixture after the completion of the three-component reaction.
Development of the Julia asymmetric epoxidation reaction. Part 1. Application of the oxidation to enones other than chalcones
Lasterra-Sanchez, M. Elena,Felfer, Ulfried,Mayon, Patrick,Roberts, Stanley M.,Thornton, Steven R.,Todd, Christine J.
, p. 343 - 348 (2007/10/03)
Asymmetric epoxidation of a variety of enones 3, 6, 8, 10, 12, 14, 16, 18, 21, 22, 26, 28-30 and 36 gives the corresponding oxiranes in good to excellent yield and optical purity. The oxidation medium consists of basic peroxide or sodium perborate or sodi
A stereocontrolled approach to electrophilic epoxides
Meth-Cohn, Otto,Moore, Clive,Taljaard, Heinrich C.
, p. 2663 - 2674 (2007/10/02)
Lithium t-butyl hydroperoxide (easily generated by addition of an alkyl-lithium to anhydrous t-butyl hydroperoxide in THF solution) is a powerful reagent for the epoxidation of electrophilic alkenes at -20 to 0 °C under full stereocontrol. Thus αβ-unsaturated esters, sulphones, sulphoximines, and amides are readily epoxidised with complete regio- and stereo-specificity and with considerable chiroselectivity (20-100%) when appropriate chiral auxiliaries such as menthyl, 8-phenylmenthyl, or a camphor-sulphonamide derivative are used. Asymmetric αβ-unsaturated sulphoximines undergo epoxidation with 100% diastereoselectivity. The only exceptions to stereocontrol noted are heavily substituted maleate esters such as di-t-butyl maleate. The αβ-epoxy amides are shown to be valuable sources of the corresponding epoxy ketones by treatment with an organolithium, allowing a stereo- and chemoselective entry in high yield to these useful intermediates.
