15045-02-0Relevant articles and documents
Asymmetric Catalytic Epoxidation of Terminal Enones for the Synthesis of Triazole Antifungal Agents
Feng, Xiaoming,He, Qianwen,Liu, Xiaohua,Zhang, Dong,Zhang, Fengcai
, p. 6961 - 6966 (2021/09/11)
An enantioselective epoxidation of α-substituted vinyl ketones was realized to construct the key epoxide intermediates for the synthesis of various triazole antifungal agents. The reaction proceeded efficiently in high yields with good enantioselectivities by employing a chiral N,N′-dioxide/ScIII complex as the chiral catalyst and 35% aq. H2O2 as the oxidant. It enabled the facile transformation for optically active isavuconazole, efinaconazole, and other potential antifungal agents.
Br?nsted Base-Catalyzed Transformation of α,β-Epoxyketones Utilizing [1,2]-Phospha-Brook Rearrangement for the Synthesis of Allylic Alcohols Having a Tetrasubstituted Alkene Moiety
Kondoh, Azusa,Tasato, Naoko,Aoki, Takuma,Terada, Masahiro
supporting information, p. 5170 - 5175 (2020/07/04)
A stereoselective transformation of α,β-epoxyketones into alkenylphosphates having a hydroxymethyl group on the β-carbon was established by utilizing the [1,2]-phospha-Brook rearrangement under Br?nsted base catalysis. The reaction involves the catalytic generation of an α-oxygenated carbanion located at the α-position of an epoxide moiety through the [1,2]-phospha-Brook rearrangement and the following epoxide opening. Further transformation of the alkenylphosphates by the palladium-catalyzed cross-coupling reaction with Grignard reagents provided allylic alcohols having a stereodefined all-carbon tetrasubstituted alkene moiety.
Stereodivergent Access to Enantioenriched Epoxy Alcohols with Three Stereogenic Centers via Ruthenium-Catalyzed Transfer Hydrogenation
Zhao, Zhifei,Bagdi, Prasanta Ray,Yang, Shuang,Liu, Jinggong,Xu, Weici,Fang, Xinqiang
, p. 5491 - 5494 (2019/08/01)
The resolution technique of stereodivergent reaction on racemic mixtures (stereodivergent RRM) was employed for the first time in ruthenium complex catalyzed transfer hydrogenation of racemic epoxy ketones, providing a new and very simple method that allows access to enantioenriched epoxy alcohols with three stereogenic centers in a one-step fashion. The protocol features simple reaction conditions, practical operation, ability to scale up, and broad group tolerance.
One-pot synthesis of α,β-epoxy ketones by palladium-catalyzed epoxidation-oxidation of terminal allylic alcohols
Singh, Fateh V.,Pena, Jesus M.,Stefani, Hélio A.
experimental part, p. 1671 - 1673 (2010/05/19)
Described herein is a one-pot synthesis of α,β-epoxy ketones using a palladium-catalyzed epoxidation-oxidation sequence. Functionalized terminal allylic alcohols are treated with m-CPBA under mild reaction conditions to obtain the α,β-epoxy ketones. The m
Homologation of vicinal polyketone networks to epoxy ketones with diazomethane
Hartung, Ryan E.,Paquette, Leo A.
, p. 23 - 26 (2007/10/03)
Admixture of vicinal di-, tri-, and tetraketones with ethereal diazomethane results in one-time methylene transfer to the less hindered face of the sterically most accessible and electron-deficient carbonyl group to deliver epoxy ketones in a highly selec
Development of the Julia asymmetric epoxidation reaction. Part 2. Application of the oxidation to alkyl enones, enediones and unsaturated keto esters
Kroutil, Wolfgang,Lasterra-Sanchez, M. Elena,Maddrell, Samuel J.,Mayon, Patrick,Morgan, Phillip,Roberts, Stanley M.,Thornton, Steven R.,Todd, Christine J.,Tueter, Melek
, p. 2837 - 2844 (2007/10/03)
Polyleucine-based systems have been used to catalyse the asymmetric oxidation of a variety of alkyl enones 1-4, 9-14, an enynone 16 and a dienone 17 to afford the corresponding epoxides 5-8, 18-26 in good to excellent yield and optical purity. A range of enediones 30-32, 34 and one unsaturated keto ester 33 have also been epoxidised stereoselectively to afford optically active epoxides 35-39. The epoxidations were carried out with basic peroxide as the oxidant; the polyleucine catalyst was prepared from leucine N-carboxyanhydride using 1,3-diaminopropane, water (employing a humidity cabinet) or a polystyrene immobilised amine as the initiator. Preliminary mass spectral data on material derived from L-leucine and 1,3-diaminopropane (DAP-PLL) suggest that the catalyst consists of material that contains 22 ± 10 leucine residues.
Ttimethylsilyl Cyanide - A Reagent for Umpolung, XVIII. - Nucleophilic Acylation of α-Chlorocarbonyl Compounds - a Novel and Diastereoselective Approach to Substituted α,β-Epoxy Ketones
Huenig, Siegfried,Marschner, Claus
, p. 107 - 114 (2007/10/02)
The addition products of trimethylsilyl cyanide and benzaldehyde (1a), furfural (1b), and α,β-unsaturated aldehydes 2a-c, respectively, react after deprotonation with α-chloroaldehydes and -ketones 3a-d.By 1,4-O,O-silyl rearrangement and cyanide elimination O-trimethylsilyl acyloins 4 and 9, respectively, are formed.With fluoride, 4 and 9 react to α,β-epoxy ketones 5 and 10 in high yield and with E/Z selectivities from 80:20 to >95:5.By this novel route even α,β-unsaturated epoxy ketones (10) become available.
Diozonolyses of Acyclic Conjugated Dienes in Methanol
Griesbaum, Karl,Zwick, Gerhard
, p. 229 - 243 (2007/10/02)
In the diozonolyses of isoprene (1a), 2-methyl-3-phenyl-1,3-butadiene (1b), 2,3-diphenyl-1,3-butadiene (26), and 2,3,4,5-tetramethyl-2,4-hexadiene (30) in methanol subsequent reactions of the primary cleavage products afforded abnormal products, which arose from cleavage of both the double bonds and the single bonds of the diene systems.In addition, the diozonolyses of 26 and 30 gave products, in which one of the double bonds of the respective diene system has been epoxidized.The mode of formation of the abnormal cleavage products has been elucidated by the ozonolysis of the intermediate products, viz. of α,β-unsaturated methoxyhydroperoxides and of α,β-unsaturated carbonyl compounds.
Monoozonolyses of Acyclic Conjugated Dienes
Griesbaum, Karl,Zwick, Gerhard
, p. 3041 - 3057 (2007/10/02)
Monoozonolyses of isoprene (1a), 2-methyl-3-phenyl-1,3-butadiene (1b), 2,3-diphenyl-1,3-butadiene (25), and 2,3,4,5-tetramethyl-2,4-hexadiene (34) have been examined in pentane and in methanol.The dienes 1a, b and 25 afforded all possible α,β-unsaturated monoozonides and α,β-unsaturated methoxy hydroperoxides, respectively, whereas diene 34 gave no ozonide and no α,β-unsaturated methoxy hydroperoxide.From the dienens 25 and 34, the corresponding monoepoxides have been formed additionally.The results allow some conclusions concerning the regioselectivity of ozone attack at the unsymmetrically substituted dienes 1a, b as well as concerning the cleavage directions of primary ozonides.
