- Chiral Primary Amine Catalyzed Enantioselective Tandem Reactions Based on Heyns Rearrangement: Synthesis of α-Tertiary Amino Ketones
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Herein, we disclose a new catalytic asymmetric tandem reaction based on the Heyns rearrangement for the synthesis of chiral α-amino ketones with readily available substrates. The rearrangement is different from the Heyns rearrangement in that the α-amino ketones were obtained without the shift of the carbonyl group. The key to success is using chiral primary amine as a catalyst by mimicking glucosamine-6-phosphate synthase in catalyzing the efficient Heyns rearrangement in organisms.
- Chen, Yue,Cui, Xin,Li, Guang-Xun,Nie, Xiao-Kang,Tang, Zhuo,Zhang, Shi-Qi
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p. 2069 - 2074
(2022/03/31)
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- Green preparation method α - hydroxyketone
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The invention relates to a green preparation method of alpha-hydroxyketone. The method comprises the following steps: adding ketone, iodine, 1,4-diazabicyclo[2.2.2]octane and methanol into a glass reaction bottle in sequence; then stirring and reacting for 14 to 30h at room temperature in an air atmosphere under the irradiation of a 23W compact type fluorescent lamp, so as to obtain a reaction mixture; carrying out silica gel column chromatographic separation to obtain the pure alpha-hydroxyketone. The green preparation method provided by the invention has the characteristics of greenness, high efficiency, simplicity in operation, moderate conditions, wide applicability and easiness for industrialization.
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Paragraph 0027-0030
(2020/08/27)
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- Α - hydroxy ketone compound low priced high-efficient synthetic method
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The invention discloses a cheap and efficient synthesis method of an alpha-hydroxyketone compound. The synthesis method is characterized in that a carbonyl compound undergoes an oxidation hydroxylation reaction at 10-120DEG C under normal pressure with iodine simple substance, N-bromosuccimide, copper bromide, bromine simple substance, hydrogen bromide, N-iodosuccimide or hydrogen iodide as a catalyst, sulfoxide as an oxidant, water or sulfoxide as a hydroxy source and sulfoxide, ethyl acetate, N,N-dimethyl formamide, acetonitrile, toluene, 1,4-dioxane, 1,2-dichloroethane, tetrahydrofuran or H2O as a solvent, and converts into the alpha-hydroxyketone compound in a high selectivity manner. Compared with traditional synthesis methods, the method disclosed in the invention has the advantages of simple operation, high yield, simple conditions, easy purification, small waste discharge amount, simple reaction apparatus, and easy industrial production. The method has wide applicability and can be used for synthesizing various alpha-hydroxyketone compounds.
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Paragraph 0080-0083
(2017/08/25)
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- N,N-Dimethylformamide (DMF) as a Source of Oxygen to Access α-Hydroxy Arones via the α-Hydroxylation of Arones
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An unprecedented α-hydroxylation strategy was developed for the synthesis of α-hydroxy arones using N,N-dimethylformamide (DMF) as an oxygen source. Control experiments demonstrated that the oxygen atom of the hydroxy group in the α-hydroxy arones produced in this reaction was derived from DMF. This new reaction therefore not only provides an alternative strategy for the α-hydroxylation of arones but also highlights the possibility of using the inexpensive common solvent DMF as a source of oxygen in organic synthesis.
- Liu, Weibing,Chen, Cui,Zhou, Peng
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p. 2219 - 2222
(2017/02/26)
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- I2- or NBS-catalyzed highly efficient α-hydroxylation of ketones with dimethyl sulfoxide
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An efficient method for the direct preparation of high synthetic valuable α-hydroxycarbonyls is described. The simple and readily available I2 or NBS was used as catalyst. DMSO acts as the oxidant, oxygen source, and solvent. A diverse range of tertiary Csp3-H bonds as well as more challenging secondary Csp3-H bonds could be hydroxylated in this transformation. The reaction is mild, less toxic and easy to perform.
- Liang, Yu-Feng,Wu, Kai,Song, Song,Li, Xinyao,Huang, Xiaoqiang,Jiao, Ning
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supporting information
p. 876 - 879
(2015/04/14)
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- Switching regioselectivity in crossed acyloin condensations between aromatic aldehydes and acetaldehyde by altering n -heterocyclic carbene catalysts
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An unprecedented high level of regioselectivities (up to 96%) in the intermolecular crossed acyloin condensations of various aromatic aldehydes with acetaldehyde was realized by an appropriate choice of N-heterocyclic carbene catalysts.(Figure Presented)
- Jin, Ming Yu,Kim, Sun Min,Han, Hogyu,Ryu, Do Hyun,Yang, Jung Woon
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supporting information; experimental part
p. 880 - 883
(2011/05/02)
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- Asymmetric oxidation of enol phosphates to α-hydroxy ketones by?(salen)manganese(III) complex. Effects of the substitution pattern of enol phosphates on the stereochemistry of oxygen?transfer
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This paper presents a study of enantioselective catalytic oxidation of a variety of differently substituted, cyclic (E) and acyclic (Z)-enol phosphates. The asymmetric oxidation of acyclic (Z)-enol phosphates containing alkoxy substituents in the phosphate group 2a, c, e-g, i, and j and Z-configured enol phosphates containing aryloxy substituents in the phosphate group 2b, d, and h afforded optically active α-hydroxy ketones 4a-j of opposite configuration with good to high enantioselectivity. The influence of electronic and steric effects of the enol phosphate substituents on the stereoselectivity of oxidation was studied.
- Koprowski, Marek,?uczak, Jerzy,Krawczyk, Ewa
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p. 12363 - 12374
(2007/10/03)
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- α-Hydroxy ketones in high enantiomeric purity from asymmetric oxidation of enol phosphates with (salen) manganese(III) complex
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Optically active α-hydroxy ketones 4 have been prepared in high enantioselectivity by the catalytic, enantioselective oxidation of easily available and stable (E)-enol phosphates 2 by (salen) Mn(III) complex.
- Krawczyk, Ewa,Koprowski, Marek,Skowronska, Aleksandra,Luczak, Jerzy
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p. 2599 - 2602
(2007/10/03)
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- Synthesis of α-acetoxy and formyloxy ketones by thallium(III) promoted α-oxidation
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Treatment of ketones with thallium(III) triflate in amide solvents at 60°C for 30 min followed by addition of small amounts of H2O cleanly provided the corresponding α-acyloxy ketones.
- Lee,Jin,Choi
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p. 956 - 957
(2007/10/03)
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- Enantioselective synthesis of (S)-2-hydroxypropanone derivatives by benzoylformate decarboxylase catalyzed C-C bond formation
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Chiral 2-hydroxypropanone derivatives 5a-v, 8a-d, and 10a, b were formed by benzoylformate decarboxylase (BFD) catalyzed C-C bond formation. A donor aldehyde and acetaldehyde as an acceptor were carboligated in aqueous buffer solution with remarkable ease in high chemical yield and good to high optical purity. The substrate range of this thiamin diphosphate dependent enzyme was examined to employ this benzoin condensation type reaction in stereoselective synthesis. The observed dependence of the enantiomeric excess on the substitution pattern could be exploited to design substrates resulting in high selectivity. Best substrates with regard to optical purity were meta- substituted benzaldehyde derivatives. To enable a general and convenient applicability of the BFD-catalyzed C-C bond formation, analytical batch experiments were scaled up to give (S)-2-hydroxy ketones in good to high yields on a preparative scale. Further, the solubility of some of the organic substrates in aqueous solution was increased by the use of cyclodextrin or buffer/DMSO mixtures.
- Duennwald, Thomas,Demir, Ayhan S.,Siegert, Petra,Pohl, Martina,Mueller, Michael
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p. 2161 - 2170
(2007/10/03)
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- Synthesis of aromatic aldehydes by laccase-mediator assisted oxidation
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Aromatic aldehydes can be prepared in aqueous medium by oxidation of the corresponding methyl aromatic compounds in the presence of oxygen, the enzyme laccase and catalytic amounts of various N-hydroxy compounds. Allylic alcohols also gave the corresponding aldehydes in good yield. Competing reactions reveal that the N-hydroxy compound is involved in the rate determining step of the reaction.
- Fritz-Langhals, Elke,Kunath, Brigitte
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p. 5955 - 5956
(2007/10/03)
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- Investigation of (oxodioxolenyl)methyl carbamates as nonchiral bioreversible prodrug moieties for chiral amines
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The preparation of(oxodioxolenyl)methyl carbamates and their evaluation as novel nonchiral prodrug moieties for chiral primary and secondary amino functional drugs are described. 4-(Carbamoylmethyl)-2-oxo-1,3-dioxolene derivatives of 3,4-dimethoxyphenethy
- Alexander, Jose,Bindra, Dilbir S.,Glass, Joan D.,Holahan, Marie A.,Renyer, Mara L.,Rork, Gerald S.,Sitko, Gary R.,Stranieri, Maria T.,Stupienski, Raymond F.,Veerapanane, Hemalata,Cook, Jacquelynn J.
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p. 480 - 486
(2007/10/03)
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- Fine regioselective tuning in the oxidation of sec,sec 1,2-diols by dimethyldioxirane
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Non-symmetric sec,sec 1,2-diols and their o-isopropylidene derivatives undergo a regioselective oxidation by dimethyldioxirane depending on the electronic effects of the substituents. These results support previous views about the concerted O-insertion mechanism via a polar transition state.
- Bovicelli, Paolo,Sanetti, Anna,Lupattelli, Paolo
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p. 10969 - 10978
(2007/10/03)
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- A convenient method for the conversion of halides to alcohols
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The displacement of halides in unactivated primary bromides and iodides, allylic and benzylic primary and secondary bromides, and primary and secondary α-bromoketones by formate, using triethylammonium formate as the formylating agent, followed by acid or base catalyzed hydrolysis has been found to be an efficient method for the conversion of halides to alcohols.
- Alexander,Renyer,Veerapanane
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p. 3875 - 3881
(2007/10/03)
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- Photochemical Rearrangement of α-Chloro-Propiophenones to α-Arylpropanoic Acids: Studies on Chirality Transfer and Synthesis of (S)-(+)-Ibuprofen and (S)-(+)-Ketoprofen
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A new single-step efficient photochemical approach for α-arylpropanoic acids (4) from α-chloro-propiophenones (5) is described.It involves carbonyl triplet excited state directed 1,2-aryl migration of the aryl group which has been found to be highly dependent upon the nature of the aryl substituent.The mode of the rearrangement is probed by the study of the photobehaviour of a set of optically active α-chloro-propiophenones.The results suggest that the nature of the carbonyl triplets (n, ?*/ ?, ?*) plays an important role in the chirality transfer.This method finds application in the synthesis of optically active ibuprofen (4e) and ketoprofen (26), though in moderate optical yields.
- Sonawane, Harikisan,Bellur, Nanjundiah S.,Kulkarni, Dilip G.,Ayyangar, Nagaraj R.
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p. 1243 - 1260
(2007/10/02)
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- Light-mediated direct transformation of 2-chloropropiophenones into 2-arylpropionic acids
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A strategy based on photochemical 1,2-aryl migration as the pivotal step allows efficient transformation of 2-chloro-propiophenones into 2-arylpropionic acids. A noticeable substituent-directed excited state control on the rearrangement process has been observed.
- Sonawane, Harikisan R.,Kulkarni, Dilip G.,Ayyangar, Nagaraj R.
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p. 7495 - 7496
(2007/10/02)
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