- Catalytic Enantioselective Protonation of Monofluorinated Silyl Enol Ethers towards Chiral α-Fluoroketones
-
Described herein is an organocatalytic enantioselective protonation of monofluorinated silyl enol ethers, affording an array of optically active α-secondary α-fluoroketones in good to high yields and enantioselectivities, under the catalysis of bifunction
- Liao, Kui,Hu, Xiao-Si,Zhu, Ren-Yi,Rao, Ruo-Han,Yu, Jin-Sheng,Zhou, Feng,Zhou, Jian
-
-
Read Online
- Efficient Synthesis of α-Chloroketones Catalyzed by Fluorous Hydrazine-1,2-Bis(Carbothioate) Organocatalyst
-
A novel and recoverable fluorous hydrazine-carbothioate organocatalyst was prepared. It could catalyze α-chlorination of alkyl ketones with N-chlorosuccinimide as chlorine source under mild reaction conditions. The reaction afforded the corresponding α-ch
- Zhu, Yi-Wei,Shi, Yi-Xin
-
-
Read Online
- Synthesis and biological evaluation of α-hydroxyalkylphosphonates as new antimicrobial agents
-
A set of α-quaternary 3-chloro-1-hydroxyalkylphosphonates, analogues of fosfomycin and fosfonochlorin, some of which are new compounds, was synthesized. The compounds were screened for bioactivity against several clinical and standard microbial isolates. Some were found to have moderate activity. The activity was higher with phenyl protection of the phosphoryl ester groups and α-phenyl substitution. Compound 11 was as effective or more potent than fosfomycin or chloramphenicol against several Gram-negative bacteria as well as against some Gram-positive ones.
- Faísca Phillips, Ana Maria,Barros, Maria Teresa,Pacheco, Marta,Dias, Ricardo
-
-
Read Online
- Trifluorinated Tetralins via I(I)/I(III)-Catalysed Ring Expansion: Programming Conformation by [CH2CH2] → [CF2CHF] Isosterism
-
Saturated, fluorinated carbocycles are emerging as important modules for contemporary drug discovery. To expand the current portfolio, the synthesis of novel trifluorinated tetralins has been achieved. Fluorinated methyleneindanes serve as convenient precursors and undergo efficient difluorinative ring expansion with in situ generated p-TolIF2 (>20 examples, up to >95 %). A range of diverse substituents are tolerated under standard catalysis conditions and this is interrogated by Hammett analysis. X-ray analysis indicates a preference for the CH?F bond to occupy a pseudo-axial orientation, consistent with stabilising σC?H→σC?F* interactions. The replacement of the symmetric [CH2?CH2] motif by [CF2?CHF] removes the conformational degeneracy intrinsic to the parent tetralin scaffold leading to a predictable half-chair. The conformational behavior of this novel structural balance has been investigated by computational analysis and is consistent with stereoelectronic theory.
- Daniliuc, Constantin G.,Gilmour, Ryan,Mück-Lichtenfeld, Christian,Neufeld, Jessica,Stünkel, Timo
-
supporting information
p. 13647 - 13651
(2021/05/07)
-
- Convincing Catalytic Performance of Oxo-Tethered Ruthenium Complexes for Asymmetric Transfer Hydrogenation of Cyclic α-Halogenated Ketones through Dynamic Kinetic Resolution
-
A highly efficient dynamic kinetic resolution of cyclic halohydrins was achieved by the asymmetric transfer hydrogenation of racemic α-haloketones. Bifunctional oxo-tethered Ru(II) catalysts could promote the reduction without deterioration of halogens. By structural tuning of the catalyst, chiral alcohols having halogen, ester, carboxamide, and sulfone functions were obtained variably with excellent diastereo- and enantioselectivities (up to >99:1 d.r. and >99.9 ee), which provided a concise synthetic approach to a dopamine D3 receptor ligand, (+)-PHNO.
- Touge, Taichiro,Nara, Hideki,Kida, Michio,Matsumura, Kazuhiko,Kayaki, Yoshihito
-
supporting information
p. 3070 - 3075
(2021/05/05)
-
- A Simple and Efficient Method for the Preparation of α-Halogenated Ketones Using Iron(III) Chloride and Iron(III) Bromide as Halogen Sources with Phenyliodonium Diacetate as Oxidant
-
α-Halogenated ketones are both unique structure moieties existing in biologically natural products and valuable synthetic intermediates for the preparation of functional molecules. An efficient and scalable method for the preparation of α-halogenated ketone using iron (III) chloride and iron (III) bromide as halogen sources with phenyliodonium diacetate as oxidant has been developed, featuring mild reaction conditions, environmentally friendly reagents, and wide substrate scope. Notably, the three-step synthesis of drug prasugrel was achieved using this developed method as a key step with 30% yield on gram-scale. Additionally, the reaction mechanism involving chloride cation was proposed based on some preliminary control experiments. (Figure presented.).
- Tang, Shi-Zhong,Zhao, Wenshuang,Chen, Tao,Liu, Yang,Zhang, Xiao-Ming,Zhang, Fu-Min
-
supporting information
p. 4177 - 4183
(2017/12/18)
-
- Synthesis of α-oxygenated ketones and substituted catechols via the rearrangement of N-enoxy- and N-aryloxyphthalimides
-
A common approach to the synthesis of α-oxygenated carbonyl compounds and catechols is the treatment of a carbonyl compound or a phenol with an electrophilic oxygen source. As an alternative approach to these important structures, formal [3,3]-rearrangements of N-enoxyphthalimides, N-enoxyisoindolinones, and N-aryloxyphthalimides have been explored. When used in combination with an initial Chan-Lam coupling, these transformations facilitate the dioxygenation of alkenylboronic acids for the synthesis of α-oxygenated ketones and the dioxygenation of arylboronic acids for the synthesis of catechols. The rearrangements of N-enoxyisoindolinones have also been shown to be diastereoselective.
- Kroc, Michelle A.,Patil, Aditi,Carlos, Anthony,Ballantine, Josiah,Aguilar, Stephanie,Mo, Dong-Liang,Wang, Heng-Yen,Mueller, Daniel S.,Wink, Donald J.,Anderson, Laura L.
-
p. 4125 - 4137
(2017/06/29)
-
- Mechanochemical solid-state synthesis of 2-aminothiazoles, quinoxalines and benzoylbenzofurans from ketones by one-pot sequential acid- and base-mediated reactions
-
α-Chloroketones-obtained by the atom-economical chlorination of ketones with trichloroisocyanuric acid (TCCA) in the presence of p-TSA under ball-milling conditions-were set up for a sequential base-mediated condensation reaction with thiourea/thiosemicarbazides, o-phenylenediamine and salicylaldehyde to afford 2-aminothiazoles, 2-hydrazinylthiazoles, quinoxalines and benzoylbenzofurans, respectively, in respectable yields. The viability of one-pot sequential acid- and base-mediated reactions in the solid state under ball-milling conditions is thus demonstrated.
- Nagarajaiah, Honnappa,Mishra, Abhaya Kumar,Moorthy, Jarugu Narasimha
-
p. 4129 - 4135
(2016/06/14)
-
- A simple and convenient method for direct α-chlorination of ketones with ammonium chloride and Oxone
-
When ketones were treated with ammonium chloride and Oxone in MeOH at room temperature, a direct α-chlorination of ketones was occurred and a series of the corresponding α-chloroketones were obtained in moderate to good yields after 24 h. In this reaction, ammonium chloride was used as the source of chlorine and Oxone was used as an oxidant. This method was simple, convenient and providing a novel procedure for preparation of α-chloroketones.
- Zhou, Zhong Shi,Li, Li,He, Xue Han
-
p. 1213 - 1216,4
(2020/09/16)
-
- The use of sodium chlorate/hydrochloric acid mixtures as a novel and selective chlorination agent
-
Sodium chlorate/hydrochloric acid mixtures were used to chlorinate activated arenes and the α-position of ketones. This chlorination method was used to produce selectively mono-, di-, and trichlorinated compounds by controlling the molarity of sodium chlorate. This reagent proved to be much more efficient and easier to handle than chlorine gas.
- Moon, Byung Seok,Choi, Han Young,Koh, Hun Yeong,Chi, Dae Yoon
-
experimental part
p. 472 - 476
(2011/12/04)
-
- A safe, convenient and efficient one-pot synthesis of α-chloroketone acetals directly from ketones using iodobenzene dichloride
-
Various ketones, including aliphatic and aromatic ketones, can be directly converted into their corresponding α-chloroketone acetals in high to excellent yields using iodobenzene dichloride in ethylene glycol in the presence of 4 A molecular sieves at room temperature. Georg Thieme Verlag Stuttgart.
- Yu, Jun,Zhang, Chi
-
experimental part
p. 2324 - 2328
(2010/01/13)
-
- Thiourea catalysis of NCS in the synthesis of α-chloroketones
-
Thiourea catalyzes NCS α-chlorination of alkyl ketones to provide α-chloroketones in very high yields at exceptionally rapid reaction speeds.
- Mei, Yujiang,Bentley, Paul A.,Du, Juan
-
p. 3802 - 3804
(2008/09/21)
-
- A green approach for efficient α-halogenation of β-dicarbonyl compounds and cyclic ketones using N-halosuccinimides in ionic liquids
-
Room temperature ionic liquids (ILs) are used as a green recyclable reaction media for the α-monohalogenation of 1,3-diketones, β-keto-esters and cyclic ketones with N-halosuccinimides in excellent yields in the absence of a catalyst. The recovered ionic liquid was reused five to six times with consistent activity.
- Meshram,Reddy,Vishnu,Sadashiv,Yadav
-
p. 991 - 995
(2007/10/03)
-
- 2-Chloropyridazin-3(2H)-ones as electrophilic chlorinating agents: Effective α-chlorination of active methylene/methine compounds
-
2,4,5-Trichloro- (2a) and 2,4-dichloro-5-methoxypyridazin-3(2H)-one (2b) are novel electrophilic chlorinating agents. α-Chlorination of active methylene/methine compounds with 2 in the presence of either Lewis or protonic acids in dichloromethane (for Lewis acid) or water (for protonic acid or none) at room temperature gave also selectively α-monochlorides and/or α,α-dichlorides in good to excellent yields.
- Park, Yong-Dae,Kim, Jeum-Jong,Cho, Su-Dong,Lee, Sang-Gyeong,Falck, J. Russell,Yoon, Yong-Jin
-
p. 1136 - 1140
(2007/10/03)
-
- Efficient microwave induced direct α-halogenation of carbonyl compounds
-
A novel and direct method for the synthesis of α-halocarbonyl compounds using sequential treatment of carbonyl compounds with [hydroxy(tosyloxy)iodo]benzene followed by magnesium halides under solvent-free microwave irradiation conditions is described.
- Lee, Jong Chan,Park, Jin Young,Yoon, So Young,Bae, Yong Hun,Lee, Seung Jun
-
p. 191 - 193
(2007/10/03)
-
- Transition metal-catalyzed oxidations. 12 : α-Chlorination of silylenol ethers with tert-butyl hydroperoxide and TiCl2(OiPr)2
-
Enolsilyl ethers (4, 6, 8, 10, 12, 14) are chlorinated to the α-monochloro ketones (5, 7, 9, 11, 13, 15) with tert-butyl hydroperoxide in the presence of dichlorotitanium diisopropoxide in 69 - 92% yield. WILEY-VCH Verlag GmbH, 1999.
- Krohn, Karsten,Steingroever, Klaus,Vinke, Ingeborg
-
-
- Reactions of perfluoroalkanesulfonyl chlorides with silyl enol ethers catalyzed by a ruthenium(II) phosphine complex
-
Reactions of trifluoromethane- and tridecafluorohexanesulfonyl chlorides with silyl enol ethers have been investigated in the presence of a ruthenium(II) phosphine complex. Perfluoroalkylation and chlorination occurred depending on the substituent of silyl enol ether; i.e. perfluoroalkylated compound was selectively obtained in the reactions with silyl enol ether possessing an electron-withdrawing group, on the other hand, chlorinated compounds selectively formed in the reaction with a silyl enol ether possessing electron-donating group.
- Kamigata, Nobumasa,Udodaira, Kumiko,Shimizu, Toshio
-
p. 155 - 168
(2007/10/03)
-
- PHOTOCHEMISTRY OF α-HALOCYCLOALKANONES AND α,α-DIHALOCYCLOALKANONES. IONIC AND RADICAL PHOTOCHEMICAL CARBON-HALOGEN BOND CLEAVAGE
-
The nature of the photochemical carbon-halogen bond cleavage in α-halo cycloalkanones depends on the halogen atom bonded and on the ring size of the cycloalkanone.In the 2-halo-1-indanone series the amount of radical products increased from iodine to chlorine, while in the case of 2-halo-3,4-dihydro-1(2H)-naphthalenone 43percent for iodo, 32percent for bromo, and 53percent for the chloro derivative were found.On the other hand, photochemical carbon-chlorine bond cleavage in 2,2-dichloro-1-indanone led to only radical products, while the formation of both radical and ionic products inthe ratio 1:1 was observed in the case of 2,2-dibromo-1-indanone.In the 2,2-dihalo-3,4-dihydro-1(2H)-naphthalenone series, the ratio of the radical to ionic products formed strongly depended on the halogen atom bonded: preferential formation of the radical product in the case of the chloro derivative (92percent) in contrast to 94percent of the ionic products in the case of the bromoderivative, was observed.
- Sket, Boris,Zupan, Marko
-
p. 1745 - 1752
(2007/10/02)
-