- Visible Light Enabled Formal Cross Silyl Benzoin Reaction as an Access to α-Hydroxyketones
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In this work, a visible-light enabled coupling of acylsilanes with aldehydes to give a range of cross-benzoin type products α-hydroxyketones is described. The reaction could proceed at ambient temperature, with the irradiation of low energy visible light, and without addition of photosensitizer or any other additives. (Figure presented.).
- Ma, Liyao,Yu, Yinghua,Xin, Luoting,Zhu, Lei,Xia, Jiajin,Ou, Pengcheng,Huang, Xueliang
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supporting information
p. 2573 - 2577
(2021/04/05)
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- Synthesis of chiral α-diarylacetic esters by stereospecific 1,2-aryl migration promoted by in situ generated acetals from benzoins
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A simple protocol for the synthesis of α-diarylacetic esters from benzoins is described. In situ generated acetal assists rapid 1,2-aryl migration in a stereospecific manner, paving the way to make enantioenriched α-diarylacetic esters from easily accessi
- Kothapalli, Raveendra Babu,Niddana, Ramana,Balamurugan, Rengarajan
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supporting information
p. 1278 - 1281
(2014/04/03)
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- Synthesis and SAR study of 4,5-diaryl-1H-imidazole-2(3H)-thione derivatives, as potent 15-lipoxygenase inhibitors
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A series of 4,5-diaryl-1H-imidazole-2(3H)-thione was synthesized and their inhibitory potency against soybean 15-lipoxygenase and free radical scavenging activities were determined. Compound 11 showed the best IC50 for 15-LOX inhibition (IC50 = 4.7 μM) and free radical scavenging activity (IC50 = 14 μM). Methylation of SH at C2 position of imidazole has dramatically decreased the 15-LOX inhibition and radical scavenging activity as it can be observed in the inactive compound 14 (IC50 >250 μM). Structure activity similarity (SAS) showed that the most important chemical modification in this series was methylation of SH group and Docking studies revealed a proper orientation for SH group towards Fe core of the 15-LOX active site. Therefore it was concluded that iron chelating could be a possible mechanism for enzyme inhibition in this series of compounds.
- Assadieskandar, Amir,Amini, Mohsen,Salehi, Marjan,Sadeghian, Hamid,Alimardani, Maliheh,Sakhteman, Amirhossein,Nadri, Hamid,Shafiee, Abbas
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p. 7160 - 7166
(2013/01/15)
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- Chemoenzymatic synthesis of chiral unsymmetrical benzoin esters
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A chemoenzymatic Dynamic Kinetic Resolution (DKR) of unsymmetrical benzoins (Ar1≠Ar2) has been carried out, by using Pseudomonas stutzeri lipase stereorecognition pattern. After studying this lipase behaviour, a high preference towards acylation of those benzoins containing substituents in the phenyl ring rather than in the benzoyl moiety was observed. This fact allowed the development of the DKR process of this kind of substrates, avoiding the accumulation of secondary products derived from the in situ racemization mediated by Shvo's catalyst action, and allowing the synthesis of enantiopure unsymmetrical benzoins acetates (not previously described) in very good yields (60-95%) and excellent enantiomeric excess values (always >99%).
- Hoyos, Pilar,Pace, Vittorio,Sinisterra, José V.,Alcántara, Andrés R.
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experimental part
p. 7321 - 7329
(2011/10/09)
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- Mechanism and scope of the cyanide-catalyzed cross silyl benzoin reaction
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In this work, cross silyl benzoin addition reactions between acylsilanes (1) and aldehydes (2) catalyzed by metal cyanides are described. Unsymmetrical aryl-, heteroaryl-, and alkyl-substituted benzoin adducts can be generated in moderate to excellent yie
- Linghu, Xin,Bausch, Cory C.,Johnson, Jeffrey S.
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p. 1833 - 1840
(2007/10/03)
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- Cross silyl benzoin additions catalyzed by lanthanum tricyanide
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From a screen of (cyanide)metal complexes, an improved catalyst for the cross silyl benzoin addition was discovered. Several M(CN)3 complexes (M = Ce, Er, Sm, Y, Yb, La) were evaluated and lanthanum tricyanide was identified as the optimal cata
- Bausch, Cory C.,Johnson, Jeffrey S.
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p. 4283 - 4285
(2007/10/03)
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- Direct Formation of Benzoins from Diarylmethanones via a Rearrangement Reaction Promoted by Samarium Metal in DMF
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Diarylmethanones react readily with DMF when promoted by samarium metal in DMF with TMSCl or iodine as an activator, to afford benzoins in good to excellent yields via rearrangement of aryl groups. As for asymmetric diarylmethanones, products resulting from the migration of either aryl group were obtained, where the migration of aryl groups shows certain priority.
- Liu, Yongjun,Xu, Xiaoliang,Zhang, Yongmin
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p. 445 - 448
(2007/10/03)
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- Samarium reagent-promoted formation of benzoins from diarylmethanones and DMF via a carbene rearrangement reaction
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Prompted by samarium metal in DMF with TMSCl or iodine as an activator, or by SmI2/THF system, diarylmethanones react readily with DMF to afford benzoins in moderate to good yields via rearrangement of aryl groups. As for asymmetric diarylmethanones, products resulting from the migration of either aryl group were obtained, where the migration of aryl groups shows certain priority.
- Liu, Yongjun,Xu, Xiaoliang,Zhang, Yongmin
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p. 4867 - 4873
(2007/10/03)
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- Reductive Coupling of Benzoyl Cyanide and Carbonyl Compounds by Aqueous Ti(III) Ions. A New Convenient and Selective Access to the Less Stable Mixed Benzoins
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The reactive species formed by the Ti(III) ion reduction of benzoyl cyanide (1) adds to the C-atom of carbonyl compounds 2 under simple experimental conditions.The intermediate 1,2-diols 3 are smoothly converted, without isolation, into the less thermodynamically stable mixed benzoins 4, which are not accessible by the classical benzoin condensation.The possible mechanisms involved in the reaction are discussed.
- Clerici, Angelo,Porta, Ombretta
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p. 2889 - 2893
(2007/10/02)
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- Reduction of Unsymmetrical Benzils Using Sodium Dithionite
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Contrary to a previous report, reduction of unsymmetrical benzils by sodium dithionite (sodium hydrosulfite) in general yields a mixture of isomeric benzoins.Whereas the reduction of aldehydes and ketones by dithionite apparently takes place by a nucleophilic addition mechanism, the reduction of benzils proceeds by an electron-transfer mechanism.The initial product of the reduction is the (Z)-α,α'-stilbenediol which is produced stereospecifically.The ultimate benzoin products, then, result from the two different modes of ketolization of the stilbenediol intermediate.
- Heilmann, Steven M.,Rasmussen, Jerald K.,Smith, Howell K.
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p. 987 - 992
(2007/10/02)
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- ADDITION OF GRIGNARD REAGENTS TO O-TRIMETHYLSILYLATED CYANOHYDRINS: SYNTHESIS OF ACYLOINS
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Grignard reagents have been found to react readily with O-trimethylsilylated cyanohydrins to afford, after acid hydrolysis of intermediates, good yields of acyloins.
- Krepski, Larry R.,Heilmann, Steven M.,Rasmussen, Jerald K.
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p. 4075 - 4078
(2007/10/02)
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- A New Type of P-C and C-C Bond Cleavage Reactions in α-Trimethylsilyloxy-β-oxo Phosphonates and α-Ethoxy-β-oxo Phosphonates. The Synthesis of Unsymmetrical α-Hydroxy Ketones Utilizing 1:1 Carbonyl Adducts of Diethyl Trimethylsilyl Phosphite with Benzaldehyde
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α-Lithiated diethyl α-(trimethylsilyloxy)benzylphosphonate underwent facile acylation with various acylating agents to afford the corresponding α-acylated products in good yields.On treatment with the α-acylated products with 1 M NaOH-EtOH (1:1, v/v) the P-C bond was cleaved with elimination of diethyl phosphate to give α-hydroxy ketones predominantly.On the other hand, when diethyl α-acyl-α-ethoxybenzylphosphonates were treated under the same conditions, they were rather stable and recovered.However, the prolonged alkaline treatment or the use of 4 M NaOH-EtOH (1:1 v/v) resulted in the C-C bond cleavage giving carboxylic acids and diethyl α-ethoxybenzylphosphonate in quantitative yields, respectively.The mechanisms of the above two reactions were proposed and discussed in connection with the Perkow reaction and related reactions.
- Sekine, Mitsuo,Nakajima, Masashi,Hata, Tsujiaki
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p. 218 - 223
(2007/10/02)
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