797756-83-3Relevant articles and documents
Synthesis of vinyl and electron-deficient aryl trifluoromethyl sulfides via Csp2?OH bond activation with AgSCF3 and n-Bu4NI/KI
Liu, Yin-Li,Xu, Xiu-Hua,Qing, Feng-Ling
supporting information, p. 5827 - 5832 (2018/09/21)
Direct dehydroxytrifluoromethylthiolation of enols and electron-deficient phenols with AgSCF3 in the presence of n-Bu4NI and KI is reported, affording a series of vinyl and aryl trifluoromethyl sulfides in moderate to excellent yields. This work represents a rare example of direct functionalization of Csp2?OH bonds.
Br?nsted acid mediated cyclizations of ortho-aryl(ethynyl)pyrimidines
Shestakov, Aleksandr N.,Pankova, Alena S.,Golubev, Pavel,Khlebnikov, Alexander F.,Kuznetsov, Mikhail A.
supporting information, p. 3939 - 3948 (2017/06/14)
A high-yielding procedure for the synthesis of 5-aryl-4-(arylethynyl)pyrimidines from easily available 2-aryl-3-hydroxyacrylates is reported. These pyrimidines readily undergo cyclization in strong Br?nsted acids and, depending on the substitution in alky
Synthesis of compounds containing a-aryl quaternary carbon centers
Alberch, Eduardo,Uddin, Nazim,Shevyrev, Maria,Hossain, M. Mahmun
, p. 139 - 146 (2012/10/30)
Acrylates 3 were synthesized following a known procedure using a Br?nsted acid catalyst, and were converted into the O-allylated products 4 in high yields. The O-allylated products 4 undergo a Claisen rearrangement in refluxing DMF for 6-24 hours, affording compounds 5 with a-aryl quaternary carbon centers in high yields.
Unusual anion effects in the iron-catalyzed formation of 3-hydroxyacrylates from aromatic aldehydes and ethyl diazoacetate
Alves, Luis Goncalo,Dazinger, Georg,Veiros, Luis F.,Kirchner, Karl
experimental part, p. 3160 - 3166 (2011/01/05)
Due to the lability of one of the CO ligands in irans-[Fe(PNP)(CO) 2Cl]+ this compound is an efficient catalyst for the coupling of a series of aromatic aldehydes with ethyl diazoacetate (EDA), which give, in most cases, selectively 3-hydroxyacrylates rather than β-oxo esters. This reaction is strongly dependent on the nature of the counterion, Whereas with BF4- the reaction proceeds with conversions up to 90%, in the case of the counterions NO3-, CF 3COO-, CF3SO3-, SbF 6-, and BAr'4- [Ar' = 3,5-(CF 3)2C6H3] no reaction took place. In the case of PF6- only up to 20% conversion was achieved. A conceivable mechanism for the coupling of aromatic aldehydes with EDA was established by means of DFT/B3LYP calculations, which allowed the rationalization of both the chemoselectivity and the role of the counterions.
Selective synthesis of α-substituted β-keto esters from aldehydes and diazoesters on mesoporous silica catalysts
Murata, Hiroaki,Ishitani, Haruro,Iwamoto, Masakazu
, p. 4788 - 4791 (2008/12/22)
The titled reactions are effectively catalyzed on mesoporous silica MCM-41 but not on amorphous silica prepared from the same starting materials as those of MCM-41. The ordered porous structure was essential to generate the acid catalysis. Planting of Al or Ti ion improved not only the catalytic activity but also the tolerance to basic functional groups of substrates. The catalytic activity of Al- or Ti-MCM-41 was better than that of SnCl2 and NbCl5 in the homogeneous phase. In particular, Al (or Ti)-MCM-41 was characteristically active for the reaction of aldehydes with α-substituted diazoesters to give 2-substituted-3-oxo propionic acid esters.
DBU-catalyzed condensation of acyldiazomethanes to aldehydes in water and a new approach to ethyl β-hydroxy α-arylacrylates
Xiao, Fengping,Liu, Yu,Wang, Jianbo
, p. 1147 - 1149 (2007/10/03)
DBU-catalyzed condensation of ethyl diazoacetate (EDA) with aldehydes in pure water afforded corresponding β-hydroxy α-diazo carbonyl compounds. The β-hydroxy group of the products was further converted into β-siloxy group. The Rh(II)-catalyzed reaction of the β-aryl β-siloxy α-diazo carbonyl compounds gave 1,2-aryl shift products predominantly. The three-step transformation constitutes an efficient synthesis of ethyl β-hydroxy α-arylacrylates.
Acid-catalyzed reactions of aromatic aldehydes with ethyl diazoacetate: An investigation on the synthesis of 3-hydroxy-2-arylacrylic acid ethyl esters
Dudley, Matthew E.,Morshed, Monzur,Brennan, Courtney L.,Islam, M. Shahidul,Ahmad, M. Syarhabil,Atuu, Mary-Rose,Branstetter, Bryan,Hossain, M. Mahmun
, p. 7599 - 7608 (2007/10/03)
Several commercial Lewis acids, including those of the Bronsted type, specifically HBF4·OEt2, are able to catalyze the reaction between aromatic aldehydes and ethyl diazoacetate to produce 3-hydroxy-2-arylacrylic acid ethyl esters and 3-oxo-3-arylpropanoic acid ethyl esters. Reactions catalyzed by the iron Lewis acid [(η5-C 5H5)Fe+(CO)2(THF)]BF 4- (i.e., 1) have the best yields and greatest ratio of 3-hydroxy-2-arylacrylic acid ethyl ester. The product distribution of 1 is not affected in the presence of Proton Sponge, but is dependent on temperature and the nature of the substrate aldehyde, whereas the activity of HBF 4-OEt2 is affected by the presence of Proton Sponge and is reactive at temperatures as low as -78 °C. Consequently, both 1 and HBF4·OEt2 are valuable catalysts in producing important 3-hydroxy-2-arylacrylic acid ethyl esters as precursors to biologically active compounds.
Iron Lewis Acid Catalyzed Reactions of Aromatic Aldehydes with Ethyl Diazoacetate: Unprecedented Formation of 3-Hydroxy-2-arylacrylic Acid Ethyl Esters by a Unique 1,2-Aryl Shift
Mahmood, Syed J.,Hossain, M. Mahmun
, p. 3333 - 3336 (2007/10/03)
The iron Lewis acid [η5-(C5H5)Fe(CO)2(THF)]BF 4 (1) was found to catalyze reactions of ethyl diazoacetate (EDA) and aromatic aldehydes, yielding 3-hydroxy-2-arylacrylie acid ethyl esters and the corresponding β-keto esters. According to the literature, this is the first report of the formation of enol esters from EDA and aromatic aldehydes. The yield of the enol esters increased with electronrich aldehydes. With 2,4-dimethoxybenzaldehyde the only product isolated was the corresponding enol ester in 80% yield. However, in the presence of electron-deficient aldehydes such as p-nitrobenzaldehyde, formation of enol ester decreased to 32%. The most unique feature of these reactions is that enol esters are formed by an unusual 1,2-aryl shift, from a possible intermediate 8, which in turn is formed from the reaction of the iron aldehyde complex 7 and EDA.
