Synthesis of fluoromethylated materials derived from 2-trifluoromethyl acrylic acid phenethyl ester in an ionic liquid

Salaheldin, Abdellatif M.; Yi, Zhao; Kitazume, Tomoya

doi:10.1016/j.jfluchem.2004.01.028

Cited by 13 publications

(5 citation statements)

References 24 publications

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“…Kitazume and co-workers used a stoichiometric amount of proline to promote addition of ketones to 2-trifluoromethyl acrylic acid phenethyl ester in various ionic liquids (Scheme ) . Although the yields were quite satisfactory, the diastereomeric ratio (when applicable) was close to 1:1 and no enantiomeric excess was reported.…”

Section: Ionic Liquids For Amino Acid Chemistrymentioning

confidence: 99%

Ionic Liquids: New Targets and Media for α-Amino Acid and Peptide Chemistry

et al. 2008

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Section: Ionic Liquids For Amino Acid Chemistrymentioning

confidence: 99%

Ionic Liquids: New Targets and Media for α-Amino Acid and Peptide Chemistry

et al. 2008

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“…L-Proline in combination with ionic liquids has proved to be an efficient system for Knoevenagel condensation (Wang et al, 2006), direct asymmetric aldol reactions (Loh et al, 2002;Kotrusz et al, 2002;Gruttadauria et al, 2004;Salaheldin et al, 2004), cross-aldol reactions (Córdova, 2004), Michael additions (Kitazume et al, 2003;Hagiwara et al, 2004;Kotrusz et al, 2004;Rasalkar et al, 2005), α-aminations of aldehydes and ketones (Kotrusz et al, 2005), Ullmanntype reactions , as well as Mannich reactions (Chowdari et al, 2003). To the best of our knowledge, there is no attempt of the use of L-proline as a promoter in ionic liquid for the synthesis of coumarins.…”

Section: Introductionmentioning

confidence: 99%

L-Proline as an efficient and reusable promoter for the synthesis of coumarins in ionic liquid

Liu

Fan

Liu

et al. 2008

J. Zhejiang Univ. Sci. B

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Abstract:The effect of L-proline as a promoter on the condensation reaction of salicylaldehyde or its derivatives with ethyl acetoacetate in neutral ionic liquid [emim]BF 4 was studied. All reactions were carried out under mild reaction conditions and achieved high yields. Moreover, the ionic liquid containing L-proline could be recycled and reused for several times without noticeably decreasing in productivity. The results show that the L-proline-[emim]BF 4 system has a potential in contribution to the development of environmentally friendly and inexpensive processes in organic syntheses.

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“…As for chloroacetone and 1,1-dichloroacetone, no normal alkylations appear to have been documented. Only a few aldol reactions and one Michael addition with the former have been recorded . The radical additions of xanthate 153 proceeded smoothly to give products 155 , 157 , and 160 , despite the presence of the ionically sensitive chloromethyl ketone (Scheme ).…”

Section: Alkylation Of Troublesome Ketonesmentioning

confidence: 99%

The Xanthate Route to Ketones: When the Radical Is Better than the Enolate

Zard

2018

Acc. Chem. Res.

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The alkylation of enolates is one of the backbones of ketone chemistry, yet in practice it suffers from numerous limitations due to problems of regiochemistry (including O- versus C-alkylation), multiple alkylations, self-condensation, competing elimination, and incompatibility with many polar groups that have to be protected. Over the years, various solutions have been devised to overcome these difficulties, such as the employment of auxiliary ester or sulfone groups to modify the p K of the enolizable hydrogens, the passage by the corresponding hydrazones, the use of transition-metal-catalyzed redox systems to formally alkylate ketones with alcohols, etc. Most of these hurdles disappear upon switching to α-ketonyl radicals. Radicals are tolerant of most polar functions, and radical additions to flat sp centers are generally easier to accomplish than enolate substitution at tetrahedral sp carbons. The main stumbling block, however, has been a lack of generally applicable methods for the generation and intermolecular capture of α-ketonyl radicals. We have found over the past years that the degenerative exchange of xanthates represents in many ways an ideal solution to this problem. It overcomes essentially all of the difficulties faced by other radical processes because of its unique ability to reversibly store reactive radicals in a dormant, nonreactive form. The lifetime of the radicals can therefore be significantly enhanced, even in the concentrated medium needed for bimolecular additions, while at the same time regulating their absolute and relative concentrations. The ability to perform intermolecular additions to highly functionalized alkene partners opens up numerous possibilities for rapid and convergent access to complex structures. Of particular importance is the elaboration of ketones that are prone to self-condensation, such trifluoroacetone, and of base-sensitive ketones, such as chloro- and dichloroacetone, since the products can be used for the synthesis of a myriad fluorinated and heteroaromatic compounds of relevance to medicinal chemistry and agrochemistry. The formal distal dialkylation of ketones, also of utmost synthetic interest, is readily accomplished, allowing convenient access to a wide array of useful ketone building blocks. Cascade processes can be implemented and, in alliance with powerful classical reactions (aldol, alkylative Birch reductions, etc.), furnish a quick route to complex polycyclic scaffolds. Furthermore, the presence of the xanthate group in the adducts can be exploited to obtain a variety of arenes and heteroarenes, such as pyrroles, thiophenes, naphthalenes, and pyridines, as well as enones, dienes, and cyclopropanes. Last but not least, the reagents and most of the starting materials are exceedingly cheap, and the reactions are safe and easy to scale up.

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Synthesis of fluoromethylated materials derived from 2-trifluoromethyl acrylic acid phenethyl ester in an ionic liquid

Cited by 13 publications

References 24 publications

Ionic Liquids: New Targets and Media for α-Amino Acid and Peptide Chemistry

Ionic Liquids: New Targets and Media for α-Amino Acid and Peptide Chemistry

L-Proline as an efficient and reusable promoter for the synthesis of coumarins in ionic liquid

The Xanthate Route to Ketones: When the Radical Is Better than the Enolate

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