Direct Preparation of Trifluoromethyl Ketones from Carboxylic Esters: Trifluoromethylation with (Trifluoromethyl)trimethylsilane

Wiedemann, Jürgen; Heiner, Thomas; Mlostoń, Grzegorz; Prakash, G. K. Surya; Oláh, George A.

doi:10.1002/(sici)1521-3773(19980403)37:6<820::aid-anie820>3.0.co;2-m

Cited by 142 publications

(13 citation statements)

References 6 publications

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“…Subsequent attempts to couple CF 3 -keto hydrate 3a via Wittig reaction with ylide 7, generally decomposed the substrate. Next, we explored a strategy involving the Ruppert-Prakash reagent (TMSCF 3 ), which can convert esters [26] or Weinreb amides [27] into trifluoromethyl ketones. However, these reactions generated inseparable undesired products (Scheme 2C), presumably by 1,2-addition of − CF 3 to the carbonyl of phthalimide.…”

Section: Resultsmentioning

confidence: 99%

Synthesis of Leu-enkephalin peptidomimetics containing trifluoromethylalkenes as amide isopolar mimics

Eeda

Selvaraju

Altman

2019

Journal of Fluorine Chemistry

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Fluorinated peptidomimetics are valuable substrates for exploring peptide backbone conformations and for perturbing physicochemical properties of probe compounds. However, in some cases synthetic limitations restrict installation of the fluorinated peptidomimetics into the desired probe compounds. For instance, trifluoromethylalkenes have served as amide isopolar mimics, but are rarely utilized, because many standard peptide-coupling conditions promote the isomerization of the alkene to thermodynamically favored positions. To address this challenge, we report the conversion of a naturally occurring amino acid to a Tyr 1 -ψ/[CF 3 C=CH]-Gly 2 dipeptide mimetic, and notably, successful peptide coupling reactions that avoid alkene isomerization. Using this strategy, we generated trifluoromethylalkene-containing Leu-enkephalin peptidomimetics in high purity and good yield. This sequence suggests that the trifluoromethylalkene peptidomimetics can be incorporated into other target molecules with appropriate optimization.

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Section: Resultsmentioning

confidence: 99%

Synthesis of Leu-enkephalin peptidomimetics containing trifluoromethylalkenes as amide isopolar mimics

Eeda

Selvaraju

Altman

2019

Journal of Fluorine Chemistry

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“…Likewise, TFMKs can interact with ODEs inside the sensilla where it may form stable hydrates acting as transition-state analogues of pheromones. In brief, the inhibitory activity of TFMKs is due to a stable hemiacetal of tetrahedral geometry that is formed between the conserve serine residues of the antennal esterases with the highly electrophilic carbonyl (Durán et al, 1993;Wiedemann et al, 1998). Some studies have been performed with TFMKs and electrophysiological assays in Plutella xylostella (Prestwich and Streinz, 1988), Thaumetopoea pityocampa (Parrilla and Guerrero, 1994), M. brassicae (Renou et al, 2002), Cydia pomonella (Giner et al, 2009), and S. frugiperda (Malo et al, 2013).…”

Section: Antennal Esterases Inhibition In Integrated Pest Managementmentioning

confidence: 99%

An Overview of Antennal Esterases in Lepidoptera

et al. 2021

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Lepidoptera are used as a model for the study of insect olfactory proteins. Among them, odorant degrading enzymes (ODEs), that degrade odorant molecules to maintain the sensitivity of antennae, have received less attention. In particular, antennal esterases (AEs; responsible for ester degradation) are crucial for intraspecific communication in Lepidoptera. Currently, transcriptomic and genomic studies have provided AEs in several species. However, efforts in gene annotation, classification, and functional assignment are still lacking. Therefore, we propose to combine evidence at evolutionary, structural, and functional level to update ODEs as well as key information into an easier classification, particularly of AEs. Finally, the kinetic parameters for putative inhibition of ODEs are discussed in terms of its role in future integrated pest management (IPM) strategies.

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“…With these optimized conditions in hand, a range of valuable trifluoromethyl ketones were prepared . Thus, the reaction of m - and p -anisylmagnesium bromide with ethyl trifluoroacetate ( 7 ) was complete after a residence time ( t r ) of 2 min at −5 °C in THF using an overall flow rate of 10 mL·min –1 , producing the anisyl trifluoromethyl ketones 6a – b in 65–69% isolated yield (Scheme ).…”

mentioning

confidence: 99%

Selective Acylation of Aryl- and Heteroarylmagnesium Reagents with Esters in Continuous Flow

et al. 2019

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A selective acylation of readily accessible organomagnesium reagents with commercially available esters proceeds at convenient temperatures and short residence times in continuous flow. Flow conditions allow us to prevent premature collapse of the hemiacetal intermediates despite noncryogenic conditions, thus furnishing ketones in good yields. Throughout, the coordinating ability of the ester and/or Grignard was crucial for the reaction outcome. This was leveraged by the obtention of several bisaryl ketones using 2-hydroxy ester derivatives as substrates.

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Direct Preparation of Trifluoromethyl Ketones from Carboxylic Esters: Trifluoromethylation with (Trifluoromethyl)trimethylsilane

Cited by 142 publications

References 6 publications

Synthesis of Leu-enkephalin peptidomimetics containing trifluoromethylalkenes as amide isopolar mimics

Synthesis of Leu-enkephalin peptidomimetics containing trifluoromethylalkenes as amide isopolar mimics

An Overview of Antennal Esterases in Lepidoptera

Selective Acylation of Aryl- and Heteroarylmagnesium Reagents with Esters in Continuous Flow

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