Trifluoromethylated enaminoketones : an entry point to organofluorine chemistry
Trifluoromethylated enaminoketones : an entry point to organofluorine chemistry
Two literature syntheses of trifluoromethylated enaminoketones were investigated; a Schreiber route utilising trifluoroacetic anhydride and a tertiary amine was found lacking in generality and reproducibility whilst the synthesis of 4-(ethyloxy)-1,1,1-trifluoro-3-buten-2-one from ethyl vinyl ether and trifluoroacetic anhydride followed by expansion of a Hojo O-N exchange reaction with an amine supplied a wide range of enaminoketones based on both monofunctional and further functionalised amines. The observed greater stability of the enaminoketones relative to their alkyloxy counterparts was used to good effect in reaction with nucleophiles; the reaction of trifluoromethylated enaminoketones with Grignard reagents led to a single trans α,β-with Grignard reagents to give a mixture of products. Also reaction of the enaminoketones with activated acetamides gave fluorinated pyridinone products whilst the ethyloxy compound was found to decompose under the reaction conditions. In contrast the ethyloxy compound reacted with enamines to give cyclic fluorinated ketones. Enaminoketones did not react under these conditions. The trifluoromethylated enaminoketones show their own individual chemistry in reaction with electrophiles to give N-alkylated and N-acetylated products in addition to products of electrophilic addition at the α-carbon. This individuality is also seen in the reaction of trifluoroacetic anhydride with amino acid based trifluoromethylated enaminoketones to yield a selection of novel β-trifluoroacetylated, β'-trifluoromethylated pyrroles not accessible using other β-functionalised, α,β-unsaturated trifluoromethylated ketones.
These findings show that trifluoromethylated enaminoketones are useful fluorinated building blocks in organofluorine chemistry as they possess a unique chemistry relative to other β-functionalised, α,β-unsaturated trifluoromethylated ketones.
University of Southampton
1998
Andrew, Rebecca Jane
(1998)
Trifluoromethylated enaminoketones : an entry point to organofluorine chemistry.
University of Southampton, Doctoral Thesis.
Record type:
Thesis
(Doctoral)
Abstract
Two literature syntheses of trifluoromethylated enaminoketones were investigated; a Schreiber route utilising trifluoroacetic anhydride and a tertiary amine was found lacking in generality and reproducibility whilst the synthesis of 4-(ethyloxy)-1,1,1-trifluoro-3-buten-2-one from ethyl vinyl ether and trifluoroacetic anhydride followed by expansion of a Hojo O-N exchange reaction with an amine supplied a wide range of enaminoketones based on both monofunctional and further functionalised amines. The observed greater stability of the enaminoketones relative to their alkyloxy counterparts was used to good effect in reaction with nucleophiles; the reaction of trifluoromethylated enaminoketones with Grignard reagents led to a single trans α,β-with Grignard reagents to give a mixture of products. Also reaction of the enaminoketones with activated acetamides gave fluorinated pyridinone products whilst the ethyloxy compound was found to decompose under the reaction conditions. In contrast the ethyloxy compound reacted with enamines to give cyclic fluorinated ketones. Enaminoketones did not react under these conditions. The trifluoromethylated enaminoketones show their own individual chemistry in reaction with electrophiles to give N-alkylated and N-acetylated products in addition to products of electrophilic addition at the α-carbon. This individuality is also seen in the reaction of trifluoroacetic anhydride with amino acid based trifluoromethylated enaminoketones to yield a selection of novel β-trifluoroacetylated, β'-trifluoromethylated pyrroles not accessible using other β-functionalised, α,β-unsaturated trifluoromethylated ketones.
These findings show that trifluoromethylated enaminoketones are useful fluorinated building blocks in organofluorine chemistry as they possess a unique chemistry relative to other β-functionalised, α,β-unsaturated trifluoromethylated ketones.
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Published date: 1998
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Local EPrints ID: 463215
URI: http://eprints.soton.ac.uk/id/eprint/463215
PURE UUID: 82c8194d-fb15-48b1-974a-0299de0214ee
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Date deposited: 04 Jul 2022 20:47
Last modified: 04 Jul 2022 20:47
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Author:
Rebecca Jane Andrew
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