- Highly selective hydroarylation of propiolic acid derivatives using a PtCl2/AgOTf catalytic system
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Hydroarylation of propiolic acid derivatives with arenes in trifluoroacetic acid efficiently proceeded in the presence of PtCl2/AgOTf catalyst to give cis-cinnamic acid derivatives in good to high yields. This PtCl2/AgOTf-catalyzed r
- Oyamada, Juzo,Kitamura, Tsugio
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Read Online
- Semireduction of alkynoic acids via a transition metal-free α borylation-protodeborylation sequence
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A method for the semi-reduction of alkynoic acids through an α-borylation and subsequent protodeborylation mechanism has been developed. The transition metal-free protocol is achieved through the activation of bis(pinacolato)diboron by an in situ generated carboxylate moiety yielding aryl acrylic acids. Our studies demonstrate an unprecedented dual role for the carboxylate anion that involves the activation of the diboron reagent and a directing effect in the α-borylation.
- Verma, Astha,Grams, R. Justin,Rastatter, Brett P.,Santos, Webster L.
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p. 2113 - 2117
(2019/02/25)
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- Catalytic hydroarylation of alkynes with arenes in the presence of FeCl3 and AgOTf
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Hydroarylation of propiolic acids with various arenes in TFA proceeded efficiently in the presence of FeCl3/AgOTf catalyst system. In the case of electron-rich arenes, the iron-catalyzed hydroarylation gave cinnamic acids in moderate to high yields. The hydroarylation of phenylacetylene was observed but the catalyst was not effective under the same conditions.
- Hashimoto, Takuya,Kutubi, Md. Shahajahan,Izumi, Takayuki,Rahman, Ataur,Kitamura, Tsugio
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experimental part
p. 99 - 105
(2011/02/16)
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- Iron(III)-catalyzed hydroarylation of propiolic acid with activated arenes
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FeCl3/AgOTf-catalyzed hydroarylation of propiolic acid with electron-rich arenes such as mesitylene, tetramethylbenzene, and pentamethylbenzene in trifluoroacetic acid proceeded to give 3-arylpropenoic acids in moderate to high yields. The same reactions with anisole and 1,4-dimethoxybenzene afforded double hydroarylation products, 3,3-diarylpropionic acids.
- Hashimoto, Takuya,Izumi, Takayuki,Kutubi, Md. Shahajahan,Kitamura, Tsugio
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scheme or table
p. 761 - 763
(2010/04/05)
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- Flash vacuum pyrolysis of stabilised phosphorus ylides. Part 10. Generation of 2-methylstyrylalkynes and their thermal cyclisation to 2-alkenylnaphthalenes
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A series of nine 2-methylcinnamoyl phosphorus ylides 7 have been prepared and are found upon FVP at 500°C to undergo loss of Ph3PO to afford the corresponding styrylalkynes 8 whose fully assigned 13C NMR spectra are presented. FVP of the ylides at 900°C leads to cyclisation to give substituted naphthalenes 9-18; the mechanism of these reactions may proceed either by initial hydrogen atom loss or an initial [1,7]hydrogen shift, but an alternative route involving an initial [1,3]hydrogen shift has been ruled out by examination of a deuterium labelled analogue. For the α-phenyl ylides 7d and 7i a further cyclisation leads to benzo[c]fluorene derivatives and this process has been extended to a thiophene analogue to give fluoreno[3,4-b]thiophene. The formation of 2-ethylnaphthalene as the main product from the α-methoxycarbonyl ylide 7e is due to a secondary thermal reaction of methyl 2-naphthylacetate which may involve a radical chain reaction featuring, as the propagation step, an unusual homolytic substitution at a methoxy carbon by a 2-naphthylmethyl radical.
- Aitken, R. Alan,Boeters, Christine,Morrison, John J.
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p. 2625 - 2631
(2007/10/03)
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- Perkin-Synthese mit Caesiumacetat
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This work demonstrates that significant higher yields and shorter reaction times in the Perkin synthesis of cinnamic acids are obtained in all cases investigated, when sodium acetate is replaced by caesium acetate.The caesium variant of the Perkin reaction described here should therefore be generally preferred
- Koepp, Erich,Voegtle, Fritz
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p. 177 - 179
(2007/10/02)
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