- Ionic liquid catalysed synthesis of β-hydroxy ketones
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Different acidic ionic liquids (ILs; namely, 1-methylimidazolium tetrafluoroborate, 1-methylimidazolium trifluoroacetate, N-methyl-2-pyrrolidone hydrogen sulfate, N,N,N-trioctyl-n-butanesulfonic acid ammonium hydrogen sulfate, 1-methyl-3-(3-sulfobutyl)imidazolium hydrogen sulfate) and basic ILs (namely, 1,1,3,3-tetramethylguanidinium lactate and choline hydroxide) were tested as catalysts for the aldol reaction. The choline hydroxide catalysed reaction gave high yield (94.3%) and selectivity of the 4-hydroxy-4-phenylbutan- 2-one after a short reaction time (15min) at 0°C. This article demonstrates the potential of choline hydroxide, which is a derivative of choline and a naturally occurring water-soluble essential nutrient, as a highly active and selective green catalyst.
- Karmee, Sanjib Kumar,Hanefeld, Ulf
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experimental part
p. 1118 - 1123
(2012/04/17)
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- Zr(OtBu)4-catalysed synthesis of acetone aldol adducts and domino aldol-Tishchenko reactions with diacetone alcohol as enol equivalent
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Zr(OtBu)4 was found to be a potent catalyst for the synthesis of acetone aldol adducts with diacetone alcohol as enol equivalent and for domino aldol-Tishchenko reaction giving rise to 1,3-anti-diol monoesters with excellent diastereoselectivity.
- Schneider,Hansch
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p. 1218 - 1219
(2007/10/03)
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- Reaction of α-Halogeno Ketones with Carbonyl Compounds Promoted by CeI3, CeCl3-NaI,or CeCl3-SnCl2
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Reaction of α-halogeno ketones with aldehydes in the presence of CeI3 in tetrahydrofuran is found to give α,β-unsaturated ketones in excellent yields under mild conditions.In contrast, treatment of α-halogeno ketones and carbonyl compounds with CeCl3-NaI or CeCl3-SnCl2 affords β-hydroxy ketones in good yields.It is assumed that these reactions proceed via cerium enolates.The combined reagents, however, cannot be applied to a Reformatsky-type reaction.Regiospecific and aldehyde chemoselective aldol synthesis are also described.
- Fukuzawa, Shin-ichi,Tsuruta, Takuya,Fujinami, Tatsuo,Sakai, Shizuyoshi
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p. 1473 - 1478
(2007/10/02)
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- BOROHYDRIDE REDUCING AGENT DERIVED FROM ANION EXCHANGE RESIN : SELECTIVE REDUCTION OF α, β-UNSATURATED CARBONYL COMPOUNDS.
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Borohydride exchange resin (BER) exhibited selectivity in the reduction of α, β-unsaturated carbonyl compounds to the corresponding unsaturated alcohols.
- Sande, A. R.,Jagadale, M. H.,Mane, R. B.,Salunkhe, M. M.
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p. 3501 - 3504
(2007/10/02)
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