- HIGHLY STEREOSPECIFIC PALLADIUM-CATALYSED VINYLATION OF VINYLIC HALIDES UNDER SOLID-LIQUID PHASE TRANSFER CONDITIONS.
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(E,E) and (E,Z) conjugated dienoates, dienones and dienals are obtained with high stereospecificity (95percent) and in high yields from the corresponding (E) and (Z) vinylic halides and vinylic substrates (methyl acrylate, methyl vinyl ketone or acrolein), in the presence of potassium carbonate, tetrabutylammonium chloride and a catalytic amount of palladium acetate, in N,N-dimethylformamide at room temperature.
- Jeffery, Tuyet
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- Microconine [N-methyl-2-methyl-3-methoxy-6-(deca-l’,3′,5′-trienyl)piperidine, an alkaloid from Microcos paniculata]: Synthesis, stereochemistry and spectroscopic data
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Unambiguously corrected 1H NMR data for the originally isolated sample of microconine [N-methyl-2-methyl-3-methoxy-6-(deca-l’,3′,5′-trienyl)piperidine], an alkaloid found in Microcos paniculata, are reported. The asymmetric synthesis of the (2S,3R,6S)- and (2S,3S,6S)-stereoisomeric forms [epimeric at C(3)] of this compound allows the unambiguous assignment of the relative 2,3-cis-3,6-cis-configuration of the natural product. The synthesis uses the conjugate addition of enantiopure lithium (S)-N-benzyl-N-(α-methylbenzyl)amide to tert-butyl crotonate and ensuing enolate oxidation with (+)-camphorsulfonyloxaziridine to generate the requisite C(2) and C(3) stereogenic centres found within the target. After elaboration, an intramolecular reductive amination was used to form the piperidine ring, with concomitant formation of the C(6) stereogenic centre. Comparison of specific rotation data is consistent with the alkaloid having the absolute (2R,3R,6R)-configuration.
- Davies, Stephen G.,Fletcher, Ai M.,Roberts, Paul M.,Taylor, Cameron E.,Thomson, James E.
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- 1H-pyrrole-2,4-dicarbonyl-derivatives and their use as flavoring agents
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The present invention primarily relates to 1H-pyrrole-2,4-dicarbonyl-derivatives of Formula (I) wherein R1, R2, R3, Z. Z' and J are as defined in the description, to mixtures thereof and to the use thereof as flavoring agents. The compounds in accordance with the present invention are suitable for producing, imparting, or intensifying an umami flavor. The invention further relates to flavoring mixtures, compositions for oral consumption as well as ready-to-eat, ready-to-use and semifinished products, comprising an effective amount of the compound of Formula (I) or of a mixture of compounds of Formula (I) and to specific methods for producing, imparting, modifying and/or intensifying specific flavor impressions.
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- Imidazo[1,2-a]pyridine-ylmethyl-derivatives and their use as flavoring agents
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The present invention primarily relates to imidazo[1,2-a]pyridine-ylmethyl-derivatives of Formula (I) wherein R1, R2, X, W e J are as defined in the description, to mixtures thereof and to the use thereof as flavoring agents. The compounds in accordance with the present invention are suitable for producing, imparting, or intensifying an umami flavor. The invention further relates to flavoring mixtures, compositions for oral consumption as well as ready-to-eat, ready-to-use and semifinished products, comprising an effective amount of the compound of Formula (I) and to specific methods for producing, imparting, modifying and/or intensifying specific flavor impressions.
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- Oxidative cleavage of allyl ethers by an oxoammonium salt
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A method to oxidatively cleave allyl ethers to their corresponding aldehydes mediated by an oxoammonium salt is described. Using a biphasic solvent system and mild heating, cleavage proceeds readily, furnishing a variety of α,β-unsaturated aldehydes and ketones.
- Kelly, Christopher B.,Ovian, John M.,Cywar, Robin M.,Gosselin, Taylor R.,Wiles, Rebecca J.,Leadbeater, Nicholas E.
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supporting information
p. 4255 - 4259
(2015/04/14)
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- Synthesis of naturally occurring diene and trienes by Te/Li exchange on (1Z,3Z)-butyltelluro-4-methoxy-1,3-butadiene
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(1Z,3Z)-Butyltelluro-4-methoxy-1,3-butadiene 2 was obtained by the hydrotelluration of (Z)-1-methoxy-but-1-en-3-ynes 1. The butadienyllithium 3 obtained by the Te/Li exchange reaction in the (1Z,3Z)-1-butyltelluro-4-methoxy-1,3-butadiene 2 reacted with aldehydes to form the corresponding alcohols 4a-d with total retention of configuration. The alcohols formed undergo hydrolysis, resulting in the α,β,γ,δ-unsaturated aldehydes of (E,E) configuration, which are precursors of trienes obtained from natural sources. The products of this reaction were employed in the synthesis of methyl-(2E,4E)-decadienoate 7, which is a component of the flavor principles of ripe Bartlett pears. Performing the Wittig reaction of the methyl triphenylphosphorane with the deca-(2E,4E)-dienal 5a, we were able to synthesize the undeca-(1,3E,5E)-triene 6a. This compound is a sex-pheromone component of the marine brown algae Fucus serratus, Dictyopteris plagiograma, and Dictyopteris australis. Performing the Wittig reaction of methyl triphenylphosphorane with the octa-(2E,4E)-dienal 5c, the nona-(1,3E,5E)-triene 6b was synthesized. The compound obtained is a sex-pheromone component of the marine brown alga Sargassum horneri. The octa-(1,3E,5E)-triene 6c was easily obtained from hepta-(2E,4E)-dienal 5d by the Wittig reaction with methyl triphenylphophorane. This compound is a sex-pheromone component of the marine brown alga Fucus serratus.
- Dabdoub, Miguel J.,Dabdoub, Vania B.,Baroni, Adriano C.M.,Hurtado, Gabriela R.,Barbosa, Sandro L.
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experimental part
p. 1666 - 1670
(2010/05/19)
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- Stereoselective Synthesis of 2Z,4E-Dienals by Addition of Organometallic Reagents to Pyrylium Perchlorate
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A facile and stereoselective approach to 2Z,4E-dienals and derived products is presented.The method involves addition of an organometallic reagent to a pyrylium salt, followed by electrocyclic ring-opening of the intermediate 2H-pyran, to give the desired Z,E-dienal, usually with greater than 95percent stereochemical purity.These dienals may be trapped in situ with a second organometallic reagent, or oxidised or redused, without loss of stereochemical integrity.The synthesis of (1,3Z,5E)-undeca-1,3,5-triene, a component of the essential oils of the brown Hawaiian seaweeds Dictyopteris plagiogramma and D. australis, is reported to illustrate the simplicity of the procedure.
- Furber, Mark,Herbert, John M.,Taylor, Richard J. K.
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p. 683 - 690
(2007/10/02)
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- Palladium-Catalyzed Three Carbon Chain Extension Reactions with Acrolein Acetals. A Convenient Synthesis of Conjugated Dienals
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A variety of vinylic halides has been found to react with acrolein or methacrolein acetals and amines with palladium catalysts to form 5-amino 3-enal acetals and/or dienal acetals.The reaction products yield 2,4-dienals on treatment with aqueous acids, in moderate to good yields.Crotonaldehyde dimethyl acetal also undergoes the reaction, but only in low yields. 3-Buten-2-one ethylene ketal reacted well under the same conditions, however, and Hofmann elimination and hydrolysis of the product amine gave (E,E)-3,5-heptadien-2-one in 90percent yield.
- Patel, Babu A.,Kim, Jin-Il I.,Bender, Diana D.,Kao, Lien-Chung,Heck, Richard F.
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p. 1061 - 1067
(2007/10/02)
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- An approach to the synthesis of C18 tri-insaturated fatty acids.
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New approaches for the synthesis of cis, trans, trans, octadeca-9,11,13-trienoic acid (I) and its trans, trans, cis isomer (II), starting from the easily available propargyl alcohol are described.
- Petragnani,Brocksom,Gato
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p. 627 - 634
(2007/10/12)
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