58927-81-4Relevant academic research and scientific papers
Palladium-Catalyzed Enantioselective Heck Alkenylation of Acyclic Alkenols Using a Redox-Relay Strategy
Patel, Harshkumar H.,Sigman, Matthew S.
supporting information, p. 3462 - 3465 (2015/03/30)
We report a highly enantioselective intermolecular Heck reaction of alkenyl triflates and acyclic primary or racemic secondary alkenols. The mild reaction conditions permit installation of a wide range of alkenyl groups at positions β, γ, or δ to a carbonyl group in high enantioselectivity. The success of this reaction is attributed to the use of electron-withdrawing alkenyl triflates, which offer selective β-hydride elimination followed by migration of the catalyst through the alkyl chain to give the alkenylated carbonyl products. The synthetic utility of the process is demonstrated by a two-step modification of a reaction product to yield a tricyclic core structure, present in various natural products.
New volatile sulfur-containing constituents in a simultaneous distillation-extraction extract of red bell peppers (Capsicum annuum)
Naef, Regula,Velluz, Alain,Jaquier, Alain
experimental part, p. 517 - 527 (2009/04/10)
An extract of red bell peppers (Capsicum annuum) was prepared by simultaneous distillation-extraction (SDE, Likens-Nickerson). In addition to the already known (3E)-hepten-2-one (1), the unsaturated C9-ketones 1-nonen-4-one (2), (2E)-2-nonen-4-one (3), and (2E,5E)-2,5-nonadien-4-one (4), 2-methoxy-3-isobutylpyrazine (5), and heptane-2-thiol (6), we identified 19 new thiols (the aliphatic saturated and unsaturated thiols 14-16, and 22-27, the mercapto-ketones 12 and 13, the mercapto-alcohols 17, 18, and 30, the dithiols 19 and 28, the methylthio-thiols 20 and 21, and the thiophene-thiol 31) and the two new dithiolanes 10 and 29. All of them are structurally related to the unsaturated C7-and C9-ketones 1-4. The free thiols were enriched using Affi-Gel 501 (p-aminophenyl-mercuric acetate grafted on an agarose gel). The new compounds were confirmed by syntheses and were organoleptically evaluated.
In situ 1H-PHIP-NMR studies of the stereoselective hydrogenation of alkynes to (E)-alkenes catalyzed by a homogeneous [Cp*Ru]+ catalyst
Schleyer,Niessen,Bargon
, p. 423 - 426 (2007/10/03)
The hydrogenation of internal alkynes using a [Cp*Ru(alkene)]+ complex leads to the formation of (E)-alkenes. This ruthenium complex represents one of the few homogeneous catalysts that trans-hydrogenate internal alkynes directly and stereoselectively. We have studied its stereoselectivity by in situ PHIP-NMR spectroscopy (PHIP = para-hydrogen induced polarization). With this method the initially formed products can be identified and characterized even at very low concentrations and low conversions. Furthermore, their subsequent fate can be evaluated with high sensitivity and with time resolution. Different alkyne substrates were used to demonstrate the universal applicability of this catalyst. The catalyst is not active in combination with terminal alkynes, however, possibly due to the formation of a rather stable vinylidene complex. A mechanism proceeding via a binuclear complex is proposed to explain the formation of the (E)-alkenes.
Identification of a Novel Moth Sex Pheromone in Eriocrania cicatricella (Zett.) (Lepidoptera: Eriocraniidae) and its Phylogenetic Implications
Zhu, Junwei,Kozlov, Mikhail V.,Philipp, Peter,Francke, Wittko,Loefstedt, Christer
, p. 29 - 44 (2007/10/03)
Extracts from different body parts of adult female Eriocrania cicatricella (Zett.) were tested for electrophysiological activity on conspecific male antennae. Extracts from the Vth abdominal segment, containing a pair of exocrine glands, elicited the largest electroantennographic response when compared to extracts of other body parts. Female extracts were analyzed by gas chromatography with simultaneous flame ionization and electroantennographic detection (EAD). The EAD active peaks were identified as (Z)-4-hepten-2-one, (2R)-heptane-2-ol, and (2R)-(Z)-4-hepten-2-ol by coinjection on a gas chromatography and by comparison of mass spectra with those of synthetic standards. In field tests, a blend of these three pheromone components was highly attractive to conspecific males, and a subtractive assay confirmed that the unsaturated alcohol is the major pheromone component, whereas no definite behavioral activity could be assigned to the ketone or the saturated alcohol. A bait containing the two alcohols with S-configuration was attractive to male E. sparrmanella (Bosc), whereas no males of E. cicatricella were found in these traps. The sex pheromone compounds in E. cicattricella are chemically similar to pheromones reported in Trichoptera and they are produced in homologous glands.
One-Pot Synthesis of Substituted Homoallylic Alcohols (3-Alkenols) and 1-Deuterio-3-alkenols; II. Extension to Ketone Enolates
Barluenga, Jose,Alvarez, Flora,Concellon, Jose M.,Bernad, Pablo,Yus, Miguel
, p. 318 - 320 (2007/10/02)
The reaction of different lithium ketone enolates with α-chloro carbonyl compounds followed by in situ reduction with lithium aluminium hydride or deuteride and final lithiation with lithium powder leads to the corresponding homoallylic or 1-deuterio homoallylic alcohols in a regioselective manner.
TITANIUM-MEDIATED AND NEIGHBORING-GROUP ASSISTED δ-METHYLATION OF HOMOALLYL ALCOHOLS : A NEW REGIO- AND STEREOSELECTIVE CC-LINKING REACTION
Fujita, Katsuramaru,Moret, Etienne,Schlosser, Manfred
, p. 1819 - 1822 (2007/10/02)
Upon treatment with dimethyltitanium dichloride or trimethylaluminium in the presence of titanium tetrachloride, a hydrogen atom at the olefinic 4-position is replaced by a methyl group.Terminal homoallyl alcohols afford (E)-isomers.If the double bond is an internal one, the carbon chain (at the other side of the hydroxy group) leaves its original position to the enterning methyl group and switches to the other one at the same carbon atom.
