Isothiourea HBTM-2.1 promotes the catalytic asymmetric α-functionalization of 3-alkenoic acids through formal [2 + 2] cycloadditions with N-tosyl aldimines and formal [4 + 2] cycloadditions with either 4-aryltrifluoromethyl enones or N-aryl-N-aroyl diazenes, providing useful synthetic building blocks in good yield and with excellent enantiocontrol (up to >99% ee). Stereodefined products are amenable to further synthetic elaboration through manipulation of the olefinic functionality.
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http://dx.doi.org/10.1021/jo402591v | DOI Listing |
J Agric Food Chem
March 2018
Professorship of Aroma Research, Department of Chemistry and Pharmacy, Emil Fischer Center , Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Henkestrasse 9 , 91054 Erlangen , Germany.
( Z)-3-Unsaturated volatile acids, alcohols, and aldehydes are commonly found in foods and other natural sources, playing a vital role in the attractiveness of foods but also as compounds with chemocommunicative function in entomology. However, a systematic investigation of their smell properties, especially regarding humans, has not been carried out until today. To close this gap, the odor thresholds in air and odor qualities of homologous series of ( Z)-3-alken-1-ols, ( Z)-3-alkenals, and ( Z)-3-alkenoic acids were determined by gas chromatography-olfactometry.
View Article and Find Full Text PDFJ Agric Food Chem
August 2015
†Department of Chemistry and Pharmacy, Emil Fischer Center, Friedrich-Alexander-Universität Erlangen-Nürnberg, Schuhstrasse 19, 91052 Erlangen, Germany.
(E)-3-Unsaturated volatile acids, alcohols, and aldehydes are commonly found as odorants or pheromones in foods and other natural sources, playing a vital role in not only the attractiveness of foods but also chemo-communication in the animal kingdom. However, a systematic elucidation of their aroma properties, especially for humans, has not been carried out until today. To close this gap, the odor thresholds in air and odor qualities of homologous series of (E)-3-alkenoic acids, (E)-3-alken-1-ols, and (E)-3-alkenals were determined by gas chromatography-olfactometry.
View Article and Find Full Text PDFJ Org Chem
February 2014
EaStCHEM, School of Chemistry, University of St Andrews, North Haugh, St Andrews, KY16 9ST, U.K.
Isothiourea HBTM-2.1 promotes the catalytic asymmetric α-functionalization of 3-alkenoic acids through formal [2 + 2] cycloadditions with N-tosyl aldimines and formal [4 + 2] cycloadditions with either 4-aryltrifluoromethyl enones or N-aryl-N-aroyl diazenes, providing useful synthetic building blocks in good yield and with excellent enantiocontrol (up to >99% ee). Stereodefined products are amenable to further synthetic elaboration through manipulation of the olefinic functionality.
View Article and Find Full Text PDFChemistry
July 2013
The Institute of Scientific and Industrial Research, Osaka University, 8-1 Mihogaoka, Ibaraki, Osaka 567-0047, Japan.
The reaction pathway of an enantioselective 5-endo-trig-type cyclization of 3-alkenoic acids catalyzed by a chiral palladium-spiro-bis(isoxazoline) complex, Pd-SPRIX, has been studied by density functional theory calculations. The most plausible pathway involves intramolecular nucleophilic attack of the carboxylate moiety on the C=C double bond activated by Pd-SPRIX and β-H elimination from the resulting organopalladium intermediate. The enantioselectivity was determined in the cyclization step through the formation of a π-olefin complex, in which one of the two enantiofaces of the olefin moiety was selected.
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