- Electrochemical Proton Reduction over Nickel Foam for Z-Stereoselective Semihydrogenation/deuteration of Functionalized Alkynes
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Selective reduction strategies based on abundant-metal catalysts are very important in the production of chemicals. In this paper, a method for the electrochemical semihydrogenation and semideuteration of alkynes to form Z-alkenes was developed, using a simple nickel foam as catalyst and H3O+ or D3O+ as sources of hydrogen or deuterium. Good yields and excellent stereoselectivities (Z/E up to 20 : 1) were obtained under very mild reaction conditions. The reaction proceeded with terminal and nonterminal alkynes, and also with alkynes containing easily reducible functional groups, such as carbonyl groups, as well as aryl chlorides, bromides, and even iodides. The nickel-foam electrocatalyst could be recycled up to 14 times without any change in its catalytic properties.
- Valiente, Alejandro,Martínez-Pardo, Pablo,Kaur, Gurpreet,Johansson, Magnus J.,Martín-Matute, Belén
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- Biosynthesis of (R)-γ-decanolactone in the yeast Sporobolomyces odorus
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Addition of [9,10-2H2]oleic acid to cultures of the yeast Sporobolomyces odorus led to the formation of labeled (R)-γ-decanolactone and both enantiomers of (Z)-6-γ-dodecenolactone and γ-dodecanolactone. The labeling patterns of these lactones were estimated by a quantitative gas chromatography/mass spectrometry method, suitable for ring-labeled lactones. For the first time, there is strong evidence of oleic acid being a genuine precursor of the important aroma compound (R)-γ-decanolactone. On the basis of the presented and former results, a new biosynthetic pathway of this compound is proposed. Starting with a strict enantioselective (R)-12-hydroxylation of oleic acid as an initial step, the following β-oxidation led to the lactone. In addition, biosynthetic aspects of the formation of (Z)-6-γ-dodecenolactone and γ-dodecanolactone in S. odorus are discussed.
- Haffner, Thomas,Tressl, Roland
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p. 1218 - 1223
(2007/10/03)
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