176848-41-2Relevant academic research and scientific papers
Enantioselective microbial oxidation of allyl alcohols
Matsumoto, Kazutsugu,Kawabata, Yoichi,Okada, Satoshi,Takahashi, Jun,Hashimoto, Key,Nagai, Yuto,Tatsuta, Junichi,Hatanaka, Minoru
, p. 1428 - 1429 (2007)
A new route to the optically active allyl alcohols by microbial oxidation is disclosed. Yamadazyma farinosa IFO 10896, a yeast, efficiently catalyzes the enantioselective oxidation of allyl alcohols to afford the corresponding optically active alcohols as the remaining substrates. This reaction is applicable to both cyclic and acyclic compounds. Copyright
Evidence That Protons Can Be the Active Catalysts in Lewis Acid Mediated Hetero-Michael Addition Reactions
Wabnitz, Tobias C.,Yu, Jin-Quan,Spencer, Jonathan B.
, p. 484 - 493 (2004)
The mechanism of Lewis acid catalysed hetero-Michael addition reactions of weakly basic nucleophiles to α,β-unsaturated ketones was investigated. Protons, rather than metal ions, were identified as the active catalysts. Other mechanisms have been ruled out by analyses of side products and of stoichiometric enone-catalyst mixtures and by the use of radical inhibitors. No evidence for the involvement of π-olefin-metal complexes or for carbonyl-metal-ion interactions was obtained. The reactions did not proceed in the presence of the non-coordinating base 2,6-di-tert-butylpyridine. An excellent correlation of catalytic activities with cation hydrolysis constants was obtained. Different reactivities of mono- and dicarbonyl substrates have been rationalised. A 1H NMR probe for the assessment of proton generation was established and Lewis acids have been classified according to their propensity to hydrolyse in organic solvents. Bronsted acid-catalysed conjugate addition reactions of nitrogen, oxygen, sulfur and carbon nucleophiles are developed and implications for asymmetric Lewis acid catalysis are discussed.
Oxa-Michael addition promoted by the aqueous sodium carbonate
Guo, Shi-Huan,Xing, Sheng-Zhu,Mao, Shuai,Gao, Ya-Ru,Chen, Wen-Liang,Wang, Yong-Qiang
supporting information, p. 6718 - 6720 (2014/12/11)
An efficient Michael addition of alcohols to activated alkenes promoted by sodium carbonate with water as reaction medium has been developed. The reaction provides a general, economical and environmentally friendly approach for the synthesis of β-alkoxycarbonyl compounds.
Ti(II)-mediated conversion of α-heterosubstituted (O, N, S) nitriles to functionalized cyclopropylamines. Effect of chelation on the cyclopropanation step
Bertus, Philippe,Szymoniak, Jan
, p. 3965 - 3968 (2007/10/03)
α-Alkoxy, amino-, and thio nitriles undergo a Ti(II)-mediated coupling with Grignard reagents to afford heterofunctionalized cyclopropylamines. A chelation effect appears to be generally responsible for the spontaneous contraction of the intermediate azatitanacycle leading to cyclopropane. By using the described reaction, 1-aminocyclopropanecarboxylic acids were prepared in four steps, in good overall yields, from the readily available benzyloxyacetonitrile.
Temperature-dependent isomerisation versus net fragmentation of secondary allylic alcohols with Grubbs' catalyst
Gurjar, Mukund K.,Yakambram, Pedduri
, p. 3633 - 3636 (2007/10/03)
Secondary allylic alcohols with 10 mol% of Grubbs catalyst in refluxing toluene/1,2-dichloroethane undergo isomerisation to ethyl ketones whereas with 100 mol% of Grubbs catalyst at room temperature, a net fragmentation reaction with the loss of a carbon atom occurs, to provide a methyl ketone. Probable mechanisms are described.
3-Benzyloxy-1-isocyanopropenes. Synthesis and use as 3-hydroxypropanoyl anion equivalents
Kobayashi, Kazuhiro,Akamatsu, Hideki,Takada, Keiichiro,Morikawa, Osamu,Konishi, Hisatoshi
, p. 2437 - 2440 (2007/10/03)
New acyl anion equivalents bearing a hydroxyl group at the β-position have been developed. Treatment of 3-benzyloxy-1-isocyanopropenes with lithium diisopropylamide (LDA) in THF at -78°C generated the 1-lithio compounds, which reacted with alkyl halides to afford the corresponding 1-alkylated products in good yields. Acid hydrolysis of these alkylated products followed by hydrogenolysis of the resulting β-benzyloxyethyl ketones led to β-hydroxyethyl ketones.
