49673-74-7Relevant academic research and scientific papers
Ir(NHC)-Catalyzed Synthesis of β-Alkylated Alcohols via Borrowing Hydrogen Strategy: Influence of Bimetallic Structure
Sung, Kihyuk,Lee, Mi-hyun,Cheong, Yeon-Joo,Kim, Yu Kwon,Yu, Sungju,Jang, Hye-Young
supporting information, p. 3090 - 3097 (2021/05/10)
Multi N-heterocyclic carbene(NHC)-modified iridium catalysts were employed in the β-alkylation of alcohols; dimerization of primary alcohols (Guerbet reaction), cross-coupling of secondary and primary alcohols, and intramolecular cyclization of alcohols. Mechanistic studies of Guerbet reaction, including kinetic experiments, mass analysis, and density functional theory (DFT) calculation, were employed to explain the fast reaction promoted by bimetallic catalysts, and the dramatic reactivity increase of monometallic catalysts at the late stage of the reaction. (Figure presented.).
Long-chain NHC-stabilized RuNPs as versatile catalysts for one-pot oxidation/hydrogenation reactions
Martínez-Prieto,Ferry,Rakers,Richter,Lecante,Philippot,Chaudret,Glorius
supporting information, p. 4768 - 4771 (2016/04/09)
The synthesis and catalytic activity of long-chain NHC-stabilized RuNPs are presented. Full characterization of these novel nanostructures including surface state studies show that the ligand influences the number and the location of Ru active sites which impacts the NP catalytic activity, especially in hydrogenation reactions. The high stability and versatility of these nanosystems make them successful catalysts for both oxidation and hydrogenation reactions that can even be performed successively in a one pot-fashion.
Stereoselective synthesis of carbocyclic analogues of the nucleoside Q precursor (PreQ0)
Llona-Minguez, Sabin,Mackay, Simon P.
supporting information, p. 1333 - 1338 (2014/07/22)
A convergent and stereoselective synthesis of chiral cyclopentyl- and cyclohexylamine derivatives of nucleoside Q precursor (PreQ0) has been accomplished. This synthetic route allows for an efficient preparation of 4-substituted analogues with
Highly enantio- and s-trans C=C bond selective catalytic hydrogenation of cyclic enones: Alternative synthesis of (-)-menthol
Ohshima, Takashi,Tadaoka, Hiroshi,Hori, Kiyoto,Sayo, Noboru,Mashima, Kazushi
scheme or table, p. 2060 - 2066 (2009/04/07)
A highly enantioselective catalytic hydrogenation of cyclic enones was achieved by using the combination of a cationic Rh1 complex, (S)-5,5′-bis{di(3,5-di-tert-butyl-4-methoxyphenylphosphino)}-4, 4′-bi-1,3-benzodioxole (DTBM-SEGPHOS), and (CH2CH 2PPh3Br)2. The presence of an s-cis C=C bond isopropylidene moiety on the cyclic enone influenced the enantioselectivity of the hydrogenation. Thus, the hydrogenation of 3-alkyl-6-isopropylidene-2- cyclohexen-1-one, which contains both s-cis and s-trans enones, proceeded in excellent enantioselectivity (up to 98% ee). To obtain high enantio- and s-trans selectivities, the addition of a halogen source to the cationic Rh complex was the essential step. With the key step of the s-trans selective asymmetric hydrogenation of piperitenone, we demonstrated a new synthetic method for optically pure (-)-menthol via three atom-economical hydrogenations. Moreover, we found that the complete s-trans and s-cis C=C bond selective reactions were also realized by the proper choice of both the chiral ligands and halides.
Selective electrochemical reduction of cinnamyl ethers in the presence of other allylic C-O bonds
Solis-Oba, Aida,Hudlicky, Tomas,Koroniak, Lukasz,Frey, Dean
, p. 1241 - 1243 (2007/10/03)
Several conduritol derivatives protected as allyl and cinnamyl ethers were subjected to electrochemical reduction at a mercury cathode, resulting in selective removal of the cinnamyl group.
A new paradigm for biohydroxylation by Beauveria bassiana ATCC 7159
Holland, Herbert L.,Morris, Terence A.,Nava, Phillip J.,Zabic, Mirjana
, p. 7441 - 7460 (2007/10/03)
The biohydroxylation of a series of amides and related amino, keto and hydrocarbon substrates by the fungal biocatalyst Beauveria bassiana ATCC 7159 has been examined. The product distributions, together with data obtained from selective inhibition experiments using the cyt.P-450 inhibitors isosafrole, 1-aminobenzotriazole and phenylacetylene, suggest that B. bassiana contains a range of hydroxylase enzymes with different substrate specificities. A paradigm is presented for the interpretation of the results of microbial hydroxylation and for the application of existing active site models for B. bassiana.
Biohydroxylation reactions catalyzed by enzymes and whole-cell systems
Flitsch, Sabine L.,Aitken, Suzanne J.,Chow, Cathy S.-Y.,Grogan, Gideon,Staines, Adam
, p. 81 - 90 (2007/10/03)
The biohydroxylation of a number of cyclic substrates (3-24) containing aromatic side chains was used to compare substrate specificity and selectivity of hydroxylation using microbial enzymes and whole-cell biocatalysts. In general, the regioselectivity of reaction was remarkably similar between the different catalysts in that little aromatic or benzylic, but significant aliphatic hydroxylation was observed. However, a more detailed investigation of isolated products showed complementary substrate specificity, functional group compatibility, and regioselectivity of hydroxylation. Substrate specificity and regioselectivity could be further modulated by small changes to the nature of the aromatic side chain, which appears to play an important role in substrate recognition.
Lipase-mediated diastereoselective and enantioselective acetylations of 3-substituted cyclohexanols
Tanikaga, Rikuhei,Morita, Akira
, p. 635 - 638 (2007/10/03)
Lipase-mediated acetylation of four diastereomeric and enantiomeric isomers of 3-substituted cyclohexanols 2 has led to an efficient resolution to provide a single stereoisomer, (1R,3S)-cyclohexyl acetate (1R,3S)-3 in a high enantiomeric excess.
Aliphatic vs. aromatic C-H bond activation of phenylcyclohexane catalysed by cytochrome P450cam
England, Paul A.,Rouch, Duncan A.,Westlake, Andrew C. G.,Bell, Stephen G.,Nickerson, Darren P.,Webberley, Matthew,Flitsch, Sabine L.,Wong, Luet-Lok
, p. 357 - 358 (2007/10/03)
Catalytic hydroxylation of phenylcyclohexane 1 by wild-type and the Y96A and Y96F mutant forms of cytochrome P450cam occurs only at the 3- and 4-positions on the cyclohexane ring, giving cis-3-phenylcyclohexanol 2, cis-4-phenylcyclohexanol 3 and trans-4-phenylcyclohexanol 4.
Hydroxy-Directed Hydroaluminations: A Stereoselective Approach to Cycloalkanols From β-Aryl Enones.
Koch, Kevin,Smitrovich, Jacqueline H.
, p. 1137 - 1140 (2007/10/02)
Various aryl substituted enones are reduced using lithium aluminum hydride to afford sterioselectively trans substituted alkanols.Mechanistic studies demonstrate 1,2-addition followed by hydroxy-directed hydroalumination of the conjugated styryl unit.
