- Regiodivergent Hydroborative Ring Opening of Epoxides via Selective C-O Bond Activation
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A magnesium-catalyzed regiodivergent C-O bond cleavage protocol is presented. Readily available magnesium catalysts achieve the selective hydroboration of a wide range of epoxides and oxetanes yielding secondary and tertiary alcohols in excellent yields and regioselectivities. Experimental mechanistic investigations and DFT calculations provide insight into the unexpected regiodivergence and explain the different mechanisms of the C-O bond activation and product formation.
- Magre, Marc,Paffenholz, Eva,Maity, Bholanath,Cavallo, Luigi,Rueping, Magnus
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supporting information
p. 14286 - 14294
(2020/09/15)
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- Hydrofunctionalization of Olefins to Higher Aliphatic Alcohols via Visible-Light Photocatalytic Coupling
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Abstract: An atomically economical green protocol for the hydrofunctionalization of olefins to higher aliphatic alcohols with 100% anti-Markovnikov regioselectivity was developed via visible-light photocatalytic coupling. This method employs cheap, readily available and abundant methanol as both the C1 feedstock and the hydrogen source under visible light irradiation over CdS photocatalyst. A wide scope of olefin substrates could be hydrofunctionalized successfully to the corresponding higher alcohols with high selectivity. Besides alcohol, acetone and acetonitrile can also couple with olefins to generate the corresponding hydrofunctionalization products, suggesting promising potential industrial application. Graphical Abstract: [Figure not available: see fulltext.] Hydrofunctionalization of olefins to value-added chemicals with high selectivity was achieved via visible-light photocatalytic cross-coupling.
- Bao, Jingxian,Fan, Yonghui,Zhang, Shuyi,Zhong, Liangshu,Wu, Minghong,Sun, Yuhan
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- Hydrofunctionalization of olefins to value-added chemicals: Via photocatalytic coupling
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A green strategy was developed for the synthesis of various value-added chemicals using methanol, acetonitrile, acetic acid, acetone and ethyl acetate as the hydrogen source by coupling them with olefins over heterogeneous photocatalysts. A radical coupling mechanism was proposed for the hydrofunctionalization of olefins with methanol to higher aliphatic alcohols over the Pt/TiO2 catalyst as the model reaction. C-H bond cleavage and C-C bond formation between photogenerated radicals and terminal olefins were accomplished in a single reaction at high efficiency. Our approach is atomically economical with high anti-Markovnikov regioselectivity and promising application potential under mild reaction conditions.
- Fan, Yonghui,Li, Shenggang,Bao, Jingxian,Shi, Lei,Yang, Yanzhang,Yu, Fei,Gao, Peng,Wang, Hui,Zhong, Liangshu,Sun, Yuhan
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supporting information
p. 3450 - 3456
(2018/08/06)
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- Tandem isomerization/hydroformylation/hydrogenation of internal alkenes to n-alcohols using Rh/Ru dual-or ternary-catalyst systems
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A one-pot three-step reaction, isomerization/hydroformylation/hydrogenation of internal alkenes to n-alcohols, was accomplished by employing a Rh/Ru dual-catalyst system. By using a combination of Rh(acac)(CO)2/ bisphosphite and Shvo's catalyst, (Z)-2-tridecene was converted to 1-tetradecanol in 83% yield with high normal/iso selectivity (n/i = 12). The method was applicable to other internal alkenes, including functionalized alkenes, such as an alkenol and an alkenoate. Furthermore, addition of a third component, Ru3(CO)12, effectively improved the n/i ratio in the tandem isomerization/hydroformylation/hydrogenation of methyl oleate (from n/i = 1.9 to 4.4). Control experiments revealed that the isomerization was mediated by both Rh and Ru and that the coexistence of Rh and Ru was essential for hydrogenation of aldehyde under H2/CO.
- Yuki, Yamato,Takahashi, Kohei,Tanaka, Yoshiyuki,Nozaki, Kyoko
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p. 17393 - 17400
(2014/01/06)
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- Small molecule probes of the receptor binding site in the Vibrio cholerae CAI-1 quorum sensing circuit
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Based on modification of separate structural features of the Vibrio cholerae quorum sensing signal, (S)-3-hydroxytridecan-4-one (CAI-1), three focused compound libraries have been synthesized and evaluated for biological activity. Modifications to the acyl tail and α-hydroxy ketone typically provided agonists with activities correlated to tail length and conservative changes to the hydroxy ketone. Among the molecules identified within this collection of agonists is Am-CAI-1 (B11), which is among the most potent agonists reported to date with an EC50 of 0.21 μM. Modifications to the ethyl side chain delivered molecules with both agonist and antagonist activity, including m-OH-Ph-CAI-1 (C13) which is the most potent antagonist reported to date with an IC50 of 36 μM. The molecules described in this manuscript are anticipated to serve as valuable tools in the study of quorum sensing in Vibrio cholerae and provide new leads in the development of an antivirulence therapy against this human pathogen.
- Bolitho, Megan E.,Perez, Lark J.,Koch, Matthew J.,Ng, Wai-Leung,Bassler, Bonnie L.,Semmelhack, Martin F.
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experimental part
p. 6906 - 6918
(2012/01/03)
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- The reactivity of epoxides with lithium 2,2,6,6-tetramethylpiperidide in combination with organolithiums or grignard reagents
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(Chemical Equation Presented) The scope and limitations of lithium 2,2,6,6-tetramethylpiperidide (LTMP)-modified reductive alkylation of epoxides is detailed. A variety of organolithiums are added to terminal and 2,2-disubstituted epoxides in the presence of LTMP to generate alkenes in a completely regio- and highly stereoselective manner. Arylated alkenes, dienes, allylsilanes, and enynes are accessed using this procedure. The methodology is applied in the synthesis of the roller leaf moth pheromone, (3E,5Z)-dodecadienyl acetate. The corresponding reaction without LTMP has also been examined, and a study using deuterated epoxides provides insight into the mechanism. In the presence of LTMP, Grignard reagents are also shown to produce E-alkenes directly from epoxides.
- Hodgson, David M.,Fleming, Matthew J.,Stanway, Steven J.
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p. 4763 - 4773
(2008/02/04)
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- Regioselective Reduction of 2,3-Epoxy Alcohol Derivatives. An Efficient Route to Enantiomerically Pure 2-Alkanols
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Reduction of 2,3-epoxy tosylates with DIBAL-H provides high yields of 2-alkanols. Key words: 2,3-epoxy tosylate; regioselective reduction; enantiomerically pure; 2-alkanol
- Chong, J. Michael
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- Preparation of Chiral Secondary Alcohols via Enantioselective Hydrolysis of Corresponding Esters with a Microorganism
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Esters of secondary alcohols were enantioselectively hydrolyzed with Brevibacterium ammoniagenes IAM 1645, ATCC 6872 to give the corresponding chiral alcohols and esters.While the esters of alkyl vinyl carbinols gave (S)-alcohols, dialkyl carbinol esters were hydrolyzed to (R)-alcohols of rather low optical purities.Hydrolysis of α-phenethyl acetate proceeded smoothly resulting in the formation of (R)-α-phenethyl alcohol in good optical yield.The structure of the acyl moiety of 1-tridecen-3-yl esters seriously influenced the rate and optical yield of the reaction, and the acetate was found to give the best results.
- Ohta, Hiromichi,Tetsukawa, Hatsuki
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p. 863 - 868
(2007/10/02)
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