- Combined Photoredox/Enzymatic C?H Benzylic Hydroxylations
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Chemical transformations that install heteroatoms into C?H bonds are of significant interest because they streamline the construction of value-added small molecules. Direct C?H oxyfunctionalization, or the one step conversion of a C?H bond to a C?O bond, could be a highly enabling transformation due to the prevalence of the resulting enantioenriched alcohols in pharmaceuticals and natural products,. Here we report a single-flask photoredox/enzymatic process for direct C?H hydroxylation that proceeds with broad reactivity, chemoselectivity and enantioselectivity. This unified strategy advances general photoredox and enzymatic catalysis synergy and enables chemoenzymatic processes for powerful and selective oxidative transformations.
- Betori, Rick C.,May, Catherine M.,Scheidt, Karl A.
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supporting information
p. 16490 - 16494
(2019/11/03)
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- Gold-catalyzed carboalkoxylations of 2-ethynylbenzyl ethers to form 1- and 3-substituted 2-methoxy-1-H-indenes: Bronsted acids versus gold catalysis
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Selective synthesis of 1- and 3-substituted 2-methoxyindenes from the carboalkoxylations of 2-ethynylbenzyl ethers is described; the former is obtained efficiently with P(t-Bu)2(o-biphenyl)AuCl/NaBARF in DCM/MS 4 ? whereas the latter is produced preferably with P(t-Bu)2(o-biphenyl)AuCl/AgNTf2 in pre-dried DCM. Both 1- and 3-substituted 2-indenyl ethers are subjected to ozone oxidations to afford two distinct carbonyl products. Our new data indicate that 1-substituted 2-indenyl ethers are generated from gold catalysts whereas their 3-substituted analogues arise from Bronsted acids.
- Chen, Chun-Hao,Wang, Chiou-Dong,Hsieh, Yi-Feng,Liu, Rai-Shung
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supporting information
p. 9831 - 9836
(2015/01/08)
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- Synthesis of diaryl ketones via a phosphine-free Fukuyama reaction
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The synthesis of unsymmetrical diaryl ketones via the Fukuyama coupling of thioesters and organozinc reagents is described. Typically, the synthesis of diaryl ketones using this methodology provides low yields. The simple complex, Pd(dba)2, was found to convert a variety of aryl thioesters to diaryl ketones in good yields. The Royal Society of Chemistry 2011.
- Kunchithapatham, Kamala,Eichman, Chad C.,Stambuli, James P.
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p. 12679 - 12681
(2012/01/05)
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- Expedient synthesis of 3-hydroxyisoquinolines and 2-hydroxy-1,4- naphthoquinones via one-pot aryne acyl-alkylation/condensation
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A convenient method is disclosed for the synthesis of both 3-hydroxyisoquinolines and 2-hydroxy-1,4-naphthoquinones from β-ketoesters using a one-pot aryne acyl-alkylation/condensation procedure. When performed in conjunction with a one-step method for the synthesis of the β-ketoester substrates, this method provides a new route to these polyaromatic structures in only two steps from commercially available carboxylic acid starting materials. The utility of this approach is demonstrated in the synthesis of the atropisomeric P,N-ligand, QUINAP. The Royal Society of Chemistry 2009.
- Allan, Kevin M.,Hong, Boram D.,Stoltz, Brian M.
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supporting information; experimental part
p. 4960 - 4964
(2010/02/15)
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- GASTRIN AND CHOLECYSTOKININ RECEPTOR LIGANDS
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This invention relates to a compound of formula (I) wherein the variables are as defined in the specification. The compound is useful for the treatment of gastrin related disorders.
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Page/Page column 27
(2010/11/30)
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- The direct acyl-alkylation of arynes
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An efficient and mild acyl-alkylation of arynes is described. The method is used to synthesize medium-sized carbocycles by the ring-expansion of cyclic β-ketoesters. Copyright
- Tambar, Uttam K.,Stoltz, Brian M.
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p. 5340 - 5341
(2007/10/03)
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- Reactions of carbonyl compounds in basic solutions. Part 21. The mechanisms of the alkaline hydrolysis of substituted methyl 2-(2-oxopropyl)- and 2-(2-oxo-2-phenylethyl)-benzoates and 2-(2-acetylphenyl)- and 2-(2-benzoylphenyl)-acetates
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Rate coefficients have been measured for the alkaline hydrolysis of methyl 2-[2-oxo-2-(3- or 4-substituted phenyl)ethyl]benzoates, 2-[2-(3- or 4-substituted benzoyl)phenyl]acetates,2-(2-oxopropyl) and 2-(1,1-dimethyl-2- oxopropyl)benzoates, 2-(2-acetylphenyl)acetate and 2-(2-acetylphenyl)-2,2- dimethylacetates in 70% (v/v) dioxane-water at 30.0 °C. Those for the six parent esters were also measured at 45.0 and 60.0 °C and the enthalpies and entropies of activation have been evaluated. The relative rates of hydrolysis, activation parameters and substituent effects have been used to demonstrate neighbouring participation by the keto-carbonyl groups in the alkaline hydrolysis of the esters under study. For comparable systems, participation by six-membered ring intermediates appears somewhat less advantageous than five-membered.
- Bowden, Keith,Byrne, Jane M.
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p. 2203 - 2206
(2007/10/03)
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- Sterically Hindered 5,11-Dicarbo Analogues of Clozapine as Potential Chiral Antipsychotic Agents
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Sterically hindered 5,11-dicarbo analogues of clozapine were prepared as potential chiral antipsychotic agents, with the possibility that for a particular analogue the antispychotic activity of clozapine may reside in one enantiomer of the analogue wherea
- Rupard, J. Howard,Paulis, Tomas de,Janowsky, Aaron,Smith, Howard E.
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p. 2261 - 2268
(2007/10/02)
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- Reaction of Ozonides with Methanol in the Presence of Chlorosulphonic Acid: Selective Cleavage of the C-O Bond of the Peroxide Bridge
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The reaction of 1,2,4-trioxolans (ozonides) (1) with methanol in the presence of chlorosulphonic acid gives good yields of products formed via the corresponding α-methoxy hydroperoxides.The order of reactivity of the ozonides, as estimated by periodic measurement of the n.m.r. spectra of a mixture of the ozonide and chlorosulphonic acid in CD3OD, is as follows: (1a), (1b) > (1c), (1d), (1e), (1f), (1g) > (1h).
- Miura, Masahiro,Nojima, Masatomo,Kusabayashi, Shigekazu
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p. 2909 - 2913
(2007/10/02)
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