- Iridium-Catalyzed C(sp3)?H Addition of Methyl Ethers across Intramolecular Carbon–Carbon Double Bonds Giving 2,3-Dihydrobenzofurans
-
Intramolecular addition of an O-methyl C(sp3)?H bond across a carbon-carbon double bond occurs in the iridium-catalyzed reaction of methyl 2-(propen-2-yl)phenyl ethers. The Ir/(S)-DTBM-SEGPHOS catalyst promotes the reaction efficiently in toluene at 110–135 °C to afford 3,3-dimethyl-2,3-dihydrobenzofurans. Enantioselective C(sp3)?H addition is achieved in the reaction of methyl 2-(1-siloxyethenyl)phenyl ethers, affording enantioenriched 3-hydroxy-2,3-dihydrobenzofuran derivatives with up to 96% ee. (Figure presented.).
- Ohmura, Toshimichi,Kusaka, Satoshi,Torigoe, Takeru,Suginome, Michinori
-
supporting information
p. 4448 - 4453
(2019/09/16)
-
- Asymmetric Catalysis with Iron-Salen Complexes
-
Iron(III)-salen complexes based on a chiral cis-2,5-diaminobicyclo[2.2.2]octane scaffold are used as catalysts for a variety of stereo selective reactions. High enantio- and diastereoselectivities can be achieved with these catalysts in sulfa-Michael conjugate addition to acyclic α,β-unsaturated ketones, in regioselective δ-addition of thiols to acyclic α,β,γ,δ-unsaturated ketones, and in Conia-ene carbocyclization of alkynyl-substituted β-dicarbonyl compounds. The use of these chiral iron-salen complexes as catalysts provides a new method for conducting these three important reactions under environmentally sustainable conditions.
- Shaw, Subrata,White, James D.
-
p. 2768 - 2780
(2016/08/31)
-
- A new iron(III)-salen catalyst for enantioselective Conia-ene carbocyclization
-
A chiral iron(III)-salen complex based on a cis-2,5-diaminobicyclo[2.2.2]octane scaffold catalyzes asymmetric Conia-ene-type cyclization of α-functionalized ketones containing an unactivated terminal alkyne and produces an exo-methylenecycloalkane possess
- Shaw, Subrata,White, James. D.
-
p. 13578 - 13581
(2015/02/05)
-
- Practical preparation of chiral keto-imine type ONO Schiff base ligands
-
A practical preparation of chiral keto-imine type ONO Schiff base ligands has been reported. Metal complexes of these Schiff bases work as efficient chiral catalysts in a variety of asymmetric reactions.
- Dhayalan, Vasudevan,Murakami, Ryo,Hayashi, Masahiko
-
p. 543 - 547
(2013/06/27)
-
- One-pot synthesis of 3,4-disubstituted coumarins under catalysis of Mn 3O4 nanoparticles
-
The one-pot synthesis of 3,4-disubstituted coumarins from substituted 2-(hydroxymethyl)phenols with β-keto esters catalyzed by Mn 3O4 nanoparticles was developed. A series of 3,4-disubstituted coumarin derivatives were obtained in good yields. A new method for the one-pot synthesis of 3,4-disubstituted coumarins from substituted 2-(hydroxymethyl)phenols with β-keto esters catalyzed by Mn 3O4 nanoparticles has been developed. A series of 3,4-disubstituted coumarin derivatives were synthesized from substituted 2-(hydroxymethyl)phenols and β-keto esters in good yields. Copyright
- Sun, Huayin,Zhang, Yonghui,Guo, Fengfeng,Yan, Yizhe,Wan, Changfeng,Zha, Zhenggen,Wang, Zhiyong
-
supporting information; experimental part
p. 480 - 483
(2012/03/09)
-
- Phenolate and phenoxyl radical complexes of Cu(ii) and Co(iii), bearing a new redox active N,O-phenol-pyrazole ligand
-
The synthesis and characterisation of the new N,O-phenol-pyrazole pro-ligand, pzLH, comprising a pyrazole covalently linked to an o,p-di-tert-butyl-substituted phenol, are herein reported. In CH 2Cl2 at room temperature, the cyclic voltammogram (CV) of pzLH exhibits a quasi-reversible one-electron oxidation process (at E1/2 = 0.66 V vs. Fc+/Fc) attributed to the formation of the phenoxyl radical cation [pzLH]+. pzLH reacts with MII(BF4)2 (M = Cu, Co) in a 2:1 ratio to afford the bis-CupzL2 (1) and tris-Co pzL3 (2) complexes respectively. The X-ray structure of 1 reveals a Cu(ii) ion in a square-planar trans-CuII-N 2O2 coordination environment whereas that of 2 consists of a Co(iii) ion with an octahedral mer-N3O3 coordination sphere; formed by the chelation of two (in 1) or three (in 2) N,O-bidentate phenolate ligands respectively. Both structures are preserved in CH 2Cl2 solution, as revealed by their NMR (for 2) and EPR (for 1) data. The CVs of 1 and 2 consist of two (at E1/2: 0.43 and 0.58 V vs. Fc+/Fc) and three (E1/2 = 0.12, 0.54 and 0.89 V vs. Fc+/Fc) reversible one-electron oxidation processes, respectively. The one-electron electrochemical oxidation of 1 and 2 produces the oxidised species, 1+ and 2+, which are stable for several hours at room temperature under inert atmosphere in CH2Cl 2. The UV/vis and EPR data obtained for 1+ and 2 + are unambiguously consistent with the latter being formulated as Cu(ii)- and Co(iii)-phenoxyl radical complexes, as [CuII( pzL)(pzL)]+ and [CoIII( pzL)(pzL)2]+ respectively.
- Zats, Galina M.,Arora, Himanshu,Lavi, Ronit,Yufit, Dmitry,Benisvy, Laurent
-
scheme or table
p. 10889 - 10896
(2011/11/29)
-
- Convenient and efficient method for the obtainment of ketones from highly hindered aromatic N,N-dimethyl-amides
-
A simple and efficient procedure to synthesize highly hindered alkyl aryl ketones that involves the coupling of N,N-dimethyl-3,5-di-tert-butylsalicylamide with organolithium compounds is described. Mild reaction conditions and good to excellent yields of the products are the noteworthy advantages of the procedure. Copyright Taylor & Francis Group, LLC.
- Jimenez, Claudio A.,Belmar, Julio B.
-
p. 2391 - 2397
(2008/02/10)
-
- Asymmetric Syntheses of 2-(1-Aminoethyl)phenols
-
Three different routes were probed for the synthesis of enantiomerically enriched 2-(1-aminoethyl)phenols and their methyl ethers. The first route centers on diastereoselective nucleophile addition to chiral imines. The second route has as key steps the enantioselective reduction of a ketone followed by nucleophilic substitution, and the third route involves a diastereoselective imine reduction. The efficiency of the approach depends on the substrate substitution pattern. All three methods work well for the parent compound 2-(1-aminoethyl)phenol (1) but the third route is the most efficient, providing the compound with >96% enantiomer excess in three steps with an overall yield of 71%. Conversely, for the ortho-methyl analogue 2, the first method is best. For the t-Bu-substituted analogue 3, only moderate enantiomeric enrichment was achieved.
- Kuendig, E. Peter,Botuha, Candice,Lemercier, Gilles,Romanens, Patrick,Saudan, Lionel,Thibault, Sylvie
-
p. 561 - 579
(2007/10/03)
-
- Non-metallocene compounds, method for the production thereof and use of the same for the polymerisation of olefins
-
The invention relates to a method for producing special transition metal compounds, to novel transition metal compounds and to the use of the same for the polymerisation of olefins.
- -
-
-
- Novel (2E,4E,6Z)-7-(2-alkoxy-3,5-dialkylbenzene)-3-methylocta-2,4,6-trienoic acid retinoid X receptor modulators are active in models of type 2 diabetes
-
Previous data have shown that RXR-selective agonists (e.g., 3 and 4) are insulin sensitizers in rodent models of non-insulin-dependent diabetes mellitus (NIDDM). Unfortunately, they also produce dramatic increases in triglycerides and profound suppression
- Michellys,Ardecky,Chen,Crombie,Etgen,Faul,Faulkner,Grese,Heyman,Karanewsky,Klausing,Leibowitz,Liu,Mais,Mapes,Marschke,Reifel-Miller,Ogilvie,Rungta,Thompson,Tyhonas,Boehm
-
p. 2683 - 2696
(2007/10/03)
-
- Titanium(IV) chloride-mediated ortho-acylation of phenols and naphthols
-
The use of titanium(IV) chloride as a Lewis acid for direct ortho-acylation of phenols and naphthols proves to be a convenient, more general and direct route to various hydroxyaryl ketones. The route is regioselective, leading to ortho C-acylated products in satisfactory to high yields in most cases.
- Bensari, Ahlem,Zaveri, Nurulain T.
-
p. 267 - 271
(2007/10/03)
-
- Trienoic retinoid compounds and methods
-
Novel trienoic retinoid compounds having activity for retinoic acid receptors and retinoid X receptors are provided. Also provided are pharmaceutical compositions incorporating such compounds and methods for their use.
- -
-
-
- Trienoic retinoid compounds and methods
-
Novel trienoic compounds having activity for retinoic acid receptors and retinoid X receptors are provided. Also provided are pharmaceutical compositions incorporating such compounds and methods for their use.
- -
-
-
- Highly efficient preparation of optically active 5-hydroxy-3-oxoesters by enantioselective reaction of diketene with aldehydes promoted by novel chiral Schiff base-titanium alkoxide complexes
-
Optically active 5-hydroxy-3-oxoesters 1 can be obtained in up to 91% enantiomeric excess (e.e.) by the enantioselective reaction of diketene with aldehydes promoted by novel chiral Schiff base-titanium alkoxide complexes.
- Hayashi,Tanaka,Oguni
-
p. 1833 - 1836
(2007/10/03)
-
- The Metal-Promoted Fries Rearrangement
-
Upon reaction with sec-butyllithium at low temperature, o-bromophenyl esters 3 undergo an intramolecular acyl migration to produce, after hydrolysis, the corresponding o-hydroxy ketones 4.
- Miller, Joseph A.
-
p. 322 - 323
(2007/10/02)
-
- Oxygenation of tert-Butylphenols with an Unsaturated Side Chain
-
Base- and Co(Salpr)-promoted oxygenations of title compounds have been investigated with a view to obtaining further details concerning controlling factors in regioselective O2 incorporation into phenols.In the oxygenation of 4-alkenyl-2,6-di-tert-butyl- and 2-alkenyl-4,6-di-tert-butylphenols (1 and 12), the reactivity of the substrates and regioselectivity in the O2 incorporation may be interpreted in terms of electronic and steric effects of the alkenyl group as well as association effect of the countercation K+ on the transition-state 26 involving a charge transfer from the substrate anion to O2.With 4-alkynyl-2,6-di-tert-butylphenols (21), dioxygen was incorporated exclusively into the ortho position only when the phenolate anion was associated with K+.On the contrary, in the oxygenation of 1 and 12 with Co(Salpr), O2 was incorporated exclusively into the alkynyl side chain, regardless of the nature of the substituent, whereas with 21, O2 incorporation was distributed to both the ortho and the alkenyl side chain.The substituent-dependent regioselectivity in the oxygenation of phenols with Co(Salpr) is because the reactive phenolate-COIII species undergo homolysis to form phenoxy radical-CoII species reversibly, whose oxygenations compete with each other.When the oxygenation of the anionic species predominates, O2 is incorporated into the ortho position, whereas with the radical species the para and side chain oxydations predominate.
- Nishinaga, Akira,Iwasaki, Hitoshi,Shimizu, Tadashi,Toyoda, Yasushi,Matsuura, Teru
-
p. 2257 - 2266
(2007/10/02)
-
- Benzopyran-2-carboxylic acids in the prevention of asthmatic symptoms
-
There are described certain mono-chromone-2-carboxylic acids of formula, SPC1 Having one substituent in the 5 or 6 position or having 2 or more substituents in the 5,6,7 or 8 positions. There are also described processes for making the compounds and pharmacetuical compositions, for the treatment of asthma, containing the compounds.
- -
-
-