30956-41-3Relevant academic research and scientific papers
Iron-Catalyzed C(sp 3)-H Alkylation through Ligand-to-Metal Charge Transfer
Kang, Yi Cheng,Rovis, Tomislav,Treacy, Sean M.
supporting information, p. 1767 - 1771 (2021/08/20)
We report the FeCl 3-catalyzed alkylation of nonactivated C(sp 3)-H bonds. Photoinduced ligand-to-metal charge transfer at the iron center generates chlorine radicals that then preferentially abstract hydrogen atoms from electron-ric
Efficient Synthesis of Polysubstituted 1,5-Benzodiazepinone Dipeptide Mimetics via an Ugi-4CR-Ullmann Condensation Sequence
Ballet, Steven,Elsocht, Mathias,Hollanders, Charlie,Van Den Hauwe, Robin
supporting information, p. 1719 - 1724 (2021/08/20)
An efficient three-step synthesis towards 3-amino-1,4-benzodiazepin-2-one derivatives is presented. The versatile Ugi-4-component reaction (Ugi-4CR) and Boc deprotection is followed by a ligand-free Ullmann condensation. This protocol allows the rapid construction of a diverse array of substituted 1,5-benzodiazepinones. Since Ugi-based products are typically limited by their 'inert' C -terminal amides, the use of a convertible ('cleavable') isocyanide was envisaged and resulted in building blocks that can be made SPPS compatible. To demonstrate the potential of this novel synthetic route, the design and preparation of novel phenylurea-1,5-benzodiazepin-4(5 H)-one dipeptide mimetics with potential CCK2-antagonist properties is reported.
An efficient method for retro-Claisen-type C-C bond cleavage of diketones with tropylium catalyst
Hussein,Huynh,Hommelsheim,Koenigs,Nguyen
supporting information, p. 12970 - 12973 (2018/11/23)
The retro-Claisen reaction is frequently used in organic synthesis to access ester derivatives from 1,3-dicarbonyl precursors. The C-C bond cleavage in this reaction is usually promoted by a number of transition-metal Lewis acid catalysts or organic Br?nsted acids/bases. Herein we report a new convenient and efficient method utilizing the tropylium ion as a mild and environmentally friendly organocatalyst to mediate retro-Claisen-type reactions. Using this method, a range of synthetically valuable substances can be accessed via solvolysis of 1,3-dicarbonyl compounds.
Selective Synthesis of Cyclooctanoids by Radical Cyclization of Seven-Membered Lactones: Neutron Diffraction Study of the Stereoselective Deuteration of a Chiral Organosamarium Intermediate
Just-Baringo, Xavier,Clark, Jemma,Gutmann, Matthias J.,Procter, David J.
supporting information, p. 12499 - 12502 (2016/10/13)
Seven-membered lactones undergo selective SmI2–H2O-promoted radical cyclization to form substituted cyclooctanols. The products arise from an exo-mode of cyclization rather than the usual endo-attack employed in the few radical syntheses of cyclooctanes. The process is terminated by the quenching of a chiral benzylic samarium. A labeling experiment and neutron diffraction study have been used for the first time to probe the configuration and highly diastereoselective deuteration of a chiral organosamarium intermediate.
Copper-catalyzed remote sp3 C-H chlorination of alkyl hydroperoxides
Kundu, Rituparna,Ball, Zachary T.
supporting information; experimental part, p. 2460 - 2463 (2010/07/05)
A copper-catalyzed methodology to functionalize remote sp3 C-H bonds in alkyl hydroperoxides is presented. The atom-transfer chlorination utilizes simple ammonium chloride salts as the chlorine source, and the internal redox process requires no external redox reagents.
An efficient iron-catalyzed carbon-carbon single-bond cleavage via retro-claisen condensation: A mild and convenient approach to synthesize a variety of esters or ketones
Biswas, Srijit,Maiti, Sukhendu,Jana, Umasish
supporting information; experimental part, p. 2861 - 2866 (2010/08/05)
An efficient iron-salt-catalyzed carbon-carbon bond cleavage occurring through a retro-Claisen condensation reaction has been developed. The reaction is useful for the synthesis of a variety of esters or ketones under mild conditions. This method works under solvent-free conditions without the need of an inert atmosphere. This protocol is also applicable for the one-pot syntheses of ketones through tandem carbon-carbon bond formation (substitution or Michael) followed by a retro-Claisen reaction. However, for Michael adducts, ring annulation takes place subsequently. Notably, this method is very simple, convenient, high yielding, and only a catalytic (5 to 1.0 mol-%) amount of Fe(OTf)3 is needed.
Oxidation of 2-alkylcycloalkanones with iodine-cerium(IV) salts in alcohols
He, Liangyou,Kanamori, Miyuki,Horiuchi, C. Akira
, p. 122 - 123 (2007/10/03)
The reaction of 2-alkylcycloalkanones with iodine-cerium(IV) salts in alcohols (methanol, ethanol, propan-1-ol or propan-2-ol) gave the respective oxo ester in 28-98% yields.
Oxidation of 2-substituted cycloalkanones with cerium(IV) sulfate tetrahydrate in alcohols and acetic acid
He, Liangyou,Horiuchi, C. Akira
, p. 2515 - 2521 (2007/10/03)
The reaction of 2-substituted cycloalkanones with cerium(IV) sulfate tetrahydrate (CS) in alcohols and acetic acid gave the corresponding alkyl esters of oxo acids (80-96%) and oxo acids (78-96%), respectively, by oxidative cleavage of the C(R).C=O bond. In the case of 2-iodocycloalkanones in methanol, the dimethyl ester was obtained in good yield. A treatment of 5α-cholestan-3-one with CS in methanol produced 2-acetal 3-ester of 2,3-seco derivative in good yield. The effects of cerium(IV) and copper(II) salts are also discussed.
A practical method for alcohol oxidation with aqueous hydrogen peroxide under organic solvent- and halide-free conditions
Sato, Kazuhiko,Aoki, Masao,Takagi, Junko,Zimmermann, Klaus,Noyori, Ryoji
, p. 2287 - 2306 (2007/10/03)
A catalytic system consisting of sodium tungstate and methyltrioctylammonium hydrogensulfate effects oxidation of simple secondary alcohols to ketones using 3 - 30% H2O2 without any organic solvents. The oxidation can be conducted under entirely halide-free, mildly acidic conditions. A combination of tungstic acid and an appropriate quaternary ammonium salt also effects the alcohol dehydrogenation. The organic/aqueous biphasic reaction allows easy product/catalyst separation. The turnover number, defined as tools of product per mol of catalyst, approaches 77700 (2- octanol) or 179000 (1-phenylethanol), two orders of magnitude higher than any previously reported. Ester, alkyl and t-butyldimethylsilyl ether, epoxy, carbonyl, N-alkyl carboxamide, and nitrile groups are tolerated under the reaction conditions. Secondary alcohols are preferentially oxidized over terminal olefins. Primary alkanols are oxidized directly to carboxylic acids in a moderate to high yield. Benzylic alcohols are selectively oxidized to benzaldehydes or benzoic acids under suitable conditions. This method is high-yielding, clean, safe, operationally simple, and cost-effective, and therefore suitable for practical organic synthesis. The mechanistic origin of the catalytic efficiency is discussed.
Highly chemoselective, oxyvanadium-catalysed cleavage of α-hydroxy ketones
Kirihara, Masayuki,Takizawa, Shinobu,Momose, Takefumi
, p. 7 - 8 (2007/10/03)
α-Hydroxy ketones (α-ketols) can be cleaved chemoselectively with a catalytic amount of dichloroethoxyoxyvanadium under an oxygen atmosphere.
