4278-79-9Relevant academic research and scientific papers
Palladium-Catalyzed Synthesis of α-Methyl Ketones from Allylic Alcohols and Methanol
Biswal, Priyabrata,Samser, Shaikh,Meher, Sushanta Kumar,Chandrasekhar, Vadapalli,Venkatasubbaiah, Krishnan
, p. 413 - 419 (2021/11/01)
One-pot synthesis of α-methyl ketones starting from 1,3-diaryl propenols or 1-aryl propenols and methanol as a C1 source is demonstrated. This one-pot isomerization-methylation is catalyzed by commercially available Pd(OAc)2 with H2O as the only by-product. Mechanistic studies and deuterium labelling experiments indicate the involvement of isomerization of allyl alcohol followed by methylation through a hydrogen-borrowing pathway in these isomerization-methylation reactions.
Experimental and Computational Studies of Palladium-Catalyzed Spirocyclization via a Narasaka-Heck/C(sp3or sp2)-H Activation Cascade Reaction
Wei, Wan-Xu,Li, Yuke,Wen, Ya-Ting,Li, Ming,Li, Xue-Song,Wang, Cui-Tian,Liu, Hong-Chao,Xia, Yu,Zhang, Bo-Sheng,Jiao, Rui-Qiang,Liang, Yong-Min
supporting information, p. 7868 - 7875 (2021/05/27)
The first synthesis of highly strained spirocyclobutane-pyrrolines via a palladium-catalyzed tandem Narasaka-Heck/C(sp3 or sp2)-H activation reaction is reported here. The key step in this transformation is the activation of a δ-C-H bond via an in situ generated σ-alkyl-Pd(II) species to form a five-membered spiro-palladacycle intermediate. The concerted metalation-deprotonation (CMD) process, rate-determining step, and energy barrier of the entire reaction were explored by density functional theory (DFT) calculations. Moreover, a series of control experiments was conducted to probe the rate-determining step and reversibility of the C(sp3)-H activation step.
Conversion of Aldehydes to Branched or Linear Ketones via Regiodivergent Rhodium-Catalyzed Vinyl Bromide Reductive Coupling-Redox Isomerization Mediated by Formate
Swyka, Robert A.,Shuler, William G.,Spinello, Brian J.,Zhang, Wandi,Lan, Chunling,Krische, Michael J.
supporting information, p. 6864 - 6868 (2019/05/10)
A regiodivergent catalytic method for direct conversion of aldehydes to branched or linear alkyl ketones is described. Rhodium complexes modified by PtBu2Me catalyze formate-mediated aldehyde-vinyl bromide reductive coupling-redox isomerization to form branched ketones. Use of the less strongly coordinating ligand, PPh3, promotes vinyl-to allylrhodium isomerization en route to linear ketones. This method bypasses the 3-step sequence often used to convert aldehydes to ketones involving the addition of pre-metalated reagents to Weinreb or morpholine amides.
Syndiotactic Poly(aminostyrene)-Supported Palladium Catalyst for Ketone Methylation with Methanol
Jiang, Lei,Guo, Fang,Shi, Zhenghai,Li, Yang,Hou, Zhaomin
, p. 3827 - 3832 (2017/09/25)
Palladium nanoparticles immobilized on an amino-functionalized syndiotactic polystyrene (sPS-N) served as a novel recyclable catalyst for the dimethylation and cross methyl alkylation of a wide range of ketones with methanol as the methylation agent. This heterogeneous catalyst (Pd@sPS-N) was highly robust and showed excellent thermal stability and chemical resistance. It not only showed remarkably high activity, but it could also be easily recovered by filtration without loss of activity.
Rhodium-catalyzed ketone methylation using methanol under mild conditions: Formation of α-branched products
Chan, Louis K. M.,Poole, Darren L.,Shen, Di,Healy, Mark P.,Donohoe, Timothy J.
supporting information, p. 761 - 765 (2014/01/23)
The rhodium-catalyzed methylation of ketones has been accomplished using methanol as the methylating agent and the hydrogen-borrowing method. The sequence is notable for the relatively low temperatures that are required and for the ability of the reaction system to form α-branched products with ease. Doubly alkylated ketones can be prepared from methyl ketones and two different alcohols by using a sequential one-pot iridium- and rhodium-catalyzed process. Uniquely effective for making branched alkyl products from ketones (see scheme): The scope of the presented reaction includes aromatic and aliphatic ketones and consecutive one-pot double alkylation reactions to provide a convenient route to branched ketones from simple methyl ketones. A brief study into the mechanism of the reaction has given evidence for an aldol-based reaction pathway.
Evolution of concise and flexible synthetic strategies for trichostatic acid and the potent histone deacetylase inhibitor trichostatin A
Cosner, Casey C.,Bhaskara Reddy Iska, Vijaya,Chatterjee, Anamitra,Markiewicz, John T.,Corden, Steven J.,Loefstedt, Joakim,Ankner, Tobias,Richer, Joshua,Hulett, Tyler,Schauer, Douglas J.,Wiest, Olaf,Helquist, Paul
, p. 162 - 172 (2013/02/23)
(R)-(+)-Trichostatic acid and (R)-(+)-trichostatin A (TSA) are natural products that have attracted considerable attention in the field of epigenetic therapies. TSA in particular is a naturally occurring hydroxamic acid having potent activity as a histone deacetylase inhibitor (HDACi) and having significant potential for treatment of a myriad of genetically based diseases. Development of TSA and other trichostatic acid derivatives into useful small-molecule therapies has been hindered by the low natural abundance and high cost associated with these compounds. We report herein our collective efforts towards the development of concise and scalable routes for the synthesis of trichostatic acid and TSA in both racemic and enantioenriched forms. Three independent synthetic pathways were developed with varying degrees of efficiency and convergency. In the first synthesis, the key step was a vinylogous Horner-Wadsworth-Emmons condensation. A Marshall propargylation reaction was used as the key step in the second synthesis, and Pd-catalyzed α-alkenylation of a ketone zinc enolate by using various functionalized alkenyl or dienyl halides was developed for the third synthesis. The second pathway proved to be readily amenable to an enantioselective modification, and both the second and third pathways were straightforwardly adapted for the facile preparation of new analogues of trichostatic acid and TSA. Three synthetic strategies have been developed for trichostatic acid and trichostatin A. Each strategy has a different key bond-forming step; a vinylogous Horner-Wadsworth-Emmons condensation, a Marshall propargylation, and coupling of a ketone enolate with various alkenyl halides. Two of the syntheses were efficient and able to produce analogues. Two of the syntheses were enantioselective. Copyright
Enantiopure C1-symmetric bis(imino)pyridine cobalt complexes for asymmetric alkene hydrogenation
Monfette, Sebastien,Turner, Zoe R.,Semproni, Scott P.,Chirik, Paul J.
supporting information; experimental part, p. 4561 - 4564 (2012/04/23)
Enantiopure C1-symmetric bis(imino)pyridine cobalt chloride, methyl, hydride, and cyclometalated complexes have been synthesized and characterized. These complexes are active as catalysts for the enantioselective hydrogenation of geminal-disubstituted olefins.
Palladium-catalyzed arylation of vinylic acetates. Phosphine ligand influenced regioselectivity
Jean, Micka?l,Renault, Jacques,Van De Weghe, Pierre
supporting information; experimental part, p. 6546 - 6548 (2011/02/23)
A palladium-catalyzed coupling reaction of aryl bromides with vinylic acetates in the presence of tributyltin methoxide h as been described. The α-arylation aldehyde product and the aryl ketone were obtained in the presence of P(t-Bu)3 and P(o-
The Allopolarization Principle and its Applications, IV. Substituent Effects in the Methylation of Enolate Anions
Gompper, Rudolf,Vogt, Hans-Hubert
, p. 2866 - 2883 (2007/10/02)
The ratio of O- and C-methylated products in the reaction of the sodium salts of acetophenones 1, propiophenones 3, phenylacetones 5, β-dicarbonyl compounds 12, α-cyanocarbonyl compounds 13, acetaldehyde, propionaldehyde, and diethylketone with dimethyl sulfate, methyl iodide, and trimethyl phosphate in HMPTA has been determined with regard to the effect of substituents.In some cases the influence of solvents, concentration and temperature has also been studied.
