Refernces
10.1021/ol0063252
The research focuses on the efficient asymmetric synthesis of radicicol dimethyl ether, a compound derived from the metabolite of Monocillium nordinii with potential antitumor properties. The synthesis strategy is based on a convergent three-stage assembly of the 14-membered lactone, with a key transformation involving a novel ring-forming metathesis reaction using a vinyl epoxide. The synthesis process includes esterification of benzoic acid with a chiral secondary alcohol, chemoselective alkylation of an allylic dithiane, and ring-closing metathesis. Reactants used in the experiments include methyl (R)-3-hydroxybutyric acid, allylic dithiane, and substituted benzoic acid, among others. The analyses involved in the study include NMR, mass spectrometry, and various chromatographic techniques to monitor the progress and purity of the synthesized compounds. The research also discusses the challenges faced in the deprotection of the ketone and the regioselective chlorination of the aromatic ring, as well as ongoing efforts to complete the synthesis of the natural product and generate structural analogues with potential in vivo activity.
10.1107/S0108270104024424
The study focuses on the synthesis and crystal structure analysis of a mononuclear silver(I) complex, specifically bis(2-aminopyridine-xN')(benzoato-xO)silver(I), and its comparison with a polymeric 2-aminopyrimidine-Ag compound. The main objective was to investigate the relationship between the starting materials and the resulting structures, and to understand how different ligands influence the formation of metal-organic compounds. In the experiment, silver(I) oxide (Ag,O) and benzoic acid were used as starting materials to form the silver(I) complex, while 2-aminopyrimidine was employed as a tridentate ligand to obtain the polymeric compound. These chemicals served the purpose of creating distinct structural arrangements in the resulting metal-organic compounds, which were then analyzed for their crystal structures and coordination geometries. The study aimed to contribute to the understanding of inorganic supramolecular chemistry, particularly in the construction of polymeric silver(I) coordination networks, and to explore the potential of these compounds for functional solid materials with controllable properties.
10.1007/BF00953106
The research aimed to investigate the effect of Lewis acids on the decarboxylation of α-nitroalkanecarboxylic acid chlorides. The study found that aluminum chloride (AlCl?) and aluminum fluoride (AlF?) readily induce decarboxylation of these acid chlorides, with AlCl? being more effective than AlF?. The reaction, when conducted in the absence of a solvent, results in a complex mixture from which pure products cannot be isolated. However, a nitroso compound can be obtained in approximately 50% yield when the reaction is carried out in hexane. The researchers also noted that the acid chlorides do not decarboxylate in the presence of AlCl? in either absolute benzene or toluene, instead forming aromatic acids upon hydrolysis.
10.1021/jo200509m
The study investigates the rhodium-catalyzed regioselective olefination of carboxylic acids, specifically benzoic acids and related compounds. The researchers, Satoshi Mochida, Koji Hirano, Tetsuya Satoh, and Masahiro Miura, from Osaka University, Japan, developed a method to achieve ortho-olefination of benzoic acids using alkenes under rhodium catalysis, with the carboxylic group serving as a directing group. The study explores the reaction of various benzoic acids with styrenes and other alkenes, resulting in the formation of mono- and di-olefinated products. The carboxylic group can be readily removed during the reaction or post-treatment, allowing for the synthesis of a wide range of vinylarenes. The study also examines the olefination of R,β-unsaturated carboxylic acids and heteroarene carboxylic acids. The findings demonstrate that the rhodium catalyst and oxidants, such as silver or copper salts, enable efficient and regioselective olefination at the neighboring positions of the carboxylic group, providing a versatile synthetic route for constructing vinylarene derivatives.
10.1021/jo951958t
The study investigates the efficiency of the Mitsunobu reaction when using N-phenylfluorenyl or N-trityl serine esters. The researchers aimed to convert the primary alcohol of L-serine ester into various functional derivatives using the Mitsunobu reaction, but faced challenges due to the potential for β-elimination reactions. They discovered that by employing N-protecting groups like N-phenylfluorenyl and N-trityl, they could prevent this unwanted elimination reaction and achieve high yields of the desired substitution products. The study involved various nucleophiles such as benzoic acids, phenols, and imides, and demonstrated that while benzoic acids and imides reacted efficiently, phenols were less reactive. The researchers also used Mosher amide analysis to confirm that the reactions did not cause racemization, maintaining the enantiopurity of the products.
10.1021/jacs.7b04813
The research focuses on the chemoselective asymmetric intramolecular dearomatization of phenols using silver phosphate-catalyzed α-diazoacetamides. The study explores the unique reactivity of silver carbenoids, which preferentially promote dearomatization over other reactions like C–H insertion and Büchner reaction, typically catalyzed by Rh or Cu. Through experimental and computational analysis, the researchers demonstrate that silver carbenoids exhibit carbocation-like character, leading to highly enantioselective transformations. The reaction conditions were optimized using various catalysts, additives, and solvents, with benzoic acid being identified as a particularly effective additive. The substrate scope was also investigated, revealing that the method is broadly applicable to phenols with ortho-substituents, and the research provides a facile access to chiral spirolactams with all-carbon quaternary stereogenic centers. The study utilized a range of analytical techniques, including H-NMR analysis for product determination and Mosher’s ester analysis for absolute configuration determination. Computational studies involved DFT calculations to elucidate the chemoselectivity and reaction mechanisms, with a focus on the LUMO maps of Rh and Ag carbenoids.
10.1016/j.tetlet.2017.07.074
The study presents the first total synthesis of greensporone C, a cytotoxic 14-membered resorcylic acid lactone with potential biological activities such as cytotoxicity against certain cancer cell lines. The synthesis involved a 16-step linear sequence with a 3.3% overall yield. Key chemicals used in the study include Mitsunobu reagents for esterification to construct the macrocycle and establish the (E)-olefin geometry, benzoic acid derivatives and (R)-non-8-en-2-ol as key fragments for the synthesis, and various protecting groups and reagents such as ethoxymethyl (EOM), t-butyldimethylsilyl chloride (TBSCl), and iodobenzene diacetate for protecting and modifying functional groups. The purpose of these chemicals was to construct the complex structure of greensporone C, confirm its absolute stereochemistry, and potentially unlock its biological activities for further study and application.
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