57625-76-0Relevant academic research and scientific papers
Siloxy Esters as Traceless Activators of Carboxylic Acids: Boron-Catalyzed Chemoselective Asymmetric Aldol Reaction**
Fujita, Taiki,Kanai, Motomu,Mitsunuma, Harunobu,Sameera, W. M. C.,Yamane, Mina
supporting information, p. 24598 - 24604 (2021/10/14)
The catalytic asymmetric aldol reaction is among the most useful reactions in organic synthesis. Despite the existence of many prominent reports, however, the late-stage, chemoselective, catalytic, asymmetric aldol reaction of multifunctional substrates is still difficult to achieve. Herein, we identified that in situ pre-conversion of carboxylic acids to siloxy esters facilitated the boron-catalyzed direct aldol reaction, leading to the development of carboxylic acid-selective, catalytic, asymmetric aldol reaction applicable to multifunctional substrates. Combining experimental and computational studies rationalized the reaction mechanism and led to the proposal of Si/B enediolates as the active species. The silyl ester formation facilitated both enolization and catalyst turnover by acidifying the α-proton of substrates and attenuating poisonous Lewis bases to the boron catalyst.
Iodoarene-Catalyzed Oxyamination of Unactivated Alkenes to Synthesize 5-Imino-2-Tetrahydrofuranyl Methanamine Derivatives
Deng, Xiao-Jun,Liu, Hui-Xia,Zhang, Lu-Wen,Zhang, Guan-Yu,Yu, Zhi-Xiang,He, Wei
, p. 235 - 253 (2021/01/09)
Reported here is the room-temperature metal-free iodoarene-catalyzed oxyamination of unactivated alkenes. In this process, the alkenes are difunctionalized by the oxygen atom of the amide group and the nitrogen in an exogenous HNTs2 molecule. This mild and open-air reaction provided an efficient synthesis to N-bistosyl-substituted 5-imino-2-tetrahydrofuranyl methanamine derivatives, which are important motifs in drug development and biological studies. Mechanistic study based on experiments and density functional theory calculations showed that this transformation proceeds via activation of the substrate alkene by an in situ generated cationic iodonium(III) intermediate, which is subsequently attacked by an oxygen atom (instead of nitrogen) of amides to form a five-membered ring intermediate. Finally, this intermediate undergoes an SN2 reaction by NTs2 as the nucleophile to give the oxygen and nitrogen difunctionalized 5-imino-2-tetrahydrofuranyl methanamine product. An asymmetric variant of the present alkene oxyamination using chiral iodoarenes as catalysts also gave promising results for some of the substrates.
Isomerization of olefins triggered by rhodium-catalyzed C-H bond activation: Control of endocyclic β-hydrogen elimination
Yip, Stephanie Y. Y.,A?ssa, Christophe
supporting information, p. 6870 - 6873 (2015/06/02)
Five-membered metallacycles are typically reluctant to undergo endocyclic β-hydrogen elimination. The rhodium-catalyzed isomerization of 4-pentenals into 3-pentenals occurs through this elementary step and cleavage of two C-H bonds, as supported by deuterium-labeling studies. The reaction proceeds without decarbonylation, leads to trans olefins exclusively, and tolerates other olefins normally prone to isomerization. Endocyclic β-hydrogen elimination can also be controlled in an enantiodivergent reaction on a racemic mixture.
Easy access to esters with a benzylic quaternary carbon center from diallyl malonates by palladium-catalyzed decarboxylative allylation
Imao, Daisuke,Itoi, Akihiro,Yamazaki, Asako,Shirakura, Masamichi,Ohtoshi, Ryota,Ogata, Kenta,Ohmori, Yohki,Ohta, Tetsuo,Ito, Yoshihiko
, p. 1652 - 1658 (2007/10/03)
Diallyl 2-alkyl-2-arylmalonates underwent palladium-catalyzed decarboxylative allylation quickly under mild conditions. In contrast, no reaction took place with diallyl 2,2-dialkylmalonates under the same conditions. Electron-donating phosphine ligands were found to be vital for this reaction. Most of the solvents used did not affect the catalytic cycle. Catalysis in [bmim][BF4], a well-known ionic liquid, was inhibited as a result of formation of a hydrogen bond between a carboxylate anion and a [bmim] + cation; however, the reaction in [bdmim][BF4], in which the acidic proton of [bmim][BF4] was replaced with a methyl group, proceeded smoothly. The catalytic mechanism was investigated using a tetradeuterated substrate and an enzymatically synthesized enantio-enriched allyl methyl 2-methyl-2-phenylmalonate. Even the electron-deficient phosphite ligand was found to be active for catalysis of diallyl 2-methyl-2-(2- or 4-nitrophenyl)malonates.
Discovery of γ-lactam hydroxamic acids as selective inhibitors of tumor necrosis factor α converting enzyme: Design, synthesis, and structure-activity relationships
Duan, James J.-W.,Chen, Lihua,Wasserman, Zelda R.,Lu, Zhonghui,Liu, Rui-Qin,Covington, Maryanne B.,Qian, Mingxin,Hardman, Karl D.,Magolda, Ronald L.,Newton, Robert C.,Christ, David D.,Wexler, Ruth R.,Decicco, Carl P.
, p. 4954 - 4957 (2007/10/03)
New γ-lactam TACE inhibitors were designed from known MMP inhibitors. A homology model of TACE was built and examined to identify the S1′ site as the key area for TACE selectivity over MMPs. Rational exploration of the P1′-S1′ interactions resulted in the discovery of the 3,5-disubstituted benzyl ether as a TACE-selective P1′ group. Further optimization led to the discovery of IK682 as a selective and orally bioavailable TACE inhibitor.
