139469-06-0Relevant articles and documents
Olefination via Cu-Mediated Dehydroacylation of Unstrained Ketones
Dong, Guangbin,Xu, Yan,Zhou, Xukai
supporting information, p. 20042 - 20048 (2021/12/03)
The dehydroacylation of ketones to olefins is realized under mild conditions, which exhibits a unique reaction pathway involving aromatization-driven C-C cleavage to remove the acyl moiety, followed by Cu-mediated oxidative elimination to form an alkene between the α and β carbons. The newly adopted N′-methylpicolinohydrazonamide (MPHA) reagent is key to enable efficient cleavage of ketone C-C bonds at room temperature. Diverse alkyl- and aryl-substituted olefins, dienes, and special alkenes are generated with broad functional group tolerance. Strategic applications of this method are also demonstrated.
Substituted 9-Anthraldehydes from Dibenzocycloheptanol Epoxides via Acid-Catalyzed Epoxide Opening/Semipinacol Rearrangement
Phumjan, Tanawat,Songthammawat, Poramate,Jongcharoenkamol, Jira,Batsomboon, Paratchata,Ruchirawat, Somsak,Ploypradith, Poonsakdi
, p. 13322 - 13349 (2021/09/13)
Starting from benzaldehyde derivatives, the corresponding dibenzocycloheptenol could be prepared in five steps. Under both substrate (secondary vs tertiary alcohol and the substituents on the aromatic ring(s)) and condition control, the subsequent epoxidation and acid-catalyzed epoxide opening/semipinacol rearrangement/aromatization afforded the corresponding 9-anthraldehydes in good yields, up to 88% over two steps. The presence of the electron-withdrawing group(s) on the aromatic ring(s) suppressed the rate of the epoxidation while the subsequent semipinacol rearrangement step required heating; the presence of the electron-donating group(s), on the other hand, frequently led to the decomposition during the epoxidation. From the mechanistic studies, the semipinacol rearrangement of the epoxide could precede the ionization at the bisbenzylic position, yielding the aldehyde intermediate. The ensuing dehydrative aromatization led to the formation of 9-anthraldehyde. Conversely, nucleophilic addition to the aldehyde and dehydrative aromatization with concomitant loss of formic acid led to anthracene.
Sequential Addition of Amines to Nitrile and Carbon-Carbon Multiple Bond: A Route to 7-Amino-5 H-dibenzo[ c,e]azepines
Hu, Kun,Liu, Ruiting,Zhou, Xigeng
supporting information, p. 6946 - 6950 (2021/09/11)
A rare earth metal-catalyzed sequential inter- and intramolecular C-N bond formation of 2-nitrile-2′-alkenyl(alkynyl)biphenyls with amines has been developed, which provides a straightforward and efficient access to a range of new functional dibenzo[c,e]azepines. This represents the first examples of direct construction of seven-membered azaheterocycle from unsaturated nitriles and amines. Such transformations have the advantages of avoiding the use of additives, easily available starting materials, step- and high atom-economy, mild reaction conditions, and high selectivity.
Enantioselective Construction of Spiro Quaternary Carbon Stereocenters via Pd-Catalyzed Intramolecular α-Arylation
Wu, Ting,Kang, Xuehua,Bai, Heng,Xiong, Wenrui,Xu, Guangqing,Tang, Wenjun,Tang, Wenjun
supporting information, p. 4602 - 4607 (2020/06/29)
We herein report the development of a sterically hindered and electron-rich P-chiral monophosphorus biaryl ligand that has enabled a general and efficient enantioselective intramolecular α-arylation, providing access to a wide series of [4.4], [4.5], and [4.6]-spirocycles with chiral benzylic quaternary carbons in high yields with good to excellent enantioselectivities. A pronounced water effect on enantioselectivity is observed.
Stereoselective Convergent Synthesis of Tetrahydro-5 H-benzo[c]fluorene via Nine-Membered Ring-Closing Metathesis and Transannular Acid-Mediated Cyclization/Nucleophilic Addition
Lekky, Anek,Ruengsatra, Tanachote,Ruchirawat, Somsak,Ploypradith, Poonsakdi
, p. 5277 - 5291 (2019/05/10)
The diene methyl ethers or acetates, constructed from the Li-Br exchange/addition reactions of 2-vinylbenzaldehydes and 2-(but-3-en-1-yl)bromoarenes followed by etherification or acetylation of the corresponding alcohols, smoothly underwent the ring-closi
Direct synthesis of dialkylarylvinylsilane derivatives: Metathesis of dialkylaryl-iso-propenylsilane and its application to tetracyclic silacycle dye synthesis
Yoshioka, Shohei,Takehara, Tsunayoshi,Matsuzaki, Tsuyoshi,Suzuki, Takeyuki,Tsujino, Hirofumi,Uno, Tadayuki,Tsutsumi, Yasuo,Murai, Kenichi,Fujioka, Hiromichi,Arisawa, Mitsuhiro
supporting information, p. 14070 - 14073 (2019/11/25)
The metathesis of dialkylarylvinylsilane, which has not been accomplished to date, is achieved using dialkylaryl-iso-propenylsilane as a substrate. In addition, we discovered that the reason why the metathesis of a ruthenium carbene complex and dialkylarylvinylsilane is difficult is the formation of a carbide complex.
Intramolecular Acetyl Transfer to Olefins by Catalytic C?C Bond Activation of Unstrained Ketones
Rong, Zi-Qiang,Lim, Hee Nam,Dong, Guangbin
supporting information, p. 475 - 479 (2018/02/21)
A rhodium-catalyzed intramolecular acetyl-group transfer has been achieved through a “cut and sew” process. The challenge arises from the existence of different competitive pathways. Preliminary success has been achieved with unstrained enones that contain a biaryl linker. The use of an electron-rich N-heterocycilc carbene (NHC) ligand is effective to inhibit undesired β-hydrogen elimination. Various 9,10-dihydrophenanthrene derivatives can be prepared with excellent functional-group compatibility. The 13C-labelling study suggests that the reaction begins with cleavage of the unstrained C?C bond, followed by migratory insertion and reductive elimination.
The First Kilogram Synthesis of Beclabuvir, an HCV NS5B Polymerase Inhibitor
Bien, Jeffrey,Davulcu, Akin,Delmonte, Albert J.,Fraunhoffer, Kenneth J.,Gao, Zhinong,Hang, Chao,Hsiao, Yi,Hu, Wenhao,Katipally, Kishta,Littke, Adam,Pedro, Aghogho,Qiu, Yuping,Sandoval, Maria,Schild, Richard,Soltani, Michelle,Tedesco, Anthony,Vanyo, Dale,Vemishetti, Purushotham,Waltermire, Robert E.
, p. 1393 - 1408 (2018/09/06)
The process development and kilogram-scale synthesis of beclabuvir (BMS-791325, 1) is described. The convergent synthesis features the use of asymmetric catalysis to generate a chiral cyclopropane fragment and coupling with an indole fragment via an alkyl
Intramolecular Crossed [2+2] Photocycloaddition through Visible Light-Induced Energy Transfer
Zhao, Jiannan,Brosmer, Jonathan L.,Tang, Qingxuan,Yang, Zhongyue,Houk,Diaconescu, Paula L.,Kwon, Ohyun
supporting information, p. 9807 - 9810 (2017/08/03)
Herein, we present the intramolecular [2+2] cycloadditions of dienones promoted through sensitization, using a polypyridyl iridium(III) catalyst, to form bridged cyclobutanes. In contrast to previous examples of straight [2+2] cycloadditions, these efficient crossed additions were achieved under irradiation with visible light. The reactions delivered desired bridged benzobicycloheptanone products with excellent regioselectivity in high yields (up to 96%). This process is superior to previous syntheses of benzobicyclo[3.1.1]heptanones, which are readily converted to B-norbenzomorphan analogues of biological significance. Electrochemical, computational, and spectroscopic studies substantiated the mechanism of triplet energy transfer and explained the unusual regiocontrol.
Synthesis of Bridged Cyclopentane Derivatives by Catalytic Decarbonylative Cycloaddition of Cyclobutanones and Olefins
Zhou, Xuan,Ko, Haye Min,Dong, Guangbin
supporting information, p. 13867 - 13871 (2016/10/26)
Herein, we report an intramolecular rhodium-catalyzed decarbonylative coupling between cyclobutanones and alkenes that proceeds by C?C activation and provides a distinct approach to a diverse range of saturated bridged cyclopentane derivatives. In this reaction, cyclobutanones serve as cyclopropane surrogates, reacting in a formal (4+2?1) transformation. To demonstrate the efficacy of this method, it was applied in a concise synthesis of the antifungal drug Tolciclate.
