- Palladium-Catalyzed Tandem Hydrocarbonylative Lactamization and Cycloaddition Reaction for the Construction of Bridged Polycyclic Lactams
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The intramolecular hydroaminocarbonylation of alkenes is a compelling tool to rapidly access lactam, a privileged motif ubiquitous in natural products, pharmaceuticals, and agrochemicals. However, selective carbonylation to bridged polycyclic lactams with a lactam nitrogen at a bridgehead position is less explored. We herein report a modular palladium-catalyzed approach to perform a tandem hydrocarbonylative lactamization/Diels-Alder cycloaddition reaction with 2-vinyl aryl aldimines, alkenes, and CO, which offers convenient access to furnish the bridged polycyclic lactams in high yields with high selectivities.
- Xu, Pengcheng,Qian, Bo,Hu, Bin,Huang, Hanmin
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supporting information
p. 147 - 151
(2022/01/04)
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- Substituted 9-Anthraldehydes from Dibenzocycloheptanol Epoxides via Acid-Catalyzed Epoxide Opening/Semipinacol Rearrangement
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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.
- Phumjan, Tanawat,Songthammawat, Poramate,Jongcharoenkamol, Jira,Batsomboon, Paratchata,Ruchirawat, Somsak,Ploypradith, Poonsakdi
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p. 13322 - 13349
(2021/09/13)
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- A metal-free method for the facile synthesis of indanonesviathe intramolecular hydroacylation of 2-vinylbenzaldehyde
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A facile method for the synthesis of indanones was developed under metal- and additive-free conditions, whereinl-proline served as an efficient and environmentally benign catalyst. Compared with previously synthesized indanones, synthesis by the transition-metal-catalyzed intramolecular hydroacylation of 2-vinylbenzaldehyde provided a more green synthetic pathway to indanone scaffolds with good to excellent yields. More importantly, it could be used to synthsize the anti-AD drug donepezil.
- He, Guoxue,Ma, Jinyu,Zhou, Jianhui,Li, Chunpu,Liu, Hong,Zhou, Yu
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supporting information
p. 1036 - 1040
(2021/02/09)
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- Enantioselective Remote C(sp3)-H Cyanation via Dual Photoredox and Copper Catalysis
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The remote C(sp3)-H cyanation of carboxamides has been described by merging photoredox and copper catalysis in a site-selective and enantiocontrolled manner. The protocol is the integration of photoinduced and nitrogen-centered radical-mediated intermolecular hydrogen atom transfer with chiral copper-complex-catalyzed radical cyanation. This strategy gives enantio-enriched cyanated amides in high yields.
- Chen, Hui,Jin, Weiwei,Yu, Shouyun
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supporting information
p. 5910 - 5914
(2020/08/12)
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- Carbonylative cycloaddition between two different alkenes enabled by reactive directing groups: Expedited construction of bridged polycyclic skeletons
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A novel palladium-catalyzed highly selective hydrocarbonylative cycloaddition reaction with two different alkenes in the presence of CO enabled by a reactive directing-group is developed, which offers efficient and convenient access to lactone-containing bridged polycyclic compounds in high yield with high chemo- and stereoselectivities.
- Gao, Bingjian,Zou, Suchen,Yang, Guoqing,Ding, Yongzheng,Huang, Hanmin
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supporting information
p. 12198 - 12201
(2020/10/26)
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- Inter- and intramolecular hydroacylation of alkenes employing a bifunctional catalyst system
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Based on a conceptually innovative bifunctional P,N ligand, an efficient protocol for the rhodium-catalyzed inter- and intramolecular hydroacylation of alkenes has been developed.
- Vautravers, Nicolas R.,Regent, Damien D.,Breit, Bernhard
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supporting information; experimental part
p. 6635 - 6637
(2011/06/27)
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- Investigation of a domino heck reaction for the rapid synthesis of bicyclic natural products
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(Figure Presented) Unexpected Heck: During efforts toward the synthesis of FR900482, an unexpected domino Heck product was isolated (see scheme). Although this pathway was ultimately not productive for the aforementioned natural product synthesis, efforts were made to extend the methodology to the synthesis of amurensinine. To our knowledge this domino reaction was the first such tandem Heck-alkylation pathway in the presence of a geometrically favorable β-hydrogen elimination.
- Trost, Barry M.,O'Boyle, Brendan M.,Hund, Daniel
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supporting information; experimental part
p. 9772 - 9776
(2010/10/19)
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- An efficient method for construction of tetrahydroisoquinoline skeleton via double cyclization process using ortho-vinylbenzaldehydes and amino alcohols: application to the synthesis of (S)-cryptostyline II
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Thermal double cyclization reaction using ortho-vinylbenzaldehyde and 3-aminopropanols proceeded smoothly to give isoquinoline derivatives via 6π-azaelectrocyclization pathway. The method was applied to the efficient synthesis of (S)-cryptostyline II.
- Umetsu, Kazuteru,Asao, Naoki
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p. 2722 - 2725
(2008/09/18)
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- Acids direct 2-styrylcyclobutanone into two distinctly different reaction pathways
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(Chemical Equation Presented) Two structurally distinct carbocycles were selectively obtained by the reactions of 2-(o-styryl)cyclobutanones promoted by ytterbium salts. Treatment of the cyclobutanones with YbCl3 in 1,4-dioxane at 100°C afforde
- Murakami, Masahiro,Kadowaki, Sho,Fujimoto, Atsushi,Ishibashi, Mitsuru,Matsuda, Takanori
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p. 2059 - 2061
(2007/10/03)
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- THE ALTERNATIVE SYNTHESIS OF ISOQUINOLINE NUCLEUS USING THE THERMAL ELECTROCYCLIC REACTION OF 1-AZAHEXA-1,3,5-TRIENE SYSTEM
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The thermal electrocyclic reaction of 2-alkenylbenzaldoximes or their derivatives having conjugated 1-azahexatriene system in o-dichlorobenzene gave isoquinolines in moderate to good yields except the reaction of unsubstituted 2-alkenylbenzaldoxime and its oxime ethers.
- Hibino, Satoshi,Sugino, Eiichi,Adachi, Yukiko,Nomi, Kazuhiko,Sato, Kohichi,Fukumoto, Keiichiro
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p. 275 - 282
(2007/10/02)
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