1985-32-6Relevant academic research and scientific papers
AuBr3-catalyzed [4 + 2] benzannulation between an enynal unit and enol
Asao, Naoki,Aikawa, Haruo,Yamamoto, Yoshinori
, p. 7458 - 7459 (2004)
The reaction of enynals 1, including o-alkynylbenzaldehydes, and carbonyl compounds 2 in the presence of a catalytic amount of AuBr3 in 1,4-dioxane at 100 °C gave the functionalized aromatic compounds 3 in high yields. The AuBr3-catalyzed formal [4 + 2] benzannulation proceeds most probably through the coordination of the triple bond of 1 to AuBr3, the formation of a pyrylium auric ate complex via the nucleophilic addition of the carbonyl oxygen atom, the reverse electron demand-type Diels-Alder addition of the enols, derived from 2, to the auric ate complex, and subsequent dehydration and bond rearrangement. Similarly, the AuBr3-catalyzed reactions of 1 with acetal compounds afforded the corresponding aromatic compounds in good yields. Copyright
Lewis acid-catalyzed [4 + 2] benzannulation between enynal units and enols or enol ethers: Novel synthetic tools for polysubstituted aromatic compounds including indole and benzofuran derivatives
Asao, Naoki,Aikawa, Haruo
, p. 5249 - 5253 (2006)
The reaction of enynals 1, including o-(alkynyl)benzaldehydes, and carbonyl compounds 2, such as aldehydes and ketones, in the presence of a catalytic amount of AuBr3 in 1,4-dioxane at 100 °C gave the functionalized aromatic compounds 3 in high yields. Similarly, the AuBr3-catalyzed reactions of 1 with acetal compounds 5 afforded the corresponding aromatic compounds 3 in good yields. On the other hand, when the reaction was carried out in the presence of a catalytic amount of Cu(NTf2)2 and 1 equiv of H2O in (CH2Cl)2 at 100 °C, the decarbonylated naphthalene products 4 were obtained selectively over 3. Benzofused heteroaromatic compounds, such as indole derivatives 13 and benzofuran derivatives 15, were also synthesized by using the present benzannulation methodology.
Divergent Synthesis of Highly Substituted Pyridines and Benzenes from Dienals, Alkynes, and Sulfonyl Azides
Luo, Han,Li, You,Du, Luan,Xin, Xiaolan,Wang, Tao,Han, Jingpeng,Tian, Yi,Li, Baosheng
supporting information, p. 7883 - 7887 (2021/10/20)
Divergent synthesis is extremely important for the highly efficient preparation of structurally diverse target molecules. Herein, we describe a multicomponent cascade reaction, which allows access to highly substituted pyridines and benzenes by combining four individual steps in a one-pot manner from the same set of readily available starting materials. The azepine intermediates were first used as the precursors for 6π-electrocyclization to construct highly substituted pyridines and benzenes in a tunable manner.
New Nickel-Based Catalytic System with Pincer Pyrrole-Functionalized N-Heterocyclic Carbene as Ligand for Suzuki-Miyaura Cross-Coupling Reactions
Guo, Zhifo,Lei, Xiangyang
supporting information, (2021/09/11)
A new catalytic system with Ni(NO3)2·6H2O as the catalyst and a pincer pyrrole-functionalized N-heterocyclic carbene as the ligand was employed in the Suzuki-Miyaura cross-coupling reactions of aryl iodides with arylboronic acids. With 5 mol% catalyst, the catalytic reactions proceeded at 160 °C, giving coupling products in isolated yields of up to 94% in short reaction times (1-4 h). The system worked efficiently with aryl iodides bearing electron-donating or electron-withdrawing groups and arylboronic acids with electron-donating groups. Steric effects were observed for both aryl iodides and arylboronic acids. It is proposed that the reactions underwent a Ni(I)/Ni(III) catalytic cycle.
Chiral electron-rich PNP ligand with a phospholane motif: Structural features and application in asymmetric hydrogenation
Wang, Heng,Zhang, Yao,Yang, Tilong,Guo, Xiaochong,Gong, Quan,Wen, Jialin,Zhang, Xumu
, p. 8796 - 8801 (2020/11/13)
Despite the remarkable reactivity that was achieved by a series of transition-metal catalysts with a PNP type ligand, the electron-rich chiral PNP ligands have still been rarely reported because of the difficulties in synthesis and the nature of air-sensitivity. Herein, we report a novel chiral PNP ligand (Heng-PNP) with both a rigid backbone and a bulky tert-butyl group on the phospholane motif. We successfully obtained its divalent iron complex. The chiral environment of its Ir(III) complex was also discussed with quadrant analysis. This tridentate ligand was applied in iridium-catalyzed asymmetric hydrogenation of challenging diaryl ketones: up to 98% ee and 500 TON are achieved. Computational study showed that the twist of conjugate aryl group in the substrate (induced by the special chiral pocket of Ir/Heng-PNP complex) leads to the energy difference in the enantiodetermining step.
Palladium-Catalyzed Amide N-C Hiyama Cross-Coupling: Synthesis of Ketones
Idris, Muhammad Aliyu,Lee, Sunwoo
supporting information, p. 9190 - 9195 (2020/11/18)
N-Acylglutarimides and arylsiloxanes reacted in the presence of Pd(OAc)2/PCy3, Et3N·3HF, and LiOAc to provide the corresponding arylketones in good yields. Aryl-, vinyl-, and alkyl-substituted N-acylglutarimides showed good activity in the coupling reactions of arylsiloxanes. The reaction had a broad substrate scope and showed good functional group tolerance. N-Benzoylsuccinimide and N-protected N-phenylbenzamides showed good activities in coupling reactions with phenylsiloxane. The employment of CuF2 as an activor afforded the decarbonylative products at 160 °C.
6-Arylphenanthridines from Aryl o-Biaryl Ketones with 1,1,1,3,3,3-Hexamethyldisilazane and Molecular Iodine
Kobayashi, Eiji,Kishi, Atsushi,Togo, Hideo
, p. 7335 - 7347 (2019/11/22)
Warming treatment of aryl o-biaryl ketones with 1,1,1,3,3,3-hexamethyldisilazane in the presence of Sc(OTf)3 in toluene, followed by the reaction with molecular iodine and K2CO3 in a mixture of THF and methanol at 60 °C gave the corresponding 6-arylphenanthridines in good to moderate yields. The present reaction is a one-pot method for the preparation of 6-arylphenanthridines from aryl o-biaryl ketones through the cyclization of imino-nitrogen-centered radicals that were generated from N-iodo aryl o-biaryl ketimines formed from the reaction of aryl biaryl ketimines with molecular iodine.
Ruthenium(0)-Catalyzed Cross-Coupling of Anilines with Organoboranes by Selective Carbon-Nitrogen Cleavage
Zhao, Qun,Zhang, Jin,Szostak, Michal
, p. 8171 - 8177 (2019/08/22)
Selective activation of neutral carbon-nitrogen bonds is of great synthetic importance, because amines are among the most prevalent motifs across organic and bioactive molecules. Herein, we report the Ru(0)-catalyzed selective cleavage of neutral C(aryl)-N bonds in generic aniline derivatives enabled by a combination of Ru3(CO)12 and an imino auxiliary. These mild conditions provide a direct route to high-value biaryl ketones and biaryl aldehydes after facile in situ hydrolysis. A broad range of organoboranes and anilines can be coupled with high C-N cleavage selectivity. Most crucially, the reaction achieves exquisite selectivity for activation of C(aryl)-N bonds in the presence of typically more kinetically favorable C(aryl)-H bonds. The method provides a strategy for the construction of functionalized terphenyls by exploiting orthogonal properties of the Ru(0) catalyst system and traceless nucleophilic properties of anilines.
AMINE COMPOUND AND ORGANIC ELECTROLUMINESCENCE DEVICE INCLUDING THE SAME
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Paragraph 0102; 0103, (2018/10/21)
An amine compound and an organic electroluminescence device including the same are provided. The amine compound according to an embodiment of the inventive concept is represented by Formula 1.
Palladium-catalyzed Suzuki-Miyaura coupling of aryl esters
Halima, Taoufik Ben,Zhang, Wanying,Yalaoui, Imane,Hong, Xin,Yang, Yun-Fang,Houk, Kendall N.,Newman, Stephen G.
supporting information, p. 1311 - 1318 (2017/05/16)
The Suzuki-Miyaura coupling is among the most important C-C bond-forming reactions available due to its reliability, chemoselectivity, and diversity. Aryl halides and pseudohalides such as iodides, bromides, and triflates are traditionally used as the electrophilic coupling partner. The expansion of the reaction scope to nontraditional electrophiles is an ongoing challenge to enable an even greater number of useful products to be made from simple starting materials. Herein, we present how an NHC-based Pd catalyst can enable Suzuki-Miyaura coupling where the C(acyl)-0 bond of aryl esters takes on the role of electrophile, allowing the synthesis of various ketone-containing products. This contrasts known reactions of similar esters that provide biaryls via nickel catalysis. The underlying cause of this mechanistic divergence is investigated by DFT calculations, and the robustness of esters compared to more electrophilic acylative coupling partners is analyzed.
