59142-64-2Relevant academic research and scientific papers
Divergent Access to Benzocycles through Copper-Catalyzed Borylative Cyclizations
Yoon, Wan Seok,Han, Jung Tae,Yun, Jaesook
supporting information, p. 4953 - 4959 (2021/09/14)
A copper-catalyzed chemodivergent approach to five- and six-membered benzocycles from dienyl arenes tethered with a ketone has been developed. Through proper choice of coordinating ligands and catalytic conditions, copper-catalyzed borylative cyclization of a single dienyl arene can be diverted to two different pathways, leading to indanols and dihydronaphthalenols with high stereoselectivity. The chiral bidentate bisphosphine ligand (S,S)-Ph-BPE was optimal for asymmetric copper-allyl addition to a tethered ketone via a boat-like transition state, whereas NHC ligands led to boro-allyl addition producing indanols with high diastereoselectivity. (Figure presented.).
Copper-catalyzed aerobic double functionalization of benzylic C(sp3)-H bonds for the synthesis of 3-hydroxyisoindolinones
Nozawa-Kumada, Kanako,Matsuzawa, Yuta,Ono, Kanako,Shigeno, Masanori,Kondo, Yoshinori
supporting information, p. 8604 - 8607 (2021/09/02)
A copper-catalyzed aerobic 3-hydroxyisoindolinone synthesis was developed via the benzylic double C(sp3)-H functionalization of 2-alkylbenzamides. In this reaction, molecular oxygen was used as both an oxidant for C(sp3)-H functionalization and an oxygen source. Our method can be extended to diverse benzylic C(sp3)-H bonds and shows excellent functional group tolerance. This journal is
Asymmetric Synthesis of 1,2-Dihydronaphthalene-1-ols via Copper-Catalyzed Intramolecular Reductive Cyclization
Acharyya, Ranjan Kumar,Kim, Soyoung,Park, Yeji,Han, Jung Tae,Yun, Jaesook
supporting information, p. 7897 - 7902 (2020/11/02)
We describe a copper-catalyzed intramolecular reductive cyclization of easily accessible benz-tethered 1,3-dienes containing a ketone moiety. This process provided biologically active 1,2-dihydronaphthalene-1-ol derivatives in good yields with excellent enantio- and diastereoselectivity. Mechanistic investigations using density functional theory revealed that (Z)- and (E)-allylcopper intermediates formed in situ from the diene and copper catalyst undergo isomerization and selective intramolecular allylation of the (E)-allylcopper form of the major product through a six-membered boatlike transition state. The resulting products were further transformed to fully saturated naphthalene-1-ols by reactions of the olefin moiety.
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
supporting information, 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(II)-catalyzed Intermolecular Cascade Cyclization of Methylenecyclopropanes with Aromatic Alkynes: Construction of Spirocyclic Compounds Containing Indene and 1,2-Dihydronaphthalene Moieties
Fang, Wei,Wei, Yin,Shi, Min
supporting information, (2019/05/22)
A palladium(II)-catalyzed intermolecular cascade cyclization of methylenecyclopropanes with aromatic alkynes is reported in this paper. The reaction involves a migratory insertion of alkyne, an intramolecular Heck-type reaction, and β-H elimination, providing a series of spirocyclic compounds containing indene and 1,2-dihydronaphthalene moieties in moderate to excellent yields upon heating.
Au-catalyzed biaryl coupling to generate 5- to 9-membered rings: Turnover-limiting reductive elimination versus π-complexation
Corrie, Tom J. A.,Ball, Liam T.,Russell, Christopher A.,Lloyd-Jones, Guy C.
supporting information, p. 245 - 254 (2017/05/29)
The intramolecular gold-catalyzed arylation of arenes by aryl-trimethylsilanes has been investigated from both mechanistic and preparative aspects. The reaction generates 5- to 9-membered rings, and of the 44 examples studied, 10 include a heteroatom (N, O). Tethering of the arene to the arylsilane provides not only a tool to probe the impact of the conformational flexibility of Ar-Au-Ar intermediates, via systematic modulation of the length of aryl-aryl linkage, but also the ability to arylate neutral and electron-poor arenes-substrates that do not react at all in the intermolecular process. Rendering the arylation intramolecular also results in phenomenologically simpler reaction kinetics, and overall these features have facilitated a detailed study of linear free energy relationships, kinetic isotope effects, and the first quantitative experimental data on the effects of aryl electron demand and conformational freedom on the rate of reductive elimination from diaryl-gold(III) species. The turnover-limiting step for the formation of a series of fluorene derivatives is sensitive to the reactivity of the arene and changes from reductive elimination to π-complexation for arenes bearing strongly electron-withdrawing substituents (σ > 0.43). Reductive elimination is accelerated by electron-donating substituents (ρ = -2.0) on one or both rings, with the individual σ-values being additive in nature. Longer and more flexible tethers between the two aryl rings result in faster reductive elimination from Ar-Au(X)-Ar and lead to the π-complexation of the arene by Ar-AuX2 becoming the turnover-limiting step.
Au-Catalyzed Biaryl Coupling to Generate 5- To 9-Membered Rings: Turnover-Limiting Reductive Elimination versus ?-Complexation
Ball, Liam T.,Corrie, Tom J. A.,Lloyd-Jones, Guy C.,Russell, Christopher A.
supporting information, p. 245 - 254 (2021/09/04)
The intramolecular gold-catalyzed arylation of arenes by aryl-trimethylsilanes has been investigated from both mechanistic and preparative aspects. The reaction generates 5- to 9-membered rings, and of the 44 examples studied, 10 include a heteroatom (N, O). Tethering of the arene to the arylsilane provides not only a tool to probe the impact of the conformational flexibility of Ar-Au-Ar intermediates, via systematic modulation of the length of aryl-aryl linkage, but also the ability to arylate neutral and electron-poor arenes - substrates that do not react at all in the intermolecular process. Rendering the arylation intramolecular also results in phenomenologically simpler reaction kinetics, and overall these features have facilitated a detailed study of linear free energy relationships, kinetic isotope effects, and the first quantitative experimental data on the effects of aryl electron demand and conformational freedom on the rate of reductive elimination from diaryl-gold(III) species. The turnover-limiting step for the formation of a series of fluorene derivatives is sensitive to the reactivity of the arene and changes from reductive elimination to ?-complexation for arenes bearing strongly electron-withdrawing substituents (σ > 0.43). Reductive elimination is accelerated by electron-donating substituents (ρ = -2.0) on one or both rings, with the individual σ-values being additive in nature. Longer and more flexible tethers between the two aryl rings result in faster reductive elimination from Ar-Au(X)-Ar and lead to the ?-complexation of the arene by Ar-AuX2 becoming the turnover-limiting step.
Diisobutylaluminum hydride-promoted cyclization of benzyl and phenylsilyl ethers bearing a 2-(trimethylsilyl)ethynyl group: syntheses of indenes and benzosiloles
Kinoshita, Hidenori,Fukumoto, Hiroki,Tohjima, Takayuki,Miura, Katsukiyo
supporting information, p. 3571 - 3574 (2016/07/18)
The reaction of o-[2-(trimethylsilyl)ethynyl]benzyl methyl ethers with diisobutylaluminum hydride (DIBAL-H) gave 2-(trimethylsilyl)indenes in good yields. This cyclization proceeds by regio- and stereoselective hydroalumination of the alkyne moiety followed by intramolecular nucleophilic substitution. o-[2-(Trimethylsilyl)ethynyl]phenylsilyl methyl ethers also underwent the DIBAL-H promoted-cyclization to be converted into 2-(trimethylsilyl)benzosiloles in good yields. This approach provides straightforward and efficient way to construct benzosiloles from readily available organosilanes.
Efficient palladium-catalyzed C(sp2)-H activation towards the synthesis of fluorenes
Song, Juan,Li, Yali,Sun, Wei,Yi, Chenglong,Wu, Hao,Wang, Haotian,Ding, Keran,Xiao, Kang,Liu, Chao
supporting information, p. 9030 - 9033 (2016/11/11)
A facile protocol for the synthesis of fluorene derivatives has been developed through palladium-catalyzed cyclization of 2′-halo-diarylmethanes via activation of arylic C-H bonds. The reactions occurred smoothly and allowed both electron-rich and electron-deficient substrates to convert into their corresponding fluorenes in good to excellent yields. Studies revealed that this Pd-catalyzed cyclization was also available for the substrates of 2′-chloro-diarylmethanes and no catalyst poisoning occurred for 2′-iodo-diphenylmethane.
Borylation of Olefin C-H Bond via Aryl to Vinyl Palladium 1,4-Migration
Hu, Tian-Jiao,Zhang, Ge,Chen, Ya-Heng,Feng, Chen-Guo,Lin, Guo-Qiang
supporting information, p. 2897 - 2900 (2016/03/19)
The aryl to vinyl palladium 1,4-migration was realized for the first time. The generated alkenyl palladium species was trapped by diboron reagents under Miyaura borylation conditions, providing a new method to synthesize β,β-disubstituted vinylboronates. The excellent regioselectivity and broad substrate scope were observed for this novel transformation.
