- Selective synthesis of alkynylated isoquinolines and biisoquinolines via RhIII catalyzed C-H activation/1,3-diyne strategy
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Described herein is a convenient and highly selective synthesis of alkynylated isoquinolines and biisoquinolines from various aryl ketone O-pivaloyloxime derivatives and 1,3-diynes via rhodium-catalyzed C-H bond activation. In this transformations, alkynylated isoquinolines, 3,4′- and 3,3′-biisoquinolines could be obtained respectively through changing the reaction conditions. Mechanistic investigation revealed that the C-H activation of aryl ketone O-pivaloyloxime was the key step to this reaction.
- Feng, Ruokun,Ning, Hanqi,Su, Han,Gao, Yuan,Yin, Haotian,Wang, Yudan,Yang, Zhen,Qi, Chenze
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- Rhodium-Catalyzed One-Pot Access to N-Polycyclic Aromatic Hydrocarbons from Aryl Ketones through Triple C-H Bond Activations
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A Rh-catalyzed pot and step economic synthesis of aza-polycyclic aromatic hydrocarbons (N-PAHs) from readily available aryl ketones and alkynes has been disclosed. Additionally, a novel synthetic application of the well-known aminating reagent hydroxylamine-O-sulfonic acid (HOSA) has been explored as an in situ redox-neutral directing group for the formation of N-PAHs via isoquinoline. Multiple bond formation in a single operation through a cascade of triple C-H bond activations is the beauty of this protocol. The challenging annulations of two different alkynes in a regioselective fashion have been demonstrated effectively. Mechanistic studies reveal that 3,4-diphenyl-1-methylisoquinoline is an active intermediate for this one-pot transformation.
- Biswal, Pragati,Banjare, Shyam Kumar,Pati, Bedadyuti Vedvyas,Mohanty, Smruti Ranjan,Ravikumar, Ponneri Chandrababu
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p. 1108 - 1117
(2021/01/09)
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- Rh(III)-catalyzed synthesis of isoquinolines using the N-Cl bond of N-chloroimines as an internal oxidant
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The Rh(III)-catalyzed coupling of N-chloroimines with alkynes for the efficient synthesis of isoquinolines is reported. This represents the first use of the N-Cl bond of N-chloroimines as an internal oxidant for construction of the isoquinoline skeleton. The synthesis features atom and step economy, a green solvent (EtOH), mild reaction conditions, and a broad substrate scope.
- Chu, Benfa,Fang, Lili,Guo, Shan,Qi, Bing,Shi, Pengfei,Wang, Qi,Zhu, Jin
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- Hydroxylamine-O-Sulfonic Acid (HOSA) as a Redox-Neutral Directing Group: Rhodium Catalyzed, Additive Free, One-Pot Synthesis of Isoquinolines from Arylketones
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A new application of hydroxylamine-O-sulfonic acid (HOSA) has been discovered whereby aromatic ketones react with HOSA and alkynes to form isoquinolines in the presence of a RhIII catalyst. This C–H/N–O annulation methodology gives excellent yields even without any silver additive, acid/base or metal oxidant. This is the first report wherein a directing group is simultaneously forming in situ, acting as acid additive, and also as an internal oxidant.
- Biswal, Pragati,Pati, Bedadyuti Vedvyas,Chebolu, Rajesh,Ghosh, Asit,Ravikumar
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p. 1006 - 1014
(2020/02/15)
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- Cp*Co(iii)-catalyzed annulation of azines by C-H/N-N bond activation for the synthesis of isoquinolines
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Herein, an efficient, atom economic and external oxidant free approach has been disclosed for the synthesis of isoquinolines. Azines were employed for annulation reactions with alkynes via sequential C-H/N-N bond activation using an air-stable cobalt catalyst. The method takes advantage of the incorporation of both the nitrogen atoms of azines into the desired isoquinoline products, offering the highest atom economy. In addition, the developed protocol works under external oxidant as well as silver salt free conditions. Furthermore, the established methodology features a relatively broad substrate scope with high product yields and scalability up to the gram level.
- Deshmukh, Dewal S.,Yadav, Prashant A.,Bhanage, Bhalchandra M.
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p. 3489 - 3496
(2019/04/14)
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- Rapid and Atom Economic Synthesis of Isoquinolines and Isoquinolinones by C–H/N–N Activation Using a Homogeneous Recyclable Ruthenium Catalyst in PEG Media
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Herein, we report an atom-efficient, rapid, green, and sustainable approach to synthesize isoquinolines and isoquinolinones using a homogeneous recyclable ruthenium catalyst in PEG Media assisted by microwave energy. Dibenzoylhydrazine was used for C–H/N–N activation reactions for the first time in combination with ketazine as oxidizing directing groups for annulation reactions with internal alkynes. The developed protocol is environmentally benign due to significantly shortened times with an easy extraction method, higher atom economy, external oxidant and silver or antimony salt free conditions, applicability to a gram scale synthesis, use of biodegradable solvent and wide substrate scope with higher product yields. Moreover, it is worth noting that the established methodology allowed reuse of the catalytic system for up to five successive runs with minimal loss in activity.
- Deshmukh, Dewal S.,Gangwar, Neha,Bhanage, Bhalchandra M.
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p. 2919 - 2927
(2019/05/10)
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- Cp*Co(III) catalyzed annulation of N-Cbz hydrazones for the redox-neutral synthesis of isoquinolines via C–H/N–N bond activation
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A new cascade oxidative cyclization reaction of N-Cbz hydrazones with internal alkynes has been explored for the preparation of isoquinoline derivatives using Cp*CoIII-catalyst through C–H and N–N bond functionalization. N-Cbz hydrazones are ra
- Subhedar, Dnyaneshwar D.,Deshmukh, Dewal S.,Bhanage, Bhalchandra M.
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p. 3121 - 3130
(2019/08/30)
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- Ruthenium-Catalyzed Annulation of N -Cbz Hydrazones via C-H/N-N Bond Activation for the Rapid Synthesis of Isoquinolines
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In this work, N -Cbz hydrazone has been employed as a rarely explored directing group for the synthesis of isoquinolines by annulation with internal alkynes via C-H/N-N activation using Ru catalyst. Additive as well as external oxidant-free rapid protocol
- Bhanage, Bhalchandra M.,Deshmukh, Dewal S.
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p. 2506 - 2514
(2019/06/08)
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- N-Tosylhydrazone directed annulation via C-H/N-N bond activation in Ru(ii)/PEG-400 as homogeneous recyclable catalytic system: a green synthesis of isoquinolines
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A green and sustainable methodology for the synthesis of isoquinolines using Ru(ii)/PEG-400 as a homogeneous recyclable catalytic system has been demonstrated. N-Tosylhydrazone, a rarely explored directing group, has been successfully employed for an annu
- Deshmukh, Dewal S.,Bhanage, Bhalchandra M.
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p. 4864 - 4873
(2018/07/15)
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- Easy Access to 1-Amino and 1-Carbon Substituted Isoquinolines via Cobalt-Catalyzed C - H/N - O Bond Activation
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A green atom-economical method for the synthesis of highly functionalized 1-amino and 1-carbon substituted isoquinolines from the reaction of N′-hydroxybenzimidamides and aryl ketoximes, respectively, with alkynes via pentamethylcyclopentadienylcobalt(III)-catalyzed C - H/N - O bond activation is described. The external oxidant-free annulation reaction uses the =NOH moiety in N′-hydroxybenzimidamides or N-aromatic ketone oximes as the directing group and internal oxidant. This first row transition metal-catalyzed annulation serves as an efficient alternative for the synthesis of isoquinolines, as water is the only by-product and expensive noble metals such as rhodium(III), iridium(III), palladium(II), and ruthenium(II) are not required. The reaction proceeds via C - H activation, alkyne insertion, reductive elimination, and N - O activation.
- Muralirajan, Krishnamoorthy,Kuppusamy, Ramajayam,Prakash, Sekar,Cheng, Chien-Hong
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p. 774 - 783
(2016/03/09)
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- Cobalt(III)-Catalyzed Dehydrative [4+2] Annulation of Oxime with Alkyne by C-H and N-OH Activation
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Efficient, scalable cobalt-catalyzed redox-neutral [4+2] annulation of readily available oximes and alkyne is reported. The developed synthetic methodology is widely applicable and tolerates various functional groups including heterocycles. A stable CpCoIII neutral complex is employed as the catalyst for this redox-neutral [4+2] annulation reaction, which progresses smoothly by way of a reversible cyclometallation without any external oxidizing agent, and produces only water as the side product.
- Sen, Malay,Kalsi, Deepti,Sundararaju, Basker
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p. 15529 - 15533
(2015/11/03)
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- Rhodium(III)-catalyzed one-pot access to isoquinolines and heterocycle-fused pyridines in aqueous medium through C-H cleavage
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An efficient RhIII-catalyzed ortho-C-H bond activation for the synthesis of substituted isoquinolines and heterocycle-fused pyridines in aqueous medium has been developed. This method involves the in situ generation of ketimines from ketones an
- Zhang, Jitan,Qian, Hongsheng,Liu, Zhanxiang,Xiong, Chunhua,Zhang, Yuhong
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p. 8110 - 8118
(2015/02/02)
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- C-H activation guided by aromatic N-H ketimines: Synthesis of functionalized isoquinolines using benzyl azides and alkynes
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Aromatic N-H ketimines were in situ generated from various benzylic azides by ruthenium catalysis for the subsequent Rh-catalyzed annulation reaction with alkynes to give the corresponding isoquinolines. In contrast to conventional synthetic methods for aromatic N-H ketimines, our protocol works under mild and neutral conditions, which enabled the synthesis of isoquinolines having various functionalities such as carbonyl, ester, alkenyl, and ether groups. In addition, the imidates generated from α-azido ethers were successfully used for the synthesis of 1-alkoxyisoquinolines.
- Gupta, Sreya,Han, Junghoon,Kim, Yongjin,Lee, Soon W.,Rhee, Young Ho,Park, Jaiwook
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p. 9094 - 9103
(2014/12/11)
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- Synthesis of isoquinolines via Rh(III)-catalyzed C-H activation using hydrazone as a new oxidizing directing group
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An efficient and mechanistically interesting method for the synthesis of highly substituted isoquinolines by a Rh(III)-catalyzed hydrazone directed ortho C-H bond activation and annulation without an external oxidant is described. This reaction is accomplished via a C-C and C-N bond formation along with N-N bond cleavage.
- Chuang, Sheng-Chieh,Gandeepan, Parthasarathy,Cheng, Chien-Hong
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p. 5750 - 5753
(2013/12/04)
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- Synthesis of isoquinolines and heterocycle-fused pyridines via three-component cascade reaction of aryl ketones, hydroxylamine, and alkynes
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An efficient one-pot synthesis of isoquinolines and heterocycle-fused pyridines by three-component reaction of aryl ketones, hydroxylamine, and alkynes is developed. The reaction involves condensation of aryl ketones and hydroxylamine, rhodium(III)-cataly
- Zheng, Liyao,Ju, Jia,Bin, Yunhui,Hua, Ruimao
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experimental part
p. 5794 - 5800
(2012/07/30)
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- Nickel-catalyzed cyclization of ortho-iodoketoximes and ortho-iodoketimines with alkynes: Synthesis of highly substituted isoquinolines and isoquinolinium salts
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A convenient method for the synthesis of highly substituted isoquinolines and isoquinolinium salts by the nickel-catalyzed cyclization of ortho-haloketoximes and -ketimines, respectively, with alkynes is described. The reaction of ortho-haloketoximes and various alkynes in the presence of [Ni(PPh3)2Br2] and zinc powder in a mixture of acetonitrile and tetrahydrofuran at 80 °C for 15 hours gave 1,3,4-trisubstituted isoquinoline products in moderate to excellent yields and high regioselectivity. The corresponding isoquinoline N-oxide was found to be the intermediate in the cyclization reaction pathway. In contrast, the reaction of ortho-haloketimines and alkynes under similar catalytic conditions in tetrahydrofuran at 70 °C for two hours gave 1,2,3,4-tetrasubstituted isoquinolinium salts in good to excellent yields. In the nickel of time: ortho-Haloketoximes and -ketimines undergo [4+2] cyclization reactions with alkynes, catalyzed by nickel complexes to give highly substituted isoquinolines and isoquinolinium salts, respectively, in good to excellent yields (see scheme).
- Shih, Wei-Chun,Teng, Chu-Chun,Parthasarathy, Kanniyappan,Cheng, Chien-Hong
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p. 306 - 313
(2012/05/05)
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- Cationic ruthenium catalysts for alkyne annulations with oximes by C-H/N-O functionalizations
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Cationic ruthenium(II) complexes enabled efficient redox-neutral annulations of alkynes with readily available oximes. The catalytic dehydrative C-H/N-O bond functionalization proved to be broadly applicable and was shown to proceed through a reversible cyclometalation.
- Kornhaass, Christoph,Li, Jie,Ackermann, Lutz
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p. 9190 - 9198,9
(2012/12/11)
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- Pyridine synthesis from oximes and alkynes via rhodium(iii) catalysis: Cp* and Cpt provide complementary selectivity
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The synthesis of pyridines from readily available α,β- unsaturated oximes and alkynes under mild conditions and low temperatures using Rh(iii) catalysis has been developed. It was found that the use of sterically different ligands allows for complementary selectivities to be achieved.
- Hyster, Todd K.,Rovis, Tomislav
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supporting information; experimental part
p. 11846 - 11848
(2011/12/02)
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- Easy access to isoquinolines and tetrahydroquinolines from ketoximes and alkynes via rhodium-catalyzed C-H bond activation
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(Chemical Equation Presented) Described herein is a convenient and highly regioselective synthesis of substituted isoquinoline derivatives from various aromatic ketoximes and alkynes via a one-pot, rhodium-catalyzed C-H bond activation. In addition, tetra
- Parthasarathy, Kanniyappan,Cheng, Chien-Hong
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supporting information; experimental part
p. 9359 - 9364
(2010/03/04)
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