Synthesis of 5- and 6-Azaindoles by Sequential Site-Selective Palladium-Catalyzed C–C and C–N Coupling Reactions

Synlett ◽  
2020 ◽  
Vol 31 (13) ◽  
pp. 1308-1312
Author(s):  
Tuan Thanh Dang ◽  
Peter Langer ◽  
Nguyen Thi Son ◽  
Tuan Anh Nguyen Tien ◽  
Marian Blanco Ponce ◽  
...  
Keyword(s):  
Coupling Reaction ◽  
The Other ◽  
Sonogashira Reaction ◽  
Coupling Reactions ◽  
Other Hand ◽  
Sequential Procedures ◽  
Palladium Catalyzed ◽  
A Site ◽  
Site Selective

Two-step sequential procedures for the Pd-catalyzed synthesis of 5- and 6-azaindoles are reported. The reactions proceed in very good yields. 6-Azaindoles are formed through site-selective Pd-catalyzed Sonogashira reaction of 3,4-dibromopyridine with alkynes, followed by a Pd-catalyzed tandem C–N coupling and cyclization with amines. On the other hand, 5-azaindoles are obtained by a site-selective Pd-catalyzed C–N coupling reaction of 3,4-dibromopyridine with amines, followed by C–C coupling and cyclization with alkynes.

Palladium Catalyzed Synthesis of Phenylquinoxaline-Alkyne Derivatives via Sonogashira Cross Coupling Reaction

2021 ◽  
Vol 43 (1) ◽  
pp. 95-95
Author(s):  
Rifhat Bibi Rifhat Bibi ◽  
Muhammad Yaseen Muhammad Yaseen ◽  
Haseen Ahmad Haseen Ahmad ◽  
Ismat Ullah Khan Ismat Ullah Khan ◽  
Shaista Parveen Shaista Parveen ◽  
...  
Keyword(s):  
Coupling Reaction ◽  
Cross Coupling ◽  
Sonogashira Reaction ◽  
Terminal Alkynes ◽  
Vinyl Halides ◽  
Sonogashira Coupling Reaction ◽  
Quinoxaline Derivatives ◽  
Palladium Catalyzed ◽  
High Yields ◽  
Alkyne Derivatives

Transition metals mediated cross coupling methodologies provide an extremely powerful versatile pathway in organic syntheses undoubtedly, a facile route for syntheses and derivatization of biologically important heterocycles from easily available precursors. Sonogashira coupling reaction, a leading method to Csp-Csp2 bond formation is one of the most important and rapid pathways to couple aryl/vinyl halides with terminal alkynes. Current research study deals with the synthesis of alkyne substituted quinoxaline derivatives. The quinoxalines class of aromatic heterocycles exhibits a wide variety of important biological potencies. Palladium catalyzed cross coupling process provided an effective synthetic practice for the synthesis of alkyne derivatives of quinoxaline. Vareity of terminal alkynes were coupled with 2-(4-bromophenyl)quinoxaline under optimized conditions for Sonogashira reaction, affording alkyne substituted quinoxaline derivatives in high yields. The optimized reaction conditions for coupling of range of terminal alkyne with quinoxaline basic core render this process significant for designing of medicinally interesting precursors.

Regiospecific Palladium-Catalyzed Cross-Coupling Reactions Using the Operational Equivalent of 1,3-Dilithiopropyne

Synthesis ◽  
2020 ◽  
Vol 52 (16) ◽  
pp. 2387-2394 ◽  
Author(s):  
Jorge A. Cabezas ◽  
Natasha Ferllini
Keyword(s):  
Coupling Reaction ◽  
Cross Coupling ◽  
Coupling Reactions ◽  
Terminal Alkyne ◽  
Copper Iodide ◽  
Reaction Conditions ◽  
Cross Coupling Reactions ◽  
Cross Coupling Reaction ◽  
Palladium Catalyzed ◽  
High Yields

A regiospecific palladium-catalyzed cross-coupling reaction using the operational equivalent of the dianion 1,3-dilithiopropyne, with aromatic iodides is reported. This reaction gives high yields of 1-propyn-1-yl-benzenes and 2-(propyn-1-yl)thiophenes in the presence of catalytic amounts of palladium(0) or (II) and stoichiometric amounts of copper iodide. No terminal alkyne or allene isomers were detected. Reaction conditions were very mild and several functional groups were tolerated.

scholarly journals Palladium-catalyzed Suzuki-Miyaura coupling of thioureas or thioamides

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Shaoyu Mai ◽  
Wendong Li ◽  
Xue Li ◽  
Yingwei Zhao ◽  
Qiuling Song
Keyword(s):  
Silver Salt ◽  
Coupling Reaction ◽  
Coupling Reactions ◽  
Mechanistic Studies ◽  
Aromatic Rings ◽  
Cross Coupling Reactions ◽  
Broad Array ◽  
Palladium Catalyzed

AbstractCross-coupling reactions involving metal carbene intermediates play an increasingly important role in C–C bond formation. Expanding the carbene precursors to a broader range of starting materials and more diverse products is an ongoing challenge in synthetic organic chemistry. Herein, we report a Suzuki-Miyaura coupling reaction of in situ-generated Pd–carbene complexes via desulfurization of thioureas or thioamides. This strategy enables the preparation of a broad array of substituted amidinium salts and unsymmetrical diaryl ketones. The reaction is readily scalable, compatible with bromo groups on aromatic rings, tolerant to moisture and air and has a broad substrate scope. Furthermore, a single crystal structure of Pd-diaminocarbene complex is obtained and proven to be the key intermediate in both catalytic and stoichiometric reactions. Preliminary mechanistic studies demonstrate the dual role of the silver salt as a desulfurating reagent assisting the elimination of sulfur and as oxidant facilitating the PdII/Pd0/PdII catalytic cycle.

Tertiary Alkylative Suzuki-Miyaura couplings

Synthesis ◽  
2022 ◽  
Author(s):  
Takashi Nishikata ◽  
Tom Sheppard ◽  
Naoki Tsuchiya
Keyword(s):  
Oxidative Addition ◽  
Short Review ◽  
The Other ◽  
Side Reactions ◽  
Coupling Reactions ◽  
Other Hand ◽  
Alkyl Electrophiles ◽  
Carbon Bonds ◽  
Beta Hydride Elimination ◽  
Hydride Elimination

The Suzuki-Miyaura coupling is extremely useful to construct Csp2-Csp2 carbon bonds. On the other hand, Csp2-Csp3 coupling reactions are do not work well, and tert-alkylative Suzuki-Miyaura coupling is particularly challenging due to problematic oxidative addition and beta-hydride elimination side reactions. In this short review, we will introduce recent examples of tert-alkylative Suzuki-Miyaura couplings with tert-alkyl electrophiles or -boron reagents. The review will mainly focus on catalyst and product structures and the proposed mechanisms .

scholarly journals Palladium-catalyzed C–N and C–O bond formation of N-substituted 4-bromo-7-azaindoles with amides, amines, amino acid esters and phenols

2012 ◽  
Vol 8 ◽  
pp. 2004-2018 ◽  
Author(s):  
Rajendra Surasani ◽  
Dipak Kalita ◽  
A V Dhanunjaya Rao ◽  
K B Chandrasekhar
Keyword(s):  
Amino Acid ◽  
Bond Formation ◽  
Coupling Reaction ◽  
Cross Coupling ◽  
Amino Acid Esters ◽  
Coupling Reactions ◽  
Cross Coupling Reactions ◽  
Cross Coupling Reaction ◽  
Palladium Catalyzed ◽  
Acid Esters

Simple and efficient procedures for palladium-catalyzed cross-coupling reactions of N-substituted 4-bromo-7-azaindole (1H-pyrrole[2,3-b]pyridine), with amides, amines, amino acid esters and phenols through C–N and C–O bond formation have been developed. The C–N cross-coupling reaction of amides, amines and amino acid esters takes place rapidly by using the combination of Xantphos, Cs2CO3, dioxane and palladium catalyst precursors Pd(OAc)2/Pd2(dba)3. The combination of Pd(OAc)2, Xantphos, K2CO3 and dioxane was found to be crucial for the C–O cross-coupling reaction. This is the first report on coupling of amides, amino acid esters and phenols with N-protected 4-bromo-7-azaindole derivatives.

scholarly journals Dascylium

1912 ◽  
Vol 32 ◽  
pp. 57-67
Author(s):  
J. A. R. Munro
Keyword(s):  
The Other ◽  
The South ◽  
Scholarly Book ◽  
Other Hand ◽  
Lake Manyas ◽  
A Site ◽  
New Evidence

The identification of the lakes of the Cyzicene and the determination of the site of Dascylium, the seat of the Hellespontine satraps, are problems which have worried every scholar who has had to deal with the history or geography of the district. They are inseparable, because not only the names themselves, but also the statements of our ancient authorities, prove that Dascylium involves the neighbourhood of a Dascylite lake, and the Dascylite lake the neighbourhood of a Dascylium. Investigators have generally adopted one of two theories. Those who, like Dr. Richard Kiepert, have started from a place Dascylium, have fixed it at Daskeli or Diaskeli (Yaskil, Eskil Liman), a roadstead and village on the coast midway between Mudania and the Rhyndacus, and have conjured up a vanished lake in the valley of the Ulfer or Nilufer a few miles to the south. Since the publication of Heinrich Kiepert's large map this view has become an accepted tradition, and still holds the field. Those on the other hand who have started from a lake have usually found it in Lake Manyas, 10 or 12 miles south of Panderma, and have cast about for a site for Dascylium in its vicinity. Mr. F. W. Hasluck discusses the problems in his scholarly book on Cyzicus and the country adjacent to it, and regards this latter solution as the more probable of the two, but hazards a conjecture that Dascylium is perhaps to be sought farther eastward near Brussa. Some new evidence which has lately accrued from the recently published Hellenica Oxyrhynchia and from archaeological discoveries justifies a fresh examination of the questions.

Pd-Catalyzed Domino Reactions Involving Alkenes To Access Substituted Indole Derivatives

Synthesis ◽  
2020 ◽  
Vol 52 (19) ◽  
pp. 2731-2760
Author(s):  
Egle M. Beccalli ◽  
Michael S. Christodoulou ◽  
Francesca Foschi ◽  
Sabrina Giofrè
Keyword(s):  
Double Bond ◽  
The Other ◽  
Indole Derivatives ◽  
Domino Reactions ◽  
Recent Advances ◽  
Other Hand ◽  
Palladium Catalyzed ◽  
Intermolecular Reactions

Palladium-catalyzed domino reactions are advanced tools in achieving various nitrogen-containing heterocycles in an efficient and economical manner due to the reduced number of steps in the process. This review highlights recent advances in domino processes aimed at the synthesis of indole derivatives and polycyclic systems containing the indole nucleus in intra/intra- or intra/intermolecular reactions. In particular, we consider domino processes that involve a double bond in a step of the sequence, which allow the issue of regioselectivity in the cyclization to be faced and overcome. The different sections in this review focus on the synthesis of the indole nucleus and functionalization of the scaffold starting from different substrates that have been identified as activated starting materials, which involve a halogenated moiety or unactivated unsaturated systems. In the former case, the reaction is under Pd(0) catalysis, and in the second case a Pd(II) catalytic species is required and then an oxidant is necessary to reconvert the Pd(0) into the active Pd(II) species. On the other hand, the second method has the advantage that it uses easy available and inexpensive substrates.1 Introduction2 Indole Scaffold Synthesis2.1 Activated Substrates2.2 Unactivated Substrates3 Functionalization of Indole Scaffold3.1 Activated Substrates3.2 Unactivated Substrates4 Conclusions

Palladium-catalyzed Hiyama coupling reaction of arylsulfonyl hydrazides under oxygen

2015 ◽  
Vol 13 (16) ◽  
pp. 4647-4651 ◽  
Author(s):  
Hui Miao ◽  
Fenhua Wang ◽  
Shuangliu Zhou ◽  
Guangchao Zhang ◽  
Yang Li
Keyword(s):  
Coupling Reaction ◽  
Cross Coupling ◽  
Coupling Reactions ◽  
Aerobic Conditions ◽  
Cross Coupling Reactions ◽  
Palladium Catalyzed

Palladium-catalyzed Hiyama cross-coupling reactions of various arylsulfonyl hydrazides with a wide variety of aryl silanes have been achieved in good to excellent yields under simple aerobic conditions.

Efficient synthesis of 2-phenyl-3-substituted furo/thieno[2,3-b]quinoxalines via Sonogashira coupling reaction followed by iodocyclization and subsequent palladium-catalyzed cross-coupling reactions

RSC Advances ◽  
2016 ◽  
Vol 6 (87) ◽  
pp. 83901-83908 ◽  
Author(s):  
Tayebeh Besharati-Seidani ◽  
Ali Keivanloo ◽  
Babak Kaboudin ◽  
Tsutomu Yokomatsu
Keyword(s):  
Coupling Reaction ◽  
Cross Coupling ◽  
Coupling Reactions ◽  
Sonogashira Coupling ◽  
Efficient Synthesis ◽  
Cross Coupling Reactions ◽  
Sonogashira Coupling Reaction ◽  
Quinoxaline Derivatives ◽  
Palladium Catalyzed

In this paper, we report the successful synthesis of new 2-phenyl-3-substituted furo/thieno[2,3-b]quinoxaline derivatives from 2-chloro-3-methoxyquinoxaline and 2-chloro-3-(methylthio)quinoxaline by a three-step approach.

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