Direct multiple C–H bond arylation reaction of heteroarenes catalyzed by cationic palladium complex bearing 1,10-phenanthroline

Shibahara, Fumitoshi; Yamaguchi, Eiji; Murai, Toshiaki

doi:10.1039/b920794e

Cited by 195 publications

(57 citation statements)

References 41 publications

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“…The reaction of Zn II porphyrin 1-Zn (M = Zn) with 3,5-dimethylbromobenzene afforded none of the diarylated product and the corresponding monoarylated porphyrin in 33 % yield. [13,14] According to Fagnou and co-workers, [9f, 10a, 15] the most plausible mechanism for the arylation reaction consists of the following elementary steps (Scheme 1 a): 1) oxidative addition of an aryl bromide to Pd 0 to produce an arylpalladium bromide, 2) bromide-pivalate exchange to provide an arylpalladium pivalate, 3) CMD of the porphyrin with the arylpalladium pivalate to form an aryl(porphyrinyl)palladium, and 4) reductive elimination to result in arylation of the porphyrin and liberation of the initial Pd 0 complex. No conversion was observed in the reaction of free-base porphyrin 1-H 2 (M = 2H) because a palladium cation was captured by the substrate.…”

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confidence: 99%

Palladium‐Catalyzed β‐Selective Direct Arylation of Porphyrins

et al. 2011

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Porphyrins are an important class of aromatic compounds that exhibit interesting optical and electrochemical properties and have attracted much attention as key components of functional materials and supramolecular architectures.[1] Creation of new porphyrins that feature intriguing properties is hence essential in developing the chemistry and applications of functional p-rich molecules. Peripheral functionalization of porphyrins can effectively modify the electronic and steric nature of the parent porphyrins, and is thus useful when investigating new porphyrins.[2] Among the possible functionalizations, arylation is promising since the introduced aryl groups can induce electronic perturbation through extension of p conjugation. Nucleophilic addition of aryllithium reagents to meso-unsubstituted porphyrins followed by oxidation can be employed for peripheral arylation reactions. [2c,d, 3] The nucleophilic arylation reaction inherently lacks functional-group compatibility because of the high reactivity of aryllithium reagents. Presently, the most reliable and chemoselective functionalization is based on palladiumcatalyzed cross-coupling reactions. [4,5] However, the crosscoupling strategy always requires preparation of halogenated [5,6] or metalated [7,8] porphyrins prior to arylation. More straightforward and efficient methods for peripheral arylation of porphyrins are thus needed.Transition-metal-catalyzed direct CÀH arylation of arenes with aryl halides has been rapidly emerging as a promising alternative to traditional cross-coupling arylations because preparations of aryl metal reagents can be omitted. [9][10][11] We envisaged that the direct arylation would be applicable to porphyrins. After extensive screening of porphyrin substrates and reaction conditions, we found that the pivalate-assisted conditions developed by Fagnou and co-workers, with some modifications, are effective for the synthesis of meso-free Ni II porphyrins. [9f, 10a] Treatment of the Ni II complex of 5,10,15-tris(3,5-di-tert-butylphenyl)porphyrin (1-Ni) with aryl halides in the presence of pivalic acid, [12] potassium carbonate, and catalytic amounts of palladium acetate and DavePhos in N,Ndimethylacetamide (DMA) at 100 8C resulted in diarylation with satisfactory efficiency (Table 1). To our surprise, the reaction proceeded exclusively at the b positions adjacent to the free meso position with excellent selectivity, and no mesoarylated products were detected. Although the sequential iridium-catalyzed borylation/palladium-catalyzed SuzukiMiyaura coupling had been the only efficient and practical method for b-selective arylation, [8] this sequence often suffers from the gradual protodeborylation of borylated porphyrins in protic media during purification and cross-coupling processes. Naturally, the present direct method is much more efficient and does not suffer from such demetalation. Moreover, this method is the first palladium-catalyzed reaction that selectively functionalizes the b positions of porphyrins.

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Palladium‐Catalyzed β‐Selective Direct Arylation of Porphyrins

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“…[139] A year earlier, Shibahara and Murai had discovered that the cationic complex PdA C H T U N G T R E N N U N G (phen) 2 A C H T U N G T R E N N U N G (PF 6 ) 2 bearing the 1,10-phenanthroline ligand was able to catalyze the efficient bis-arylation of 1-methylpyrrole (44a) with a large molar excess of 4-trifluoromethyliodobenzene in DMA at 150 8C in the presence of Cs 2 CO 3 as the base (Scheme 108). [140] The reaction conditions shown in Scheme 107 were also found to be suitable for the 2,5-bis-arylation of thiophene, 3-methylthiophene and benzo[b]furan. [140] In 2009, Pellet-Rostaing, Lemaire and co-workers reported that the reaction of 8-oxo-5,5,7,8-tetrahydroindolizine (206) with 1.2 equiv.…”

Section: Scheme 101 a C H T U N G T R E N N U N G [Rucl 2 A C H T U mentioning

confidence: 94%

“…[140] The reaction conditions shown in Scheme 107 were also found to be suitable for the 2,5-bis-arylation of thiophene, 3-methylthiophene and benzo[b]furan. [140] In 2009, Pellet-Rostaing, Lemaire and co-workers reported that the reaction of 8-oxo-5,5,7,8-tetrahydroindolizine (206) with 1.2 equiv. of (hetero)aryl bromides in NMP at 100 8C in the presence of 2 equiv.…”

Section: Scheme 101 a C H T U N G T R E N N U N G [Rucl 2 A C H T U mentioning

confidence: 94%

Cross‐Coupling of Heteroarenes by CH Functionalization: Recent Progress towards Direct Arylation and Heteroarylation Reactions Involving Heteroarenes Containing One Heteroatom

et al. 2014

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In recent years, transition metal-catalyzed direct (hetero)arylation reactions of heteroarenes with (hetero)aryl halides and pseudohalides have received significant attention as eco-friendly and economic alternatives to classical methods for the construction of heteroaryl-(hetero)aryl C À C bonds by transition metal-catalyzed cross-couplings involving the use of stoichiometric amounts of organometallic reagents. This critical review with 430 references covers the results obtained in the period January 2009 to February 2013 in the area of the transition metal-catalyzed direct inter-and intramolecular (hetero)arylation reactions of heteroarenes containing one heteroatom. Particular attention has been given to illustrate chemo-and site selectivity aspects of these reactions as well applications of these C À C bond forming reactions in the synthesis of pharmaceutically relevant compounds, natural products and their analogues and precursors. The most recent advancements into the mechanism(s) of these reactions have also been briefly reported.

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“…11 However, a direct C–H bond arylation of imidazopyridine 1 is limited to a few examples of cationic Pd-catalyzed C-1 arylation of C-3-substituted imidazo[1,5- a ]pyridines. 12 To the best of our knowledge, there are no reports on a direct C-3 C–H arylation of 1 . Based on our previous regioselective Pd-catalyzed electrophilic arylation of indolizines, 13 we envisioned that the structural similarity of imidazo[1,5- a ]pyridine and indolizine might allow the same type of transformations to occur.…”

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Palladium-catalyzed Highly Regioselective C-3 Arylation of Imidazo[1,5-a]pyridine

Huang¹,

Giokaris²,

Gevorgyan³

2011

Chemistry Letters

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Direct multiple C–H bond arylation reaction of heteroarenes catalyzed by cationic palladium complex bearing 1,10-phenanthroline

Abstract: A cationic palladium complex bearing 1,10-phenanthroline ligand is found to catalyze direct C-H arylation reactions of heteroarenes with aryl iodides to give mono-, di-, or tri-arylated products selectively.

Cited by 195 publications

References 41 publications

Palladium‐Catalyzed β‐Selective Direct Arylation of Porphyrins

Palladium‐Catalyzed β‐Selective Direct Arylation of Porphyrins

Cross‐Coupling of Heteroarenes by CH Functionalization: Recent Progress towards Direct Arylation and Heteroarylation Reactions Involving Heteroarenes Containing One Heteroatom

Palladium-catalyzed Highly Regioselective C-3 Arylation of Imidazo[1,5-a]pyridine

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