78176-92-8

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• 78176-93-9 (dihydro-3',4' naphtyl-1')-2 benzothiophene 
• 529-34-0 3,4-dihydronaphthalene-1(2H)-one 
• 95-15-8 Benzo[b]thiophene 
• 90-11-9 1-Bromonaphthalene 
• 120878-74-2 α,α-diphenyl-benzo[b]thien-2-ylmethanol 
• 1170724-05-6 methyl(2-(2-(naphthalen-1-yl)ethynyl)phenyl)sulfane 
• 38262-42-9 1-naphthyl mesylate 
• 446-48-0 o-fluorobenzyl bromide 
• 1104637-69-5 C₁₃H₁₂BNO₄S 
• 98437-23-1 benzo[b]thiophene-2-boronic acid 
• 1144-13-4 naphthalen-1-yl N,N-dimethylsulfamate 
• 1415237-87-4 (PhCH₂CHC(COOMe)₂)GaCl₃ 
• 141580-93-0 2-ethynylbenzo[b]thiophene 
• 63724-94-7 2-deuteriobenzothiophene 

Relevant academic research and scientific papers

Pd-Catalyzed Suzuki-Miyaura and Hiyama-Denmark Couplings of Aryl Sulfamates

Using a recently discovered precatalyst, the first Pd-catalyzed Suzuki-Miyaura reactions using aryl sulfamates that occur at room temperature are reported. In complementary work, it is demonstrated that a related precatalyst can facilitate the coupling of aryl silanolates, which are less toxic and reactive nucleophiles than boronic acids with aryl chlorides. By combining our results using modern electrophiles and nucleophiles, the first Hiyama-Denmark reactions using aryl sulfamates are reported.

C-H Arylation of Thiophenes with Aryl Bromides by a Parts-per-Million Loading of a Palladium NNC-Pincer Complex

A palladium NNC-pincer complex efficiently catalyzed the direct arylation of thiophene derivatives with extremely low palladium loadings of the order of parts per million. Thus, the reaction of various thiophenes with aryl bromides in the presence of 25-100 mol ppm of chlorido[(2-phenyl-κ- C 2)-9-phenyl-1,10-phenanthroline-κ 2- N, N ′]palladium(II) NNC-pincer complex, K 2CO 3, and pivalic acid in N, N -dimethyl acetamide afforded the corresponding 2- or 5-arylated thiophenes in good to excellent yields. A combination of the present C-H arylation and Hiyama coupling with the same NNC-pincer complex provides an efficient synthesis of unsymmetrical 2,5-thiophenes with catalyst loadings at mol ppm levels.

Nickel-catalyzed and Li-mediated regiospecific C-H arylation of benzothiophenes

A nickel-based catalytic system for the regiospecific C2-H arylation of benzothiophene has been established. NiCl2(bpy) is used as a catalyst in combination with LiHMDS as a base in dioxane. The catalytic system is applicable to a variety of functionalized benzothiophenes, as well as other heteroarenes including thiophene, benzodithiophene, benzofuran and selenophene in combination with iodo aryl electrophiles. The role of LiHMDS as a uniquely potent base and a postulated mechanism are discussed. The applicability of this system is finally demonstrated for the synthesis of an intermediate of an active pharmaceutical ingredient.

Palladium/Copper Dual Catalysis for the Cross-Coupling of Aryl(trialkyl)silanes with Aryl Bromides

Whereas aryl(trialkyl)silanes are considered to be ideal organometallic reagents for cross-coupling reactions owing to their stability, low toxicity, solubility, and easy accessibility, they are generally inert under typical cross-coupling conditions. Disclosed herein is a palladium/copper catalytic system that enables the cross-coupling of trimethyl, triethyl, tert-butyldimethyl, and triisopropyl aryl silanes with aryl bromides. This process is applicable to the sequential C?H and C?Si bond arylation of thiophenes and the synthesis of poly(thiophene–fluorene)s.

Ag(I)-C-H Activation Enables Near-Room-Temperature Direct α-Arylation of Benzo[ b]thiophenes

The first example of near-room-temperature α-arylation of benzo[b]thiophenes is reported. The discovery rests on the observation of a switch in α-/β-regioselectivity at different loadings of Pd2(dba)3·CHCl3 in the coupling between benzo[b]thiophene and 4-iodotoluene. We show that this unprecedented regioselectivity switch is driven by a Ag(I)-mediated C-H activation at the α-C-H position, which becomes the dominant mode of reactivity at low concentrations of Pd. Competition experiments, kinetic studies, KIE, and D/H scrambling experiments have been carried out supporting this mechanism.

Mechanistic study of an improved Ni precatalyst for Suzuki-Miyaura reactions of aryl sulfamates: Understanding the role of Ni(I) species

Nickel precatalysts are potentially a more sustainable alternative to traditional palladium precatalysts for the Suzuki-Miyaura coupling reaction. Currently, there is significant interest in Suzuki-Miyaura coupling reactions involving readily accessible phenolic derivatives such as aryl sulfamates, as the sulfamate moiety can act as a directing group for the prefunctionalization of the aromatic backbone of the electrophile prior to cross-coupling. By evaluating complexes in the Ni(0), (I), and (II) oxidation states we report a precatalyst, (dppf)Ni(σ-tolyl)(Cl) (dppf = 1,1'-bis(diphenylphosphino)-ferrocene), for Suzuki-Miyaura coupling reactions involving aryl sulfamates and boronic acids, which operates at a significantly lower catalyst loading and at milder reaction conditions than other reported systems. In some cases it can even function at room temperature. Mechanistic studies on precatalyst activation and the speciation of nickel during catalysis reveal that Ni(I) species are formed in the catalytic reaction via two different pathways: (i) the precatalyst (dppf)Ni(σ-tolyl)(Cl) undergoes comproportionation with the active Ni(0) species; and (ii) the catalytic intermediate (dppf)Ni(Ar) (sulfamate) (Ar = aryl) undergoes comproportionation with the active Ni(0) species. In both cases the formation of Ni(I) is detrimental to catalysis, which is proposed to proceed via a Ni(0)/Ni(II) cycle. DFT calculations are used to support experimental observations and provide insight about the elementary steps involved in reactions directly on the catalytic cycle, as well as off-cycle processes. Our mechanistic investigation provides guidelines for designing even more active nickel catalysts.

[4 + 2] Annulation of Donor-Acceptor Cyclopropanes with Acetylenes Using 1,2-Zwitterionic Reactivity

A new process for the [4 + 2] annulation of donor-acceptor cyclopropanes with acetylenes under the effect of anhydrous GaCl3 using 1,2-zwitterion reactivity was elaborated. The reaction opens access to substituted dihydronaphthalenes, naphthalenes, and other fused carbocycles. The direction of the reaction can be efficiently controlled by temperature.

Bulky α-diimine palladium complexes: Highly efficient for direct C-H bond arylation of heteroarenes under aerobic conditions

Through the strategy to enhance the bulkiness on both the backbone and the N-aryl moieties, we designed and synthesized a type of bulky α-diimine palladium complex (i.e., {[Ar-NC(R)-C(R)N-Ar]PdCl2, (Ar = 2-benzhydryl-4,6-dimethylphenyl)}, C1, R = H; C2, R = An; C3, R = Ph). The structures of these palladium complexes were well characterized, while C1 and C3 were further characterized by X-ray diffraction. The catalytic performances of the precatalysts were screened for direct C-H bond arylation of heteroarenes. The bidentate N,N-palladium complex C3 with both a backbone and N-aryl bulkiness was found to be a highly efficient precatalyst under aerobic conditions. With a low palladium loading of 0.5-0.1 mol%, a variety of heteroarenes with challenging bulky steric aryl bromides as well as heteroaryl bromides are all applicable for this cross-coupling reaction.

Synthesis of arylboronates by boron-induced ipso-deantimonation of triarylstibanes with boron trihalides and its application in one-pot two-step transmetallation/cross-coupling reactions

The reaction of triarylstibanes (1) with boron trihalides (BCl3, and BBr3) afforded arylboron dihalides (2) by utilizing all the three aryl groups on the antimony. Boron intermediates (2) were transformed to arylboronates (3) in good to excellent yields by treatment with methanol and 1,3-propanediol. Further, the Pd-catalyzed reactions of 2 with organic halides such as 1-bromonaphthalene and benzoyl chloride in the presence of H2O afforded the corresponding cross-coupling products, unsymmetrical biaryls (4) and ketones (5), in moderate to good yields. The potential energy surfaces for the transmetallations of triarylstibanes (1) with BCl3 affording 2 were determined by molecular orbital calculations. The analyses of substituent effects on theoretically calculated reactivities showed the importance of the resonance effects of the ring substituents on these transmetallations.

Aerobic and Efficient Direct Arylation of Five-Membered Heteroarenes and Their Benzocondensed Derivatives with Aryl Bromides by Bulky α-Hydroxyimine Palladium Complexes

In the present work, a series of α-hydroxyimine palladium complexes with bulky substituents (i.e., {[Ar-N=C(R)-C(R)2-OH]PdCl2} (C1, R = Me, Ar = 2-diphenylmethyl-4,6-dimethylphenyl; C2, R = Me, Ar = 2,6-bis(diphenylmethyl)-4-methylphenyl; C3, R = Me, Ar = 2,6-bis(diphenylmethyl)-4-methyoxylphenyl; C4, R = Me, Ar = 2,6-bis(diphenylmethyl)-4-chlorophenyl; C5, R = Ph, Ar = 2,6-dimethylphenyl; C6, R = Ph, Ar = 2,6-diisopropylphenyl)) were synthesized and characterized. The structures of palladium complexes C1 and C2 were determined by X-ray diffraction. These bidentate N,O-palladium complexes were applied for direct arylation under aerobic conditions. The effects of the reaction conditions and ligand substitution on the catalytic activity were evaluated. Upon a low palladium loading of 0.5 mol %, the bulky palladium complex C6 was successfully used to catalyze the cross-coupling of a variety of five-membered heteroarenes and their benzo-condensed derivatives with (hetero)aryl bromides. The mechanistic investigation on the direct arylation supported the involvement of a Pd(0)/Pd(II) CMD process.