10.1016/j.tetlet.2012.07.093
The study describes a new and efficient method for synthesizing indolo[3,2,1-jk]carbazoles through palladium-catalyzed intramolecular cyclization of N-(2-bromoaryl)carbazoles. The reaction involves forming carbon-carbon bonds via intramolecular arylation, which proceeds with the cleavage of C–X and C–H bonds on the carbazole ring. Various substituted N-aryl carbazole substrates, containing both electron-donating and electron-withdrawing groups, were explored under optimized conditions. The study successfully yielded indolo[3,2,1-jk]carbazoles with high thermostability, good fluorescence properties, and electron-donor potential, making them promising candidates for applications in organic electronics and material chemistry.
10.1021/acs.orglett.1c00515
The research aims to disclose an efficient synthetic method for N-arylphenothiazines from o-sulfanylanilines without the use of transition metals. The study focuses on an N- and S-arylation sequence that enables the synthesis of a wide variety of N-arylphenothiazines, including the one-pot synthesis from readily available modules. Key chemicals used in the process include o-sulfanylanilines, aryne intermediates, potassium t-butoxide in N,N-dimethylacetamide (DMA), and various substituted o-sulfanylanilines. The research concludes that the ortho arylthio group in o-sulfanylanilines acts as a masked thiolate and an aryl donor moiety for N-arylation, and that the aromatic rings do not require activation by electron-withdrawing groups for the efficient N- and S-arylation sequence. The method expands the scope of available N-arylphenothiazines, which are significant in medicinal chemistry, materials science, and as photoredox catalysts, organic semiconductor compounds, and fluorescent compounds.
10.1002/jhet.5570340205
The research aimed to explore the reaction of guanidine carbonate with various ortho-fluorobenzaldehydes as a potential route for preparing 2-aminoquinazolines. The study successfully synthesized eleven new 2-aminoquinazolines in low to moderate yields, with the best results obtained when ortho-fluorobenzaldehydes had an electron-withdrawing substituent at the other ortho position. The researchers encountered complex mixtures with certain substrates, such as 2-fluorobenzaldehyde, 2,5-difluorobenzaldehyde, and 2-fluoro-5-methoxybenzaldehyde, which were not resolved. Key chemicals used in the process included guanidine carbonate, N,N-dimethylacetamide as the solvent, and various ortho-fluorobenzaldehydes with different substituents. The conclusions highlighted the effectiveness of the method in synthesizing 2-aminoquinazolines, especially when electron-withdrawing groups were present, and the limitations when dealing with certain substrates that led to unresolved complex mixtures.
10.1021/ol902651j
The study investigates the Pd-catalyzed decarboxylative benzylation of benzyl diphenylglycinate imines to form new Csp3-Csp3 bonds. The key chemicals involved include benzyl diphenylglycinate imines as the substrates, Pd(OAc)2 as the palladium catalyst, and rac-BINAP as the bidentate ligand. The reaction is accelerated by microwave irradiation and takes place in dimethylacetamide (DMA) solvent. The study identifies optimal reaction conditions, such as a 0.1 M solution with 3 mol % Pd(OAc)2 and 20 mol % rac-BINAP, yielding the desired benzylation products in high yield. The research explores the scope of this reaction by varying the imine and ester components, finding that heterocyclic functionalities like furan, indole, thiazole, and pyridine are well-tolerated. The study also proposes a preliminary mechanism involving the reduction of Pd(OAc)2 to form the active catalyst, insertion into the ester C-O bond, decarboxylation to generate a 2-azaallylPd(II) intermediate, and subsequent reductive elimination or nucleophilic attack to form the final products. This work expands the scope of Pd-catalyzed decarboxylative alkylation strategies and has potential applications in the synthesis of complex organic molecules.
10.1002/chem.201101529
The research focuses on the development of a novel synthetic methodology for the preparation of C1-symmetric bis(diphenylphosphino)biphenyl ligands, which are crucial in asymmetric catalysis. The study aimed to overcome the challenges associated with the synthesis of these ligands, particularly the undesired intramolecular cyclization leading to phosphafluorene formation. The researchers successfully developed a palladium-catalyzed C–P coupling reaction that does not require additional ligands and avoids the formation of phosphafluorene in most cases. This method allows for the rapid synthesis of a variety of substituted ortho,ortho'-bis(diphenylphosphino)biphenyls in moderate-to-excellent yields and significantly reduced reaction times compared to previous methods. Key chemicals used in the process include ortho,ortho’-dihalobiphenyl precursors, diphenylphosphine (HPPh2), palladium acetate (Pd(OAc)2) as the catalyst, potassium acetate (KOAc) as the base, and N,N-dimethylacetamide (DMA) as the solvent. The study's conclusions open new pathways for the synthesis of more complex diphosphines based on C1- or C2-symmetric biaryl scaffolds and has implications for the direct synthesis of enantiomerically pure C1-symmetric biaryl-based diphosphines.
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