One‐Pot Synthesis of Benzene and Pyridine Derivatives via Copper‐Catalyzed Coupling Reactions

Abstract

A highly efficient one‐pot synthesis of polysubstituted pyridine has been achieved through copper‐catalyzed oxidative sp3 C−H coupling of acetophenones with toluene derivatives. Besides, the polysubstituted benzene was obtained through copper‐catalyzed coupling of acetophenones. Both of the reactions exhibited a good functional group tolerance to produce a 2,4,6‐triphenylpyridine or 1,3,5‐triarylbenzene in high yields. Compared with previous methods, these transformations allow a highly flexible and efficient preparation of substituted pyridines and benzenes.magnified image

A New Synthetic Pathway to Triphenylpyridines via Cascade Reactions Utilizing a New Iron‐Organic Framework as a Recyclable Heterogeneous Catalyst

“…First, many iron and copper salts were used as the catalyst for the cascade reactions between acetophenone and phenylacetic acid with ammonium acetate as a nitrogen source under standard conditions. The reaction afforded more than 50 % yields in the presence of FeCl 2 , FeCl 3 , and Fe 2 (SO 4 ) 3 (Entries 1-3, Table 2), while lower yields were detected for the case of Fe(NO 3 ) 3 , Fe(acac) 3 , and Fe(OAc) 2 (Entries 4-6, Table 2). Moreover, it was noted that copper and nickel salts exhibited low activity for the transformation (Entries 7-9, Table 2).…”

“…Simultaneously, (1a) was isomerized to 1-phenylethen-1-ol (A), and the reaction of (A) with ammonium acetate led to the formation of 1-phenylethen-1amine (B) with water and acetic acid being released. [3,4] Subsequently, the condensation between (B) and (6) (6) in a HOTf-catalyzed one-pot synthesis of pyridine derivatives from acetophenones and benzylamines. [4] As the synthesis of 2,4,6-triphenylpyridine from acetophenone and phenylacetic acid with ammonium acetate as a nitrogen source utilizing the VNU-22 catalyst was performed in chlorobenzene phase, the leaching of iron species during the experiment must be investigated.…”

“…Han et al previously reported a Cu(OTf ) 2 -catalyzed one-pot formation of 2,4,6-triphenylpyridines from acetophenones and toluenes. [3] Zhang et al demonstrated a HOTf-catalyzed one-pot generation of these heterocycles from acetophenones and benzylamines. [4] Rohokale et al synthesized 2,4,6-triphenylpyridines using a photoredox catalysis approach.…”

Amalgamation of CSR and DES: An Energy Efficient Protocol for the One‐Pot Synthesis of 2,4,6‐ Triaryl Pyridine Derivatives.

“…A wide range of catalysts and synthetic methods have been investigated for one‐pot synthesis of 2,4,6‐triaryl pyridine derivatives . Different catalysts namely silica sulfuric acid (SSA), cyanuric chloride, trichloro cyanuric acid, NBS, molecular iodine, nanocrystalline MgAl 2 O 4, L ‐proline etc.…”

Synthesis of Pyrimidines with Ammonium Acetate as Nitrogen Source Under Solvent‐Free Conditions

“…Recently, our group reported three-component tandem reactions of acetophenone, toluene, and NH 4 OAc using copper as the catalyst for the preparation of 2,4,6-triphenylpyridines. [10] Others groups (e. g., Shingare group, [11] Bamoharram group, [12] and Chen group [13] ) were successively reported a single-step procedure for the synthesis of multisubstituted pyridines using NH 4 OAc as nitrogen source. The advantage of utilizing ammonium acetate as the nitrogen source is not only the starting material which is economically advantageous and readily available, but also simple and user-friendly in operation.…”