Functionalization of a Simple Dithienylethene via Palladium-Catalyzed Regioselective Direct Arylation

Abstract

The direct arylation on the thienyl groups of a diarylethene with various aryl iodides efficiently provided arylated dithienylethenes under palladium catalysis. Unsymmetrically substituted dithienylethenes were also synthesized by this protocol. This procedure allows a rapid access to a variety of aryl-substituted dithienylethenes from a single substrate of a simple dithienylethene.

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

“…of aryl iodides different from those used for the selective monoarylation of compound 143. [105] Itami, Shinokubo and co-workers also demonstrated that the site selectivity of the monoarylation of compound 143 was controlled by the proper choice of the palladium ligand. In fact, they found that 143 underwent b-arylation by treatment with 3 equiv.…”

“…[61] Again in 2011, Itami, Shinokubo and co-workers employed a PdCl 2 /2,2'-bipyridyl/Ag 2 CO 3 system for the direct arylation of 1,2-di(2-methylthien-3-yl)perfluorocyclopentene (143) with aryl iodides. [105] As shown in Scheme 66, the procedure allowed a rapid access to monoarylated dithienylcyclopentenes 144 in modest yields. [105] Compounds 144 were then shown to be useful substrates for the synthesis of unsymmetrically disubstituted 1,2-dithienylcyclopentenes 145 ( Figure 23) by PdCl 2 /2,2'-bipyridyl/Ag 2 CO 3 -catalyzed reaction with 3 equiv.…”

“…[105] As shown in Scheme 66, the procedure allowed a rapid access to monoarylated dithienylcyclopentenes 144 in modest yields. [105] Compounds 144 were then shown to be useful substrates for the synthesis of unsymmetrically disubstituted 1,2-dithienylcyclopentenes 145 ( Figure 23) by PdCl 2 /2,2'-bipyridyl/Ag 2 CO 3 -catalyzed reaction with 3 equiv. of aryl iodides different from those used for the selective monoarylation of compound 143.…”

“…Until a few years ago, rare examples of the b-selective intermolecular arylations of thiophenes had been reported in the literature, [105,111] but in recent years some successful protocols to achieve these reactions have been developed. In 2009, Doucet and co-workers reported that 2,5-dimethylthiophene (152) underwent phosphine-free PdA C H T U N G T R E N N U N G (OAc) 2 -catalyzed reaction with aryl bromides to give 3-aryl-2,5-dimethylthiophenes in moderate to good yields (Scheme 73).…”

Toward an Ideal Synthesis of (Bio)molecules through Direct Arene Assembling Reactions

“…9 The Shinokubo group and our group applied direct CH arylation methods, including our β-selective arylation, to the functionalization of a simple dithienylethene. 10 Moreover, a synthesis of spirocyclic thiophenes containing various functional groups, which are potent ligands for σ 1 receptors, was accomplished by our group and the Wünsch group using Pd catalysis as shown in Scheme 3.…”