Establishment of Broadly Applicable Reaction Conditions for the Palladium-Catalyzed Direct Arylation of Heteroatom-Containing Aromatic Compounds

Abstract

Conditions for the palladium-catalyzed direct arylation of a wide range of heterocycles with aryl bromides are reported. Those conditions employ a stoichiometric ratio of both coupling partners, as well as a substoichiometric quantity of pivalic acid, which results in significantly faster reactions. An evaluation of the influence of the nature of the aryl halide has also been carried out.

Palladium-catalyzed Direct Arylation Approach to Synthesize Naphthalene Bisimide-based Low-band-gap Polymers

“…5,6 With these benefits, the direct arylation presents considerable potential for overcoming the drawbacks of conventional cross-coupling reactions, and it can be an efficient alternative method for the synthesis of conjugated polymers. 710 The synthesis of DA alternating low-band-gap polymers, poly(thieno [3,4-c]pyrrole-4,6-dione-altdithiophene) (PTPDDT) 11 (M n µ 50000) and poly(4,4-dialkylcyclopenta[2,1-b:3,4-b¤]dithiophene-alt-2,1,3-benzothiadiazole) (PCPDTBT) 12 (M n µ 40000) by direct arylation was recently reported.…”

Development of Synthetic Method for ^|^pi;-Conjugated Polymers via Direct Arylation Polycondensation

“…13 The reaction of 3,3 ,4,4 tetramethylbithiophene with 2,7 dibromo 9,9 dioctyl uorene proceeded in the presence of Pd(OAc) 2 (2 mol%), PCy 3 ·HBF 4 (4 mol%), pivalic acid (30 mol%), and K 2 CO 3 (2.5 equiv.) 14 to afford the target polymer in good yield (Table 1, entry 1). 13 Other phosphine ligands were less effective than PCy 3 ·HBF 4 .…”

Synthesis of Soluble Polythiophene Partially Containing 3,4-Ethylenedioxythiophene and 3-Hexylthiophene by Polycondensation

“…Table 1 summarizes the reaction conditions, and Figure 3 shows the GPC curves of as-prepared polymers obtained by these conditions. Because PCy 3 ·HBF 4 was reported as an effective ligand for Pd-catalyzed direct C-H coupling reaction of thiophene derivatives [33] [34], the catalytic system of Pd(OAc) 2 with PCy 3 ·HBF 4 was examined first (entry 1-3). When DMAc was used as a solvent, polyHE5T with the highest molecular weight was obtained (entry 2).…”