The Regioselective Arylation of 1,3-Benzodioxoles

The direct arylation of 1,3-benzodioxole and 2,2-difluorobenzo[1,3]dioxole with 26 different aryl bromides yields the respective 4-substitued products in yields of >80% requiring between 0.05-1 mol % Na2PdCl4, 30 mol % pivalic acid, 1.3 equivs. K2CO3 and ca. 250 equivs. of diethylacetamide per Pd at T=120 degrees C. The nature of the amide and the concentration of the reactants are crucial for the optimization of the reaction conditions. The primary role of the acetamide is that of a ligand to Pd, it is not needed as a solvent.

Automated summary

The direct arylation of 1,3-benzodioxole and 2,2-difluorobenzo[1,3]dioxole with various aryl bromides yields 4-substituted products in high yields. The nature of the amide and the concentration of the reactants play crucial roles in optimizing reaction conditions. Acetamide acts as a ligand to Pd, not as a solvent, in this reaction.