N-Arylation of amines, amides, imides and sulfonamides with arylboroxines catalyzed by simple copper salt/EtOH system

• Zhang-Guo Zheng,
• Jun Wen,
• Na Wang,
• Bo Wu and
• Xiao-Qi Yu

Beilstein J. Org. Chem. 2008, 4, No. 40, doi:10.3762/bjoc.4.40

• -containing substrates with arylboroxine conducted in protic solvent only with the use of copper salts has not been explored previously. Results and Discussion Firstly, we chose phthalimide and phenylboroxine as model substrates to optimize the catalytic conditions (copper source, temperature, solvent, amount

• of catalyst) to achieve the best results in the cross-coupling reactions (Scheme 2). Several simple copper salts were tested as copper sources to promote the coupling reaction with methanol as solvent. As shown in Table 1, most copper salts (20 mol %) that were used gave the desired products in high

• yields (Table 1, entries 1–10), and the counterion did not play a significant role. This result is much better than previously reported [10] for a similar catalytic system. However, the time required to accomplish this coupling reaction is quite different with these copper salts. In the case of Cu(OTf)2