Copper-Catalyzed Inter/Intramolecular N-Alkenylation of Benzimidazoles via Tandem Processes Involving Selectively Mild Iodination of sp(3) C-H Bond at alpha-Position of Ester

摘要

Inter/intramolecular approaches to sp(2) C-N bond formation of N-alkenyl benzimidazoles have been accomplished in the presence of an iodide anion associated with a copper catalyst. Both intermolecular and intramolecular reactions included tandem processes, in which selective iodination of sp(3) C-H bond at the alpha-position of ester under mild conditions was demonstrated for the first time. Tandem reactions involving sp3 C-H activation via alpha-iodo ester intermediate under copper catalysis efficiently provided more than 20 novel azole compounds, and free radicals were not involved in this transformation.