ortho-Allylation of 1- Arylpyrazole with Allyl Phenyl Ether via Iron-Catalyzed C–H Bond Activation under Mild Conditions

Abstract

An iron salt and a bipyridine-type ligand catalyze the ortho-allylation of 1-arylpyrazoles and congeners with allyl phenyl ether under mild condi- tions (0 °C). The ligand, an organozinc base, and the nature of the allylating reagent are crucial for the success of this reaction. Under these conditions, a competitive phenylation reaction is largely retarded, and cross-coupling of the organozinc with the allyl electrophile is minimized. The reaction may proceed via iron-catalyzed ortho C-H activation to form a metallic intermediate, which then reacts with the allyl ether in a g selective fashion.

Publication
Asako, S.; Norinder, J.; Ilies, L.; Yoshikai, N.; Nakamura, E. Adv. Synth. Catal. 2014, 356, 1481-1485.