Copper-Catalyzed Benzylic C−H Oxygenation under an Oxygen Atmosphere via N-H Imines as an Intramolecular Directing Group
摘要:
Copper-catalyzed benzylic C-H oxygenation under an oxygen atmosphere was developed starting from carbonitriles and Grignard reagents via N-H imine intermediates. The present process is characterized by the following two-step sequence in a one-pot manner: (1) addition of Grignard reagents to carbonitriles to form N-H imines and (2) benzylic C-H oxygenation (C=O bond formation) triggered by 1,5-hydrogen atom transfer with transient iminyl copper species.
An improved synthetic strategy for 1-substituted 4-H phthalazines using a convenient, three-step reaction sequence under mild conditions is described. The protocol involves condensation of hydrazine hydrate with o-ketobenzaldehydes derived through the Pb(OAc)4 oxidation of the N-acylhydrazones of salicylaldehydes. This pathway is of high practical value since a wide variety of substituted acylhydrazides