Development of highly structured non-heme iron catalysts for selective C-H group oxidations

摘要

Catalytic oxidation reactions of hydrocarbons that occur in the active site of metalloenzymes exhibit high efficiency and exquisite regio- and stereoselectivity under mild experimental conditions. We describe the efficient and selective oxidation of alkanes using a family of highly structured non-heme iron catalysts that introduce sterically bulky pinene groups. In this way, it is possible to modulate the selectivity, which depends on the combination of the chirality of the catalyst, the nature of the diamine backbone and the presence of a cavity-like site surrounding the metal center. We present an optimized reaction protocol for efficient oxidation of alkanes with the readily available [Fe(CF3SO3)2(mcp)] catalyst, which shows enhanced selectivity toward methylenic sites. Finally, we describe a new family of iron catalysts to systematically study the steric influence of the ligand in regioselectivity. We observe a strong relationship between the bulk of the silyl substituent and the regioselectivity offered by the catalyst.