Iron-catalyzed aliphatic C-H functionalization to construct carbon-carbon bonds.

Area of Science:

• Organometallic Chemistry
• Catalysis
• Synthetic Organic Chemistry

Background:

• Cytochrome P450 enzymes catalyze alkane C-H abstraction but typically yield oxygenated products due to rapid oxygen rebound.
• Developing synthetic catalysts for selective C-H functionalization, especially for C-C bond formation, remains a significant challenge.
• Mimicking P450 activity while suppressing oxygenation is crucial for creating complex molecules.

Purpose of the Study:

• To develop a synthetic iron catalyst capable of undirected methylene C-H functionalization of alkanes.
• To achieve direct carbon-carbon bond formation with 1,4-quinones and azines, avoiding oxygen rebound.
• To enable selective alkylation of medicinally relevant scaffolds using feedstock alkanes.

Main Methods:

• Utilized an iron catalyst complexed with a bioinspired ligand.
• Employed hydrogen peroxide as the oxidant for C-H activation.
• Investigated reactions with diverse alkanes, 1,4-quinones, and azines.

Main Results:

• Demonstrated efficient, undirected methylene C-H functionalization of alkanes with 1,4-quinones and azines.
• Achieved direct formation of carbon-carbon bonds, suppressing the typical oxygen rebound pathway.
• Showcased predictable site selectivities in complex molecules based on steric, electronic, and stereoelectronic factors.

Conclusions:

• The developed iron/bioinspired ligand catalyst overcomes the oxygenation limitation inherent in P450 enzymes.
• This system provides a novel and promising strategy for the selective alkylation of quinones and heterocycles using readily available alkanes.
• The findings open new avenues for synthesizing complex organic molecules with potential medicinal applications.