Enantioselective Intermolecular Radical C-H Amination.

Area of Science:

• Organic Chemistry
• Catalysis
• Asymmetric Synthesis

Background:

• Controlling enantioselectivity in radical reactions, particularly intermolecular ones, remains a significant challenge in organic synthesis.
• While intramolecular radical reactions have seen progress, intermolecular asymmetric induction is less developed.

Purpose of the Study:

• To develop a catalytic approach for controlling enantioselectivity and reactivity in intermolecular radical C-H amination.
• To enable efficient synthesis of chiral amino acid derivatives using readily available starting materials.

Main Methods:

• Utilized cobalt(II)-based metalloradical catalysis (MRC) for intermolecular C-H amination of carboxylic acid esters with organic azides.
• Employed a D2-symmetric chiral amidoporphyrin ligand with fine-tuned substituents to maximize noncovalent attractive interactions.

Main Results:

• Achieved high enantioselectivity and reactivity control in the intermolecular radical C-H amination.
• Demonstrated a broad substrate scope with high chemoselectivity under mild reaction conditions.
• Provided effective access to valuable chiral amino acid derivatives.

Conclusions:

• The developed noncovalent interaction strategy offers a general solution for controlling reactivity and enantioselectivity in intermolecular radical reactions.
• The Co(II)-catalyzed C-H amination proceeds via a stepwise radical pathway, offering insights into the catalytic mechanism.