General method for iron-catalyzed multicomponent radical cascades-cross-couplings

Area of Science:

• Organic Chemistry
• Catalysis
• Synthetic Methodology

Background:

• Transition metal-catalyzed cross-coupling reactions are vital in chemical synthesis.
• Iron (Fe) offers advantages as a catalyst (cost, abundance, low toxicity) but has limited use in multicomponent cross-couplings.
• Previous methods have not successfully utilized iron for complex multicomponent couplings.

Purpose of the Study:

• To develop novel iron-catalyzed methods for multicomponent cross-coupling reactions.
• To enable the synthesis of cyclic fluorous compounds using iron catalysis.
• To expand the scope of radical cascade reactions catalyzed by iron.

Main Methods:

• Demonstration of 1,2-bis(dicyclohexylphosphino)ethane iron-catalyzed coupling of α-boryl radicals with Grignard reagents.
• Development of a general iron-catalyzed multicomponent annulation-cross-coupling protocol.
• Mechanistic studies involving Fe(II) species and alkyl radical intermediates.

Main Results:

• Successful iron-catalyzed coupling of α-boryl radicals and Grignard reagents.
• Broadly applicable protocol for multicomponent annulation-cross-coupling.
• Practical synthesis of diverse cyclic fluorous compounds achieved.
• Mechanistic insights into the catalytic cycle involving Fe(II) and alkyl radicals.

Conclusions:

• Iron catalysis can be effectively employed in complex multicomponent cross-coupling reactions.
• The developed protocol provides a practical route to cyclic fluorous compounds.
• This work expands the utility of iron as a catalyst in organic synthesis, particularly in radical-mediated transformations.