Thioetherification via Photoredox/Nickel Dual Catalysis

Area of Science:

• Organic Chemistry
• Photoredox Catalysis
• Organosilicon Chemistry

Background:

• Alkyl radicals are crucial intermediates in organic synthesis.
• Developing new precursors for radical generation under mild conditions is essential.
• Thioether synthesis is important for pharmaceuticals and materials science.

Purpose of the Study:

• To introduce hypervalent alkylsilicates as novel precursors for alkyl radicals.
• To develop a photoredox-mediated thioetherification reaction.
• To explore the scope and functional group tolerance of the new methodology.

Main Methods:

• Generation of alkyl radicals from hypervalent alkylsilicates using photoredox catalysis.
• Hydrogen atom abstraction from thiols by alkyl radicals to form thiyl radicals.
• Nickel-catalyzed cross-coupling of thiyl radicals with aromatic bromides.

Main Results:

• Successful generation of alkyl radicals from readily accessible hypervalent alkylsilicates.
• Demonstration of efficient S-H hydrogen atom abstraction from various thiols.
• Synthesis of diverse aryl and heteroaryl thioethers via nickel-catalyzed cross-coupling.
• High functional group tolerance, including protic moieties.

Conclusions:

• Hypervalent alkylsilicates are effective precursors for photoredox-generated alkyl radicals.
• A novel and versatile method for thioether synthesis has been established.
• The reaction tolerates a wide range of functional groups, highlighting its practical utility.