Photoredox-catalyzed multicomponent transformation towards functionalized trans-2,3-disubstituted indolines.

Area of Science:

• Organic Chemistry
• Catalysis
• Synthetic Methodology

Background:

• Multi-component reactions (MCRs) are valuable for efficient synthesis.
• Visible light photoredox catalysis offers sustainable synthetic routes.
• Indoline scaffolds are prevalent in pharmaceuticals and natural products.

Purpose of the Study:

• To develop an efficient visible light photoredox-catalyzed MCR for synthesizing functionalized trans-2,3-disubstituted indolines.
• To explore the use of diaryliodonium triflates and sulfonium/sulfoxonium ylides in this MCR.
• To establish the reaction mechanism and scope.

Main Methods:

• Visible light photoredox catalysis.
• Multi-component reaction (MCR) involving N-substituted 2-vinyl anilines, diaryliodonium triflates, and sulfonium/sulfoxonium ylides.
• Catalysis using Ru(bpy)3Cl2·6H2O or fluorescein.

Main Results:

• Efficient synthesis of diverse functionalized trans-2,3-disubstituted indolines in good to excellent yields.
• Demonstrated utility of both sulfonium and sulfoxonium ylides.
• Established radical intermediacy from diaryliodonium triflates and ylides.
• Broad substrate scope and high structural diversity achieved.

Conclusions:

• A novel and efficient visible light photoredox-catalyzed MCR for trans-2,3-disubstituted indoline synthesis has been developed.
• The reaction proceeds via a radical mechanism under mild and redox-neutral conditions.
• This methodology offers a versatile platform for accessing complex indoline derivatives.