Visible-Light-Induced Hydrosilylation Enabled by an In Situ Assembled Photoactive Complex

Area of Science:

• Organic Chemistry
• Photochemistry
• Radical Chemistry

Background:

• Traditional hydrosilylation often requires expensive or toxic photocatalysts and initiators.
• Visible-light photoredox catalysis has emerged as a powerful tool in organic synthesis.
• Developing catalyst-free or initiator-free visible-light-driven reactions is highly desirable for sustainable chemistry.

Purpose of the Study:

• To develop a photosensitizer-free, visible-light-driven protocol for hydrosilylation.
• To generate silicon-centered radicals in situ for synthetic applications.
• To explore the utility of these radicals in both hydrosilylation and dehalogenation reactions.

Main Methods:

• Mixing tris(trimethylsilyl)silane with cesium carbonate (Cs2CO3) to form a visible-light-absorbing species.
• Irradiation of the mixture at 456 nm to generate silicon-centered radicals.
• Reaction of the generated radicals with various alkenes and alkynes for hydrosilylation, and with halogenated compounds for dehalogenation.

Main Results:

• Successful generation of silicon-centered radicals upon visible-light irradiation without any exogenous photocatalyst.
• Efficient hydrosilylation of a diverse range of alkenes and alkynes using the generated radicals.
• Demonstration of the radicals' ability to act as halogen-atom transfer reagents for dehalogenation reactions.
• Elimination of the need for external initiators, photocatalysts, or HAT mediators.

Conclusions:

• A novel and efficient photosensitizer-free, visible-light-driven hydrosilylation reaction has been established.
• The developed method provides a sustainable alternative for silicon-centered radical generation and utilization.
• This strategy offers a simplified and more environmentally friendly approach to hydrosilylation and dehalogenation.