Switching Chemoselectivity: Using Mechanochemistry to Alter Reaction Kinetics

Area of Science:

• Solid-state chemistry
• Organic synthesis
• Mechanochemistry

Background:

• Chemoselectivity is crucial for controlling reaction outcomes.
• Mechanochemistry offers unique reaction conditions distinct from traditional solution-phase chemistry.
• Controlling reaction pathways in mechanochemical processes remains an active area of research.

Purpose of the Study:

• To demonstrate that chemoselectivity can be altered by switching between neat milling and liquid assisted grinding (LAG).
• To investigate the mechanistic basis for the observed changes in reaction pathways.
• To establish mechanochemistry as a tool for trapping kinetic products.

Main Methods:

• Utilizing neat milling and liquid assisted grinding (LAG) with polar additives.
• Investigating reaction mechanisms through kinetic analysis.
• Comparing reaction outcomes under different mechanochemical conditions.

Main Results:

• A reaction manifold was discovered where chemoselectivity is tunable via milling conditions.
• The switching in reaction pathway was attributed to differing kinetics of a key transformation step under neat vs. LAG conditions.
• Proof of concept for using mechanochemistry to trap kinetic products was established.

Conclusions:

• Mechanochemical methods, specifically neat milling and LAG, can effectively control chemoselectivity.
• Understanding the kinetics of mechanochemical transformations is key to pathway control.
• This approach opens avenues for discovering novel synthetic processes and diverting known reaction pathways.