Catalyst-dependent selectivity in sulfonium ylide cycloisomerization reactions

Area of Science:

• Organic Chemistry
• Catalysis
• Reaction Mechanisms

Background:

• Divergent catalysis allows synthesis of multiple compounds from a single starting material by varying reaction pathways.
• Controlling reaction pathways is key to achieving selectivity in organic synthesis.
• Sulfonium ylides are versatile synthetic intermediates.

Purpose of the Study:

• To investigate the role of π-acid catalysts in controlling the selectivity of alkene-tethered sulfonium ylide cycloisomerization.
• To elucidate the mechanism by which catalyst choice influences product distribution.
• To demonstrate an unusual example of catalyst-dependent divergent synthesis.

Main Methods:

• Cycloisomerization reactions of alkene-tethered sulfonium ylides using various π-acid catalysts.
• Computational mechanistic studies, including density functional theory (DFT) calculations.
• Analysis of reaction products to determine selectivity.

Main Results:

• Demonstrated catalyst-dependent selectivity in the cycloisomerization of sulfonium ylides.
• Identified specific π-acid catalysts that promote distinct reaction pathways.
• Computational studies revealed palladium's unique ability to cycle through oxidation states as crucial for selectivity control.

Conclusions:

• The choice of π-acid catalyst significantly impacts the outcome of sulfonium ylide cycloisomerization.
• Palladium catalysts offer unique advantages in controlling selectivity due to their redox properties.
• This work provides a foundation for developing new divergent catalytic strategies.