Solid-Phase Photochemical Decarboxylative Hydroalkylation of Peptides

Area of Science:

• Organic Chemistry
• Synthetic Chemistry
• Photochemistry

Background:

• Solid-phase peptide synthesis (SPPS) is a cornerstone of peptide research.
• Developing efficient methods for on-resin peptide modification is crucial for creating complex peptide structures.
• Photochemical reactions offer unique reactivity but their integration with SPPS remains challenging.

Purpose of the Study:

• To demonstrate the compatibility of photochemistry with solid-phase peptide synthesis.
• To establish a novel photochemical method for forming C(sp3)-C(sp3) bonds on solid support.
• To develop mild and efficient conditions for on-resin peptide modifications.

Main Methods:

• Photochemical hydroalkylation using iridium-based photocatalysts or Hantzsch ester.
• Reaction between on-resin Giese acceptors and redox-active esters.
• Optimization of reaction conditions including catalyst, solvent, and light source.

Main Results:

• Successful formation of C(sp3)-C(sp3) bonds on solid-phase peptides.
• High yields achieved using both iridium photocatalysts and Hantzsch ester.
• Full conversions obtained within 30 minutes under ambient conditions.
• Demonstrated compatibility with diverse peptide side chains, redox-active esters, and resins.

Conclusions:

• Photochemical hydroalkylation is a viable and efficient method for on-resin peptide modification.
• This work represents the first successful application of photochemistry for on-resin peptide modifications.
• The developed conditions are mild, rapid, and broadly applicable in peptide synthesis.