Computation-Guided Development of the "Click" ortho-Quinone Methide Cycloaddition with Improved Kinetics

Area of Science:

• Organic chemistry
• Chemical biology
• Reaction mechanisms

Background:

• Click chemistry offers efficient molecular ligation.
• Ortho-quinone methides (oQMs) are reactive intermediates for cycloadditions.
• Protein labeling requires efficient and specific chemical reactions.

Purpose of the Study:

• To elucidate the mechanism of the "click" ortho-quinone methide (oQM) cycloaddition.
• To develop an improved oQM cycloaddition for protein labeling applications.

Main Methods:

• Density Functional Theory (DFT) calculations were employed to study the reaction mechanism.
• Synthesis and testing of novel ortho-quinolinone quinone methide (oQQM) precursors were performed.

Main Results:

• DFT calculations identified dehydration of oQQM precursors as the rate-determining step.
• Two highly reactive oQQM precursors were computationally predicted.
• A new "click" oQM cycloaddition with improved kinetics and efficiency was developed.

Conclusions:

• The rate-determining step in TQ-ligation is the dehydration of oQQM precursors.
• Computational predictions guided the development of a more efficient oQM cycloaddition.
• The developed method demonstrates remarkable efficiency for protein labeling.