Conformer-specific hydrogen atom tunnelling in trifluoromethylhydroxycarbene

Area of Science:

• Organic Chemistry
• Physical Chemistry
• Biomolecular Sciences

Background:

• Conformational control is crucial for organic reaction selectivity in biomolecular sciences.
• The Curtin-Hammett principle assumes facile equilibration between reactive conformers.
• Catalysts often select specific conformers for desired reactivity.

Purpose of the Study:

• To investigate the conformer-specific reactivity of trifluoromethylhydroxycarbene.
• To determine the applicability of the Curtin-Hammett principle to this system.
• To explore quantum mechanical effects in conformational control.

Main Methods:

• Computational analysis of trifluoromethylhydroxycarbene conformers.
• Investigation of reaction pathways including quantum mechanical tunneling.
• Comparison of cis and trans conformer reactivity.

Main Results:

• The trans conformer of trifluoromethylhydroxycarbene rearranges via hydrogen tunneling.
• The cis conformer of trifluoromethylhydroxycarbene is unreactive.
• A high energy barrier exists between the cis and trans conformers, invalidating the Curtin-Hammett principle.

Conclusions:

• This is the first observed instance of a conformer-specific hydrogen tunneling reaction.
• The Curtin-Hammett principle is not applicable when conformer interconversion is slow.
• Quantum mechanical hydrogen tunneling plays a significant role in the reactivity of specific conformers.