Hydrogen-Borrowing-Based Methods for the Construction of Quaternary Stereocentres

Area of Science:

• Organic Chemistry
• Synthetic Chemistry
• Stereoselective Synthesis

Background:

• Quaternary stereocenters are crucial structural elements in many biologically active molecules.
• Developing efficient synthetic routes to access these motifs is a significant challenge in organic chemistry.

Purpose of the Study:

• To develop a novel synthetic strategy for accessing alpha-quaternary ketones.
• To utilize the hydrogen borrowing manifold in a tandem acceptorless dehydrogenation-cyclisation cascade.
• To explore the formation of five- and six-membered carbocycles with high diastereoselectivity.

Main Methods:

• Employing a tandem acceptorless dehydrogenation-cyclisation cascade reaction.
• Utilizing the hydrogen borrowing manifold for C-C bond formation.
• Investigating the reaction mechanism and substrate scope.

Main Results:

• Successful synthesis of alpha-quaternary ketones via the described cascade reaction.
• Formation of five- and six-membered carbocycles with high diastereoselectivity.
• Observation of anomalous reactivity with benzylic alcohol substrates, leading to rearranged products.

Conclusions:

• The presented hydrogen borrowing strategy offers a new and efficient route to alpha-quaternary ketones.
• The tandem cascade reaction provides a powerful tool for constructing complex carbocyclic frameworks.
• Further investigation into the anomalous reactivity of benzylic alcohols may reveal new synthetic pathways.