σ-Bond insertion reactions of two strained diradicaloids.

Area of Science:

• Synthetic organic chemistry
• Medicinal chemistry
• Reaction methodology development

Background:

• Developing new synthetic methods is crucial for discovering novel medicines.
• Saturated arene bioisosteres are highly sought-after structural motifs in drug design.
• These bioisosteres often impart favorable drug-like properties, making them an active area of research.

Purpose of the Study:

• To report a new synthetic methodology for accessing the bicyclo[2.1.1]hexane scaffold.
• To demonstrate a method utilizing mild conditions and a simple protocol.
• To provide access to functionalized bicyclo[2.1.1]hexanes relevant for drug discovery.

Main Methods:

• The methodology involves the coupling of transiently generated cyclic allenes and bicyclo[1.1.0]butanes.
• These strained reactants possess significant strain energies, facilitating the reaction.
• The reaction is proposed to proceed via a diradical pathway, initiated by the innate diradicaloid character of the reactants, not external stimuli.

Main Results:

• A novel synthetic route to the bicyclo[2.1.1]hexane core structure was established.
• The reaction proceeds under mild conditions with an operationally simple protocol.
• The method successfully couples two highly strained fragments, cyclic allenes and bicyclo[1.1.0]butanes.

Conclusions:

• The developed method provides valuable access to functionalized bicyclo[2.1.1]hexanes for drug discovery.
• Geometric distortion in reactants can be strategically employed to enable unique reactivity, specifically diradicaloid pathways.
• This work encourages further exploration and application of diradicaloid chemistry in synthetic strategies.