Polar-Radical Cyclization Cascades with Magnesiated Nitriles

Area of Science:

• Organic Chemistry
• Synthetic Chemistry
• Reaction Mechanisms

Background:

• Magnesiated nitriles are versatile synthons in organic chemistry.
• Radical cyclization reactions are key for forming cyclic structures.
• Developing efficient methods for synthesizing complex polycyclic ketones remains a challenge.

Purpose of the Study:

• To develop a novel synthetic route to bi- and tricyclic ketones.
• To explore the utility of a polar-radical addition-cyclization cascade.
• To investigate the combination of this cascade with carbonyl-conjugate addition for complex molecule synthesis.

Main Methods:

• Utilizing naphthalene as a single-electron oxidant.
• Employing magnesiated ω-alkenylnitriles as substrates.
• Performing a polar-radical addition-cyclization cascade followed by hydrolysis.
• Integrating a 1,2:1,4-carbonyl-conjugate addition with the cascade.

Main Results:

• Naphthalene effectively initiates a polar-radical cascade with magnesiated nitriles.
• The reaction generates diverse bicyclo[3.2.0]heptan-6-ones through a nitrile-stabilized radical pathway.
• Combining the cascade with conjugate addition yields complex cyclobutanones with four new C-C bonds and four chiral centers.
• The synthetic operation offers a streamlined approach to intricate molecular architectures.

Conclusions:

• The described polar-radical addition-cyclization cascade provides an efficient method for synthesizing bicyclic ketones.
• This strategy enables the rapid construction of complex cyclobutanones with high stereochemical control.
• The methodology holds significant potential for the synthesis of complex organic molecules and natural products.