Catalytic Stereoselective Borylative Transannular Reactions.

Area of Science:

• Organic Chemistry
• Catalysis
• Synthetic Methodology

Background:

• Medium-sized carbocycles are versatile scaffolds in organic synthesis.
• α,β-unsaturated ketones and internal ketones offer distinct reactivity sites.
• Developing efficient methods for constructing complex carbocyclic frameworks remains a challenge.

Purpose of the Study:

• To develop a novel Cu(I)-catalyzed reaction for transannular borylative ring closing.
• To control the relative stereochemistry of multiple stereocenters in the resulting polycyclic products.
• To achieve high enantioselectivity in the synthesis of complex carbocycles.

Main Methods:

• Utilized Cu(I)-catalyzed conjugated borylation of medium-sized carbocycles.
• Employed electrophilic intramolecular trapping following the borylation step.
• Investigated the use of chiral ligands to induce enantioselectivity.

Main Results:

• A pioneer transannular borylative ring closing reaction was established.
• The reaction demonstrated control over the relative configuration of three adjacent stereocenters, yielding single diastereoisomers.
• Enantiopure polycyclic products were obtained with up to 99% enantiomeric excess (ee) when using chiral ligands.

Conclusions:

• The developed methodology provides an efficient route to stereochemically defined polycyclic compounds.
• This copper-catalyzed reaction offers a powerful tool for accessing complex molecular architectures.
• The reaction's ability to control diastereoselectivity and enantioselectivity highlights its synthetic utility.