Stereospecific positional alkene isomerization enables bidirectional central-to-axial chirality transfer

Area of Science:

• Organic Chemistry
• Catalysis
• Stereochemistry

Background:

• Positional alkene isomerization is a key reaction for C=C bond manipulation.
• High atom-economy and ease of handling make it valuable in organic and material chemistry.
• Stereospecific isomerization for bidirectional chirality transfer remains a significant challenge.

Purpose of the Study:

• To develop a method for bidirectional stereospecific positional alkene isomerization.
• To achieve central-to-axial chirality transfer using achiral Lewis base catalysis.
• To synthesize axially chiral N-indolylquinolinones with controlled configurations.

Main Methods:

• Utilized chiral exocyclic alkene analogues.
• Employed achiral Lewis base catalysis for isomerization.
• Investigated mechanistic pathways involving alkene isomerization and Michael/retro-Michael additions.
• Combined with asymmetric allylic substitution-isomerization and photocatalytic Z/E isomerization.

Main Results:

• Achieved bidirectional stereospecific positional alkene isomerization.
• Demonstrated successful central-to-axial chirality transfer.
• Synthesized axially chiral N-indolylquinolinones from one configuration to two different configurations.
• Obtained all eight stereoisomers of diaxially chiral quinolinones with high enantioselectivities and diastereselectivities.

Conclusions:

• The developed Lewis base catalysis enables efficient bidirectional stereospecific positional alkene isomerization.
• The central-to-axial chirality transfer strategy is effective for synthesizing diverse axially chiral compounds.
• The combination of methods provides access to all stereoisomers of complex chiral molecules.