Stereo-reversed E2 unlocks Z-selective C-H functionalization.

Area of Science:

• Organic Chemistry
• Synthetic Chemistry
• Catalysis

Background:

• Stereoselective functionalization of C-H bonds is a significant challenge in organic synthesis.
• Existing C-H activation methods struggle with Z-selective alkene synthesis, especially for terminal alkenes.
• Selective cleavage of hindered C-H bonds in terminal alkenes remains difficult.

Purpose of the Study:

• To develop a novel method for Z-selective functionalization of alkenes.
• To overcome limitations in current C-H activation strategies for Z-alkene synthesis.
• To provide efficient access to Z-alkene targets from simple starting materials.

Main Methods:

• Transformation of alkenes into transient 1,2-bis-sulfonium intermediates.
• Utilizing paired electrolysis for selective generation and in situ elimination of bis-sulfonium intermediates.
• Employing Z-selective elimination of bis-sulfonium intermediates, challenging conventional E2 stereoselectivity.

Main Results:

• Successful Z-selective elimination of 1,2-bis-sulfonium intermediates was achieved.
• Paired electrolysis enabled efficient in situ generation and elimination of the intermediates.
• The method provides access to Z-alkenyl sulfonium linchpins, key precursors for Z-alkenes.
• The developed strategy offers a new route to diverse Z-alkene targets via cross-coupling.

Conclusions:

• A novel strategy for Z-selective alkene synthesis has been established.
• Paired electrolysis is identified as a key enabling technology for this transformation.
• The method offers a robust and efficient pathway to valuable Z-alkene compounds from readily available feedstocks.