Switchable Chlorine Atom Transfer Radical Reactions.

A dual-copper relay strategy enables switchable chlorine atom transfer radical reactions from unactivated alkyl chlorides, switching between ATRA and ATRP-type pathways.

• Why it matters: Unactivated alkyl chlorides require cleaving stronger C–Cl bonds while preserving weaker ones in products, limiting atom transfer radical reactions.
• What they did: A dinuclear copper complex activates the robust C–Cl bond, while a mononuclear copper catalyst mediates controllable C–Cl bond reconstruction to switch pathways.
• The result: With or without the mononuclear copper partner, the protocol yields structurally diverse ATRA products, α-end-functionalized polyacrylates, and direct PVC modification under mild conditions.