Fe/Thiol Cooperative Hydrogen Atom Transfer Olefin Hydrogenation: Mechanistic Insights That Inform Enantioselective Catalysis.

Asymmetric hydrogenation of activated olefins using transition metal catalysis is a powerful tool for the synthesis of complex molecules, but traditional metal catalysts have difficulty with enantioselective reduction of electron-neutral, electron-rich, and minimally functionalized olefins. Hydrogenation based on radical, metal-catalyzed hydrogen atom transfer (mHAT) mechanisms offers an outstanding opportunity to overcome these difficulties, enabling the mild reduction of these challenging olefins with selectivity that is complementary to traditional hydrogenations with H. Further, mHAT presents an opportunity for asymmetric induction through cooperative hydrogen atom transfer (cHAT) using chiral thiols.

HAT Lessons Help Hydrogen Hop, Skip, and Jump.

Nagib and Rajanbabu share a clever approach to remote desaturation triggered by metal-catalysed hydrogen atom transfer (mHAT) to an alkene, followed by intramolecular 1,6-HAT, and terminated via mHAT. This method both realizes a valuable synthetic transformation and provides multiple lessons for the design of HAT-mediated reactions.