Merging Halogen-Atom Transfer (XAT) and Cobalt Catalysis to Override E2-Selectivity in the Elimination of Alkyl Halides: A Mild Route toward contra-Thermodynamic Olefins

We report here a mechanistically distinct tactic to carry E2-type eliminations on alkyl halides. This strategy exploits the interplay of alpha-aminoalkyl radical-mediated halogen-atom transfer (XAT) with desaturative cobalt catalysis. The methodology is highyielding, tolerates many functionalities, and was used to access industrially relevant materials. In contrast to thermal E2 eliminations where unsymmetrical substrates give regioisomeric mixtures, this approach enables, by fine-tuning of the electronic and steric properties of the cobalt catalyst, to obtain high olefin positional selectivity. This unprecedented mechanistic feature has allowed access to contra-thermodynamic olefins, elusive by E2 eliminations.

Automated summary

An innovative strategy combining alpha-aminoalkyl radical-mediated halogen-atom transfer with desaturative cobalt catalysis allows for high olefin positional selectivity, providing access to contra-thermodynamic olefins. This approach, which can tolerate various functionalities and is high-yielding, offers a new pathway to industrially relevant materials.