Cobalt-Catalyzed Hydrofluorination of Unactivated Olefins: A Radical Approach of Fluorine Transfer

Catalytic hydrofluorination of olefins using a cobalt catalyst was developed. The exclusive Markovnikov selectivity, functional group tolerance, and scalability of this reaction make it an attractive protocol for the hydrofluorination of olefins. A preliminary mechanistic experiment showed the involvement of a radical intermediate

Direct Cyclization of Alkenyl Thioester via Transition Metal‐hydrogen Atom Transfer/radical‐polar Crossover Mechanism

We report here a catalytic, Markovnikov selective, and scalable synthetic method for the synthesis of saturated sulfur heterocycles, which are found in the structures of pharmaceuticals and natural products, in one step from an alkenyl thioester. Unlike a potentially labile alkenyl thiol, an alkenyl thioester is stable and easy to prepare. The powerful Co catalysis via a cobalt hydride hydrogen atom transfer and radical-polar crossover mechanism enabled simultaneous cyclization and deprotection. The substrate scope was expanded by the extensive optimization of the reaction conditions and tuning of the thioester unit.</div

Co-Catalyzed Hydroarylation of Unactivated Olefins

A mild, general, scalable, and functional group tolerant intramolecular hydroarylation of unactivated olefins using a Co­(salen) complex, a <i>N</i>-fluoropyridinium salt, and a disiloxane reagent was reported. This method, which was carried out at room temperature, afforded six-membered benzocyclic compounds from mono-, 1,1- or <i>trans</i>-1,2-di, and trisubstituted olefins

Hydroalkoxylation of Unactivated Olefins with Carbon Radicals and Carbocation Species as Key Intermediates

A unique Markovnikov hydroalkoxylation of unactivated olefins with a cobalt complex, silane, and <i>N</i>-fluoropyridinium salt is reported. Further optimization of reaction conditions yielded high functional group tolerance and versatility of alcoholic solvent employed, including methanol, <i>i</i>-propanol, and <i>t</i>-butanol. Use of trifluorotoluene as a solvent made the use of alcohol in stoichiometric amount possible. Mechanistic insight into this novel catalytic system is also discussed. Experimental results suggest that catalysis involves both carbon radical and carbocation intermediates

Hydroalkoxylation of Unactivated Olefins with Carbon Radicals and Carbocation Species as Key Intermediates

A unique Markovnikov hydroalkoxylation of unactivated olefins with a cobalt complex, silane, and <i>N</i>-fluoropyridinium salt is reported. Further optimization of reaction conditions yielded high functional group tolerance and versatility of alcoholic solvent employed, including methanol, <i>i</i>-propanol, and <i>t</i>-butanol. Use of trifluorotoluene as a solvent made the use of alcohol in stoichiometric amount possible. Mechanistic insight into this novel catalytic system is also discussed. Experimental results suggest that catalysis involves both carbon radical and carbocation intermediates

Catalytic Hydroamination of Unactivated Olefins Using a Co Catalyst for Complex Molecule Synthesis

Functional group tolerance is one of the important requirements for chemical reactions, especially for the synthesis of complex molecules. Herein, we report a mild, general, and functional group tolerant intramolecular hydroamination of unactivated olefins using a Co­(salen) complex, an <i>N</i>-fluoropyridinium salt, and a disiloxane reagent. This method, which was carried out at room temperature (or 0 °C), afforded three-, five-, six-, and seven-membered ring nitrogen-containing heterocyclic compounds and was compatible with diverse functional groups