Photo‐ and Cobalt‐Catalyzed Synthesis of Heterocycles via Cycloisomerization of Unactivated Olefins
Henry Lindner, Willi M. Amberg, Tristano C. Martini, David M. Fischer, Eléonore Moore, Erick M. Carreira
Abstract
We report a general, intramolecular cycloisomerization of unactivated olefins with pendant nucleophiles. The reaction proceeds under mild conditions and tolerates ethers, esters, protected amines, acetals, pyrazoles, carbamates, and arenes. It is amenable to N-, O-, as well as C-nucleophiles, yielding a number of different heterocycles including, but not limited to, pyrrolidines, piperidines, oxazolidinones, and lactones. Use of both a benzothiazinoquinoxaline as organophotocatalyst and a Co-salen catalyst obviates the need for stoichiometric oxidant or reductant. We showcase the utility of the protocol in late-stage drug diversification and synthesis of several small natural products.