Aerobic Pd-catalyzed sp3 C-H olefination: a route to both N-heterocyclic scaffolds and alkenes
Kara J Stowers1, Kevin C Fortner, Melanie S Sanford
1Department of Chemistry, University of Michigan, 930 North University Avenue, Ann Arbor, Michigan 48109, USA.
Abstract:
This communication describes a new method for the Pd/polyoxometalate-catalyzed aerobic olefination of unactivated sp(3) C-H bonds. Nitrogen heterocycles serve as directing groups, and air is used as the terminal oxidant. The products undergo reversible intramolecular Michael addition, which protects the monoalkenylated product from overfunctionalization. Hydrogenation of the Michael adducts provides access to bicyclic nitrogen-containing scaffolds that are prevalent in alkaloid natural products. Additionally, the cationic Michael adducts undergo facile elimination to release α,β-unsaturated olefins, which can be further elaborated via C-C and C-heteroatom bond-forming reactions.
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