Synthesis of Strained [gamma]-Lactams by Palladium(0)-Catalyzed C(sp3)-H Alkenylation and Application to Alkaloid Synthesis

A variety of strained [alpha]-alkylidene-[gamma]-lactams were synthesized by palladium(0)-catalyzed intramolecular C(sp3)-H alkenylation from easily accessible acyclic and monocyclic bromoalkene precursors. These lactams are valuable intermediates for accessing various classes of mono- and bicylic alkaloids containing a pyrrolidine ring, as illustrated with the synthesis of an advanced model of the marine natural product plakoridineA and of the indolizidine alkaloid [delta]-coniceine.