Branch-selective synthesis of oxindole and indene scaffolds: transition metal-controlled intramolecular aryl amidation leading to c3 reverse-prenylated oxindoles.

In an effort to access biologically important scaffolds, a concise branch-selective synthesis of C3 tertiary oxindoles by Cu(I)-catalyzed aryl amidation and 2,2-dimethyl indene by Pd(0)-catalyzed Heck cyclization has been accomplished from acyclic reverse-prenylated intermediates. Oxindole C3-enolate generation using NaH followed by alkylation in the presence of appropriate electrophiles provides a novel route to quaternary C3 reverse-prenylated oxindoles.