Isocyano Enones: Addition–Cyclization Cascade to Oxazoles

Copper iodide catalyzes the conjugate
addition of organometallic
and heteroatom nucleophiles to isocyano enones to afford oxazoles.
A range of enolates, metalated nitriles, amines, and thiols undergo
catalyzed conjugate addition to cyclic and acyclic oxoalkene isocyanides.
Mechanistic studies suggest that copper complexation facilitates the
nucleophilic attack on the isocyano enone to generate an enolate that
cyclizes onto the isocyanide leading to a variety of substituted acyclic
or ring-fused oxazoles.