Site-Selective Sequential Isocyanide Insertion at Dual sp3- and sp2-Carbon Centers Enables Divergent Access to N/O-Containing Heterocycles.

The study reports a Pd-catalyzed chemoselective sequential isocyanide insertion at sp3- and sp2-carbon centers, which enables the controlled incorporation of two or four isocyanide units. This cascade process, derived from readily accessible Passerini adducts, provides a divergent platform for the rapid assembly of diverse N- and O-containing heterocycles. The strategy overcomes the limitations of single-site reactions and offers high selectivity and structural complexity in heterocycle synthesis.