Synthesis of 3‑Carbonyl Trisubstituted Furans via Pd-Catalyzed Aerobic Cycloisomerization Reaction: Development and Mechanistic Studies

Herein, we report the synthesis of
3-carbonyl-trisubstituted furans
via Pd-catalyzed oxidative cycloisomerization reactions of 2-alkenyl-1,3-dicarbonyl
scaffolds, using molecular oxygen as the sole oxidant to regenerate
active palladium catalytic species, featuring good functional tolerance
and mild reaction conditions. Deep investigation of intermediates
and transition states of the reaction mechanism were conducted via
experimental and DFT studies, providing a detailed mechanistical profile.
The new developed methodology presents a greener alternative to Wacker-type
cycloisomerizations and avoids the use of stoichiometric amounts of
oxidants and strong acid additives.