Divergent Reaction Pathways of beta-Chlorovinyl Ketones: Microwave-Assisted Thermal Nazarov Cyclization versus Cycloisomerization via Soft Vinyl Enolization

摘要

Divergent reaction pathways of beta-chlorovinyl ketones have been established to provide stereodefined alkylidenecyclopent-2-enones and 2-alkenylfuran derivatives. The switch of the reaction pathways was made possible by the microwave-assisted thermal Nazarov cyclization reaction of beta-chlorovinyl ketones, whereas the soft alpha-vinyl enolization of beta-chlorovinyl ketones allowed the generation of allenyl ketone intermediates that in turn smoothly underwent cycloisomerization to the 2-alkenyl furan derivatives in good to excellent yields.