Abstract:

A Pd catalyst made from a Pd(0) source and a bulky biaryl phosphine ligand promotes highly efficient intramolecular (3 + 2) heterocycloadditions between alkylidenecyclopropanes (ACPs) and carbonyls. The annulations provide a straightfor-ward access to fused polycyclic systems featuring β-methylene tetrahydrofuran moieties. DFT data support a pallada-ene process and shed light on the critical role of hemilabile interactions between the Pd center and the bulky biaryl phosphine. Significantly, these Pd(0) catalysts are also effective for promoting intermolecular formal cycloadditions between ACPs and trifluoromethyl ketones, thus providing for a direct entry to chiral THFs bearing trifluoromethyl–substituted carbons

External link: https://pubs.acs.org/doi/10.1021/acscatal.0c01827