Verdugo Leal, Felipe IgnacioConcepción Vicente, Eduardo daRodiño Balboa, RicardoCalvelo Souto, MartínMascareñas Cid, José LuisLópez García, Fernando2020-07-242021-06-122020ACS Catal. 2020, 10, 14, 7710–7718http://hdl.handle.net/10347/23209This document is the Accepted Manuscript version of a Published Work that appeared in final form in ACS Catalysis, copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see https://doi.org/10.1021/acscatal.0c01827A 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 straightforward 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 tetrahydrofuran moieties (THFs) bearing trifluoromethyl–substituted carbonseng© 2020 American Chemical Society. This article may be used for non-commercial purposes in accordance with ACS Terms and Conditions for Use of Self-Archived VersionsPalladiumHydrocarbonsCyclizationKetonesCatalystsAlkylidenecyclopropaneCycloadditionjournal article10.1021/acscatal.0c018272155-5435open access