Palladium-Catalyzed Tandem Cycloisomerization/Cross-Coupling of Carbonyl- and Imine-Tethered Alkylidenecyclopropanes

Angew Chem Int Ed Engl. 2022 Jun 13;61(24):e202202295. doi: 10.1002/anie.202202295. Epub 2022 Apr 14.

Abstract

Pd0 catalysts featuring phosphorus-based monodentate ligands can detour the reactivity of carbonyl-tethered alkylidenecyclopropanes (ACPs) from standard (3+2) cycloadditions towards tandem cycloisomerization/cross-coupling processes. This new reactivity lies on the formation of key π-allyl oxapalladacyclic intermediates, which are subsequently trapped with external nucleophilic partners, instead of undergoing canonical C-O reductive eliminations. Importantly, the use of imine-tethered ACP's is also feasible. Therefore, the method provides a straightforward and stereoselective entry to a wide variety of highly functionalized cyclic alcohols and amines.

Keywords: Alkylidenecyclopropanes; Boronic Acids; Cycloisomerization; Palladium Catalysis; Tandem Reaction.