Synergistic catalysis in asymmetric synthesis of polysubstituted pyrrolidines

This thesis deals with the feasibility of synthesizing stereodefined polysubstituted pyrrolidines in a formal [3+2] cycloaddition, starting with vinylciclopropanes (also called VCP) with two geminal electron-withdrawing groups (EWG), employed to make formal 1,3-dipole, and imines, used as dipolarophiles. This synthesis is based on the so called synergistic catalysis, that could be described as the combination of two catalytic species, each one able to activate one reaction partner. The former catalyst is a palladium complex, capable of activating the VCP by forming the aforementioned 1,3-dipole via oxidative addition. The latter, instead, is a chiral Brønsted acid, like a BINOL-derived phosphoric acid or triflamide, which not only makes the imine more electrophilic, but can also induce the preferential formation of a diastereoisomer over the other one and even enantiomeric excess within the diastereomeric couples, thanks to its axial chirality.