Electrogenerated Sm(II)-Catalyzed Carbon Dioxide Reduction for β-Hydrocarboxylation of Styrenes

Abstract

The synthesis of carboxylic acids from low-value materials such as alkenes using CO 2 as a C 1 -building block remains a real challenge for synthetic chemists from both reactivity and selectivity perspectives. Electrochemical carboxylations have been examined but they remain limited, still suffering from a crucial lack of selectivity. Herein we report a catalytic protocol based on an electrogenerated Sm(II) catalyst as a powerful CO 2 reductant, able to perform exclusively anti-Markovnikov hydrocarboxylation of alkenes. This electrochemical approach overcomes several current limitations and allows direct β-hydrocarboxylation of styrene derivatives, in a regioselective manner.

Alkyl Cyclopropyl Ketones in Catalytic Formal [3 + 2] Cycloadditions: The Role of SmI2 Catalyst Stabilization

“…Using “stoichiometric reagents” in a catalytic fashion is vital, as sustainability becomes the primary aspect of organic synthesis. , In this context, we have recently showcased the catalytic potential of SmI 2 , a reagent used in a superstoichiometric fashion for more than 50 years. − The use of SmI 2 in substoichiometric amounts not only reduces cost and waste but also has the potential to unveil reactivity paradigms that are hidden when excess SmI 2 is present. We have reported the first processes that operate solely with SmI 2 as a catalyst and do not require an excess of metal coreductants and additives (e.g., Mg and TMSCl) that compromises the atom economy gained by the move to catalysis. − Our mechanism-based approach to catalysis with SmI 2 hinges on the exploitation of radical relays; an electron is donated from and subsequently returned to the samarium center amid a series of bond-breaking and forming steps.…”