Enantioselective Organophotocatalytic α-Functionalization of Aldehydes with N-Lactam Radicals: A Viable Strategy for the Telescoped Synthesis of Levetiracetam

The mild photocatalytic generation of N-lactam radicals is explored for the enantioselective α-functionalization of aldehydes in the presence of a chiral imidazolidinone organocatalyst. The reaction provides the desired products in high yields and up to 92% ee using a structurally simple, low-cost, and easy-to-prepare organocatalyst. The methodology was successfully applied to the telescoped synthesis of a pharmacologically relevant compound, (S)-levetiracetam, an antiepileptic drug.