Synthesis of Enantiopure Bicyclic α,α-Disubstituted Spirolactams via Asymmetric Birch Reductive Alkylation

The synthesis of enantiopure bicyclic α,α-disubstituted spirolactams is described using a diastereoselective Birch reductive alkylation as the key step. Hydrogenation of the resultant alkylated cyclohexadienes followed by intramolecular cyclization provides access to enantiopure 8-azaspiro[5.6]dodecan-7-ones.