Spirobicyclic diamines. Part 2: Synthesis of homochiral diastereoisomeric proline derived [4.4]-spirolactams

Reductive amination of homochiral primary amines ((R)- or (S)-α-methylbenzylamine, and (R)- or (S)-alanine methyl ester) with a racemic proline derived aldehyde, followed by cyclisation, gave diastereoisomeric [4.4]-spirolactams.