Chiral Bicyclic Lactams for Asymmetric Synthesis of Quaternary Carbons. The Total Synthesis of (-)-α-Cuparenone

Article abstract of DOI:10.1021/jo00359a030

An asymmetric synthesis of the title compounds has been achieved in >98percent ee using chiral bicyclic lactams 14 derived from (S)-valinol and γ-keto acids.Thus, cyclocondensation of racemic 2-p-tolyl-4-oxopentanoic acid with (S)-valinol gave a 1:1 mixtu