The First Organocatalytic Hetero-Domino Knoevenagel-Diels-Alder-Epimerization Reactions: Diastereoselective Synthesis of Highly Substituted Spiro[cyclohexane-1,2′-indan]-1′,3′,4-triones - Ramachary, D B; Chowdari, Naidu S; Barbas III, Carlos F (Synlett, 2003)