He W, Sun X, Frontier AJ. Polarizing the Nazarov Cyclization: Efficient Catalysis under Mild Conditions. JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 125: 12478-12479, 2003

Abstract Substituted divinyl ketones were studied in the Nazarov cyclization. α-Carbomethoxy divinyl ketones underwent efficient Nazarov cyclization with catalytic copper triflate (2 mol %) to give a single cyclopentenone regio- and stereoisomer. The efficiency of the cyclizations correlated with the ability of the substituents to favorably polarize the π-system of the cationic intermediate.......