(1R,2R)-DPEN-derived triazolium salts for enantioselective oxodiene Diels–Alder reactions

Enantioselective oxodiene Diels–Alder reactions catalyzed by (1R,2R)-DPEN-derived triazolium salts were realized successfully. With 0.5 mol % of (1R,2R)-DPEN-derived triazolium salt C and 150 mol % of Et3N, the reactions of various α-chloroaldehydes (α-bromoaldehyde) with substituted enones led to 3,4-dihydropyridinones and their derivatives in good yields, diastereoselectivities, and enantioselectivities (up to 97% ee).