A Catalytic Asymmetric Electrocyclization-Protonation Reaction

The first enantioselective Bronsted acid-catalyzed electrocyclization-protonation reaction has been developed which provides a number of different cyclopentenones in good yields and with high enantioselectivities. The stereodetermining step of this asymmetric Nazarov cyclization reaction is an asymmetric Bronsted acid-catalyzed kinetic protonation.