An unexpected inversion of enantioselectivity in the proline catalyzed intramolecular Baylis–Hillman reaction

Quantum Mechanical Investigations of Organocatalysis: Mechanisms, Reactivities, and Selectivities

“…74 In the presence of imidazole as co-catalyst, the enantioselectivity of the reaction improves considerably, but with an inversion of absolute configuration. Santos used DFT calculations to verify the mechanisms proposed by Hong.…”

Catalytic Asymmetric Baylis–Hillman Reactions and Surroundings

“…Hong and coworkers [89] investigated the intramolecular Baylis-Hillman reaction of hept-2-enedial by using a dual catalyst system (Scheme 10.76). A good enantioselectivity was obtained when using l-proline as catalyst, the most interesting phenomenon being that the configuration of the product was changed by the addition of imidazole to the reaction.…”

L-Proline catalyzed aldol reactions between acetone and aldehydes in supercritical fluids: An environmentally friendly reaction procedure

“…Since the pioneering work of List's group [1], L-proline and its derivatives as catalysts for the asymmetric aldol reaction between an aldehyde and a modified/unmodified acetone have received significant attention for the enantioselective CC bond formation [2,3]. It has been applied in Diels-Alder reactions [4], Baylis-Hillman reactions [5], Michael reaction [6], Mannich reaction [7], direct electrophilic R-aminations [8], Robinson annulations [9], aldol reactions, and others [10]. Among them, the direct aldol reaction is particularly of interest [11].…”