Diarylprolinol with Trifluoromethyl Substituents and Diphenylprolinol‐Derived Perfluoroalkanesulfonamide as Organocatalysts in the Cross‐Aldol Reaction of Aldehydes.

The asymmetric cross‐aldol reaction of two different aldehydes is a synthetically relevant reaction. Diarylprolinol catalyst with trifluoromethyl substituents and sulfonamide catalyst derived from diphenylprolinol are organocatalysts for the cross‐aldol reaction. The reactivity and stereoselectivity of these two catalysts were compared in the asymmetric cross‐aldol reactions of propanal and acetaldehyde as nucleophilic aldehydes and several electrophilic aldehydes. Depending on the electrophilic aldehydes, the preferable catalyst differs. By the proper selection of these two catalysts, potentially synthetically useful chiral building blocks can be synthesized with diastereoselectivities of anti:syn=2.6:1∼>20:1 and enantioselectivities of 60∼>98% ee. [ABSTRACT FROM AUTHOR]