Highly Efficient and Reusable Dendritic Catalysts Derived fromN-Prolylsulfonamide for the Asymmetric Direct Aldol Reaction in Water

Abstract

The direct aldol reactions catalyzed by chiral dendritic catalysts derived from N-prolylsulfonamide gave the corresponding products in high isolated yields (up to 99%) with excellent anti diastereoselectivities (up to >99:1) and enantioselectivities (up to >99% ee) in water. In addition, catalyst 1e may be recovered by precipitation and filtration and reused for at least five times without loss of catalytic activity.

Asymmetric Organocatalysis

“…More importantly, the catalyst could be recovered and reused for six times with maintained stereoselectivity. Wang and co-workers have synthesized various dendritic catalysts derived from N-prolylsulfonamide for the direct aldol reaction of cyclohexanone [21]. The dendritic catalyst could be recovered and reused at least five times without loss of catalytic activity and stereoselectivity.…”

Using Soluble Polymer Supports To Facilitate Homogeneous Catalysis

“…131 Using the reaction shown in eq 84, the dendritic catalysts 77a, 77b, and 77c were compared one to another and to a low molecular weight N-prolylsulfonamide.…”

An efficient RuIII/BINAP catalytic system for the aldol reactions of ketones with various aldehydes

“…Barbas discovered that L-proline may be used as the catalyst for the direct asymmetric aldol reaction, 8 many groups have developed various proline-based organocatalysts [9][10][11][12][13][14][15] for the direct asymmetric aldol reaction. Among them, N-terminal prolyl dipeptides are effective for the direct catalytic asymmetric aldol reaction.…”