Phthalimido-prolinamide: a new chiral catalyst for solvent free enantioselective aldol reactions

A new prolinamide derivative phthalimido-prolinamide 1 was developed for organocatalytic enantioselective direct aldol reactions of various aldehydes with ketones. The catalytic protocol is effective with 15 mol % of catalyst under solvent free and additive free reaction conditions. By employing a catalytic amount of water, the efficiency of the reaction increased further and the desired products β-hydroxy carbonyl compounds were obtained in high yields and stereoselectivities.

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(S)-tert-Butyl 2-(1,3-dioxoisoindolin-2-ylcarbamoyl)pyrrolidine-1-carboxylateC18H21N3O5[α]D25=-61.8 (c 0.85, CHCl3)Source of chirality: l-ProlineAbsolute configuration: (S)

(S)-N-(1,3-Dioxoisoindolin-2-yl)pyrrolidine-2-carboxamideC13H14N3O3[α]D25=-102.7 (c 1.89, CHCl3)Source of chirality: l-ProlineAbsolute configuration: (S)