Direct aldol reactions catalyzed by 1,1,3,3-tetramethylguanidine lactate without solvent

The ionic liquid, 1,1,3,3-tetramethylguanidine lactate ([ TMG][Lac]), was used as a recyclable catalyst for direct aldol reactions at room temperature without any solvent. The results demonstrated that good chemo- and regio-selectivity could be achieved, and the ionic liquid can be easily recovered and recycled without considerable decrease of activity. The protocol is green and effective for producing beta-hydroxyl ketones.