Use of isopropyl alcohol as a solvent in Ti(O-i-Pr)4-catalyzed Knöevenagel reactions

Knöevenagel reactions of aldehydes and ketones with malononitrile, isopropyl cyanoacetate and diisopropyl malonate catalyzed by Ti(O-i-Pr)4 proceeded smoothly in i-PrOH to give the corresponding reaction products in good to high yield. 3-Substituted coumarins were prepared by the present method.