The alkylidene malonates, alkylidene malonitriles, and alkylidene cyano acetates 3 were prepared by Knoevenagel condensation of an aldehyde and a doubly activated methylene compound 2 (malonate or malonitrile) (Scheme [1] ). When volatile aldehydes were used, a threefold excess was utilized. The Michael acceptors 3 were obtained in high yield (56-93%) after azeotropic removal of water during the reaction. [26] These were then subsequently treated with NBS in ...
