³Piperine can be synthesised by the selective formation of the (E)-a,b-unsaturated amide by an intermolecular three-component reaction between aldehydes, amines and ketenylidenetriphenylphosphorane (Ph3P=C=C=O). The reaction scheme is as follows: 

        Step 1 - stereoselective

       
        Step 3

       
        Step 4 - stereoselective