The use of microwaveheatingtechnique for the acceleration of ortho ester Claisen rearrangement (a three step transformation) is described. Irradiation of a DMF solution of the allyl alcohol , triethyl orthoacetate and propionic acid (catalytic) in an Erlenmeyer flask for 10 minutes in a microwave oven generated the ester in 83% yield. Analogously, ortho ester Claisen rearrangement of a variety of