(a) E-Hex-2-enal is the alarm pheromone of the myrmicine species of ants. It can be synthesized based on the pathway highlighted below. Na n-Bull POC - PPh 12 E OH H-CEC-L (1 Equiv) H NH3 C=0 H (i) Deduce the structures of the missing intermediate compounds (E-H) in this synthesis and of pheromone I. (2 Marks each). Propose a retrosynthetic pathway for the pheromone that is consistent with synthetic scheme above. (4 Marks)