(Solved): Draw the curved-arrow mechanism for the acid-catalyzed ring-opening oligomerization (n = 3) of 2-eth ...

Draw the curved-arrow mechanism for the acid-catalyzed ring-opening oligomerization (n = 3) of 2-ethyloxirane. Draw the mechanism, intermediates, and product to show the same regioselectivity as acid-catalyzed, monomeric epoxide ring openings. In the first step, 2-ethyloxirane is treated with acid. The resulting compound reacts with another molecule of 2-ethyloxirane (step 2), and then another molecule of 2-ethyloxirane (step 3). Methanol is then added to terminate the polymerization (steps 4 and 5). When given the choice, draw the arrows that lead to the resonance structures with full octets around each atom other than hydrogen. Draw all atoms, electrons, and charges, if necessary, on all structures; do not show any inorganic byproducts or counterions. Reagents needed for each step are provided in the boxes. Ignore stereochemistry.