Melphalan, a drug used in chemotherapy, reacts with itself in the body before binding with its target, as illustrated in the mechanisr below. Which two patterns of arrow pushing are seen in this reaction? I. proton transfer II. loss of leaving group III. nucleophilic attack IV. rearrangement Indicate which pattern of arrow pushing it is involved in the reaction step shown. proton transfer loss of leaving group nucleophilic attack rearrangement Which of the structures shown is the most stable cation? Which of the structures shown cannot be a nucleophile? Identify the electrophilic site in the molecule shown. a