Solution: Provide a reasonable mechanism for the transformation below. Hint: This occurs in three steps, all of which are Lewis Acid/Base reactions. Fill in the missing intermediates A and B. Be sure to provide the arrows to show electron flow.

Problem

Provide a reasonable mechanism for the transformation below. Hint: This occurs in three steps, all of which are Lewis Acid/Base reactions. Fill in the missing intermediates A and B. Be sure to provide the arrows to show electron flow.