6. The following procedure is part of a synthetic strategy for the enantioselective preparation of carbohydrates. Under these strongly basic conditions (NaOH), the alcohol group is deprotonated to give an alkoxide ion, which can then function as a strong nucleophile and participate in an intramolecular ring-opening reaction. This opens the epoxide ring but generates a new epoxide ring. Using this information, draw a complete mechanism for the conversion above and justify the stereochemical outcome.