Compound 5 (shown below) displays intriguing reactivity features at distinct pHs. We will explore several examples. OH H 13 OH OH O LIOH 7 8 H. H2O H 5 6 pH 7 + CO2 HO OH O 10 (a) When 5 and 6 are treated with LIOH and the pH is further adjusted to highly basic (pH 13-14), products 7 and 8 are predominantly formed. Propose a reasonable mechanism for this reaction. OH OH LIOH H 13 O. H20 OH O 7 8 Hints: a somewhat challenging pathway; start with Aldol chemistry and recall the extreme pH! You may be able to "take advantage" of intramolecular H transfer. (b) When 5 and 6 are treated with LIOH and the pH is further adjusted close to neutral (pH 6-8), products 9 and 10 (in addition to CO2) are predominantly formed. Propose a reasonable mechanism for this reaction. OH OH OH LIOH pH 7 HO + CO2 H H20 H H OH OH O 5 9 10