The Fischer projection of the branched-chain carbohydrate D-apiose has been presented in Section 25.12.
(a) How many stereogenic centers are in the open-chain form of D-apiose?
(b) Does D-apiose form an optically active alditol on reduction?
(c) How many stereogenic centers are in the furanose forms of D-apiose?
(d) How many stereoisomeric furanose forms of D-apiose are possible? Write their Haworth formulas.