Question

What two aldohexoses yield d-arabinose upon Wohl degradation?

Short answer

Answer

Step-by-step solution

Wohl degradation

Wohl degradation is an important reaction in carbohydrate chemistry. This reaction shortens the carbon chain in a stepwise manner by cleaving the bond of the aldose chain.

From D-glucose

D-glucose is treated with ${\mathrm{NH}}_2\mathrm{OH},{\mathrm{AC}}_2\mathrm{O}$ gives a cyanohydrin further react with ${\mathrm{NaOCH}}_3$ form D-arabinose.

Formation of D-arabinose from D-glucose

From D-mannose

D-mannose is treated with ${\mathrm{NH}}_2\mathrm{OH},{\mathrm{Ac}}_2\mathrm{O},\mathrm{AcONa},\mathrm{AcOH}$forms a product with on further reaction with ${\mathrm{NaOCH}}_3$form D-arabinose.

Formation of D-arabinose from D-mannose