Kiliani-Fischer Synthesis

Carbohydrates

Lengthening aldoses by adding Cyanide, then reduing, finally oxidizing it to create a new aldehyde

Attacks aldoses - Creates epimers

• 1)5CSugar-C1OH -(HCN/KCN)-> 6CSugar-C1N
• 2)6CSugar-C1N -(Y))-> 6CSugar-C1H-NH
  • a-H2/(Pd/BaSO4
  • b-H3O
• 3)6CSugar-C1H-NH -(Z)-> 6CSugar-C1OH
  • a-H3O
  • b-NaHg

Mechanism:

• Two epimeric cyanohydrins leading to two epimeric aldoses
• H2/(Pd/BaSO4) isused to hydrogenate but not over reduce the cyanohydrin

Fundamentals:

Salient Examples:

Concepts:

Terminology:

Additional Information: