Glucose→b)HI+Red P,1500ca)HCN/H2O A.  A is

Glucose →HCN CH2OH-CHOH4-CHOHCN ; CH2OH-CHOH4-CHOHCN →H2O CH2OH-CHOH4-CHOHCOOH; CH2OH-CHOH4-CHOHCOOH →HI+P/∆ CH3 -CH24-CH2-CH3;