Q13P - Organic Chemistry (Mcmurry)

Question

How would you prepare the following diols?

Step-by-Step Solution

Answer

Answer

a) 

b) 

Step-by-Step Solution Step 1: Diols

Diols are compounds containing two hydroxyl groups (-OH). Trans-diols are formed by the opening of epoxides on reaction with aqueous acid. The C-OH and O-H bonds are formed, and the C-O bond is broken.

Step 2: The preparation of (a) compound

a. In the first step, the compound is reacted with OsO₄ , and pyridine. Both oxygens of OsO₄  approach from the same side of the alkene. In the second step, the reaction with OsNaHSO₃ , and H₂O , the break down of cyclic Os compound happens, and forms diols along with osmium salt are formed.

                                                 The formation of Diol

Step 3: The preparation of (b) compound

b. In the first step, 1-methylcyclohexene is reacted with peroxy acid and forms an epoxide ring. On further reaction with H₃O⁺, trans-1,2-diols are formed.

                                           The formation of Diol