Question

Which of the following reactions will give optically inactive alcohol(s)?

• A.
• B.
• C.
• D.

Answer 1

Answer: (A), (D)

(a) $Os{O}_4$ does syn dihydroxylation. The products obtained are meso alcohols, so they are optically inactive.

(b) Cold dil. basic $KMn{O}_4$ does syn dihydroxylation of alkene. Due to absence of symmetry elements, product alcohols are optically active.

(c) Peracid after reaction with alkene produces epoxide, which upon hydrolysis gives diols.

(d) Due to centre of symmetry products obtained are optically inactive.