Question

Identify the reagents (1-4), required for the transformation shown and arrange them in correct order.
(1) $LAH\left(LiAl{H}_4\right)$
(2) $Os{O}_4$
(3) $NaI{O}_4$
(4) $NaB{H}_4$

• A. $1\to 3\to 4\to 2$
• B. $2\to 3\to 1\to 4$
• C. $2\to 1\to 3\to 4$
• D. $1\to 2\to 3\to 4$

Answer 1

The correct option is D $1\to 2\to 3\to 4$

i) In step $1$ ${LiAH}_4$ reduces carbonyl groups into alcohol. It does not reduces double bond.

ii) $O_5{O}_4$ forms $1,2$ diol with double bond.

iii) ${NaIO}_4$ does cleavage of glycolic bond and form carbonyl group.

iv) In last step ${NaBH}_4$ reduces carbonyl group to alcohol.

Hence order of reaction of reagents are :-

$1\to 2\to 3\to 4$.