Question

Final product (D) in the sequence of reaction is:

• A. 3-Methylbutan-1-ol
• B. 3-Methylpentan-1-ol
• C. 2-Methylpropan-1-ol
• D. Butan-1-ol

Answer 1

The correct option is A 3-Methylbutan-1-ol

Step-1 (Reaction with $PB{r}_3$):
Br substitutes OH. Hence, the product is $(C{H}_3{)}_{2}CHBr$

Step-2 (Reaction with Mg in the presence of dry ether):
Mg gets inserted between $(C{H}_3{)}_{2}CH$ and Br. Hence, the product is grignard reagent $\left(\right(C{H}_3{)}_{2}CHMgBr).$

Step-3 (Opening of epoxide and attacking of grignard reagent):
First, the $(C{H}_3{)}_{2}CHMgBr$ will break into $(C{H}_3{)}_{2}C{H}^{-}$ and $MgB{r}^{+}.$ Then, $MgB{r}^{+}$ will combine with oxygen of the epoxide and $CH(C{H}_3{)}_2^{-}$ will attack the epoxide ring and hence form $(C{H}_3{)}_{2}CH-C{H}_2-C{H}_2-OMgBr.$
Further, it underoges hydrolysis to form $1^o$ alcohol and $Mg\left(OH\right)Br$

The IUPAC name of product formed is 3-Methylpentan-1-ol.