Compare the two methods shown for the preparation of carboxylic acids:

Mehod 1 : `RBr overset(Mg) underset("diethyl ether") rarr RMg Br overset(1.CO_2)underset(2.H_3O^+) rarr RCO_2H`
Method 2 : `RBr overset(NaCN) rarr RCN overset(H_2O,HCl)underset(heat) rarr RCO_2H`
Which one of the following statements correctly describes this conversion ?

Options

A. Both method 1 and method 2 are appropriate for carrying out this conversion
B. Neither method 1 nor method 2 is appropriate for carrying out this conversion
C. Method 1 will workwell, but method 2 is not appropriate
D. Method 2 will workwell, but method 1 is not appropriate

Answer

C

Explanation

At bridge head `S_(N_2)` doesn.t take place. According to bredt.s rule bridge head carbon can.t be `sp^2`-hybridized.
(Nal + Acetone) + R -X reaction `S_(N^2)` depends on
(1) Leaving group tendency is suitable preparation.
(2) Steric crowding .