Question

Write equations to show two different ways of converting iodomethane to ethanoic acid?

Answer 1

By either (i) carbonylation of the Grignard reagent; or (ii) reaction with cyanide, followed by acid hydrolysis.

Explanation:

Either scenario involves `C-C` bond formation. The Grignard route is probable the best way, and involves pouring an ethereal solution of the Grignard onto dry ice (here the dry ice is both a reactant, and cools the reaction down):

`H_3C-I + Mg rarr H_3C-MgI`

`H_3C-MgI + CO_2(s) rarr H_3C-C(=O)O^(-)MgI`

`H_3C-C(=O)O^(-)MgI + H^+"/"H_2O rarr H_3C-C(=O)OH + MgIOH`

Else:

`H_3C-I + KC-=N rarr H_3C-C-=N + KI`

`H_3C-C-=N +H^+ + H_2O + Deltararr H_3C-C(=O)OH + NH_2OH`