The organo-alkali mechanism is supported by indirect evidence which shows that an organo-alkali intermediate actually forms during the reaction. This has been observed my many investigators. For example, ShoruguinSchoruigin: Ber. 41, 2711-7 (1908); ibid. 43, 1938-42 (1910). shows that carbon dioxide bubbling through a mixture of sodium and isobutyl bromide results in the formation of 3-methylbutanoic acid.
