Give chemical reactions to show the action of CO2 & ethanal on methyl magnesium bromide and methyl lithium?

1 Answer
Oct 25, 2015

The metal reagent and carbon dioxide gives a carboxylate salt (a carboxylic acid on work up). With acetaldehyde, a secondary alcohol results.

Explanation:

In fact one of the best ways of making a carboxylic acid is by pouring the Grignard mixture onto dry ice:

RMgX+CO2RC(=O)O(MgX)+;
RC(=O)O(MgX)++HXRCO2H+MgX2

The reaction would also occur with methyl lithium.

With acetaldehyde or ethanal, H3CC(=O)H, CC bond formation again occurs and a isopropanol will result after workup:

H3CC(=O)H+LiCH3H3CC(OLi+)CH3
H3CCH(OLi+)CH3+HXH3CCH(OH)CH3+LiX

Note that CC bond forming reactions are exceptionally rare, which is why the utility of these reactions is stressed in undergraduate studies.