Question

How would you convert an aldehyde to a ketone?

Answer 1

You have to add another carbon residue. A Grignard reaction followed by workup and oxidation would give a ketone.

Explanation:

`i. R-C(=O)H + R'-MgBr rarr RC(-OMgBr)R'`
`ii. R-CH(OMgBr)R' + H_2O rarr R-CH(OH)R' + MgBrOH`
`iii. R-CH(OH)R' + [O] rarr RC(=O)R'`

The electrophilic aldehyde will react with a Grignard or lithium reagent to give a new `C-C` bond and (after workup) a secondary alcohol. The secondary alcohol can be easily oxidized by various means to give a ketone.