Addition of LiAlH4 to ketones to give secondary alcohols
Description: Addition of lithium aluminum hydride to ketones leads to formation of secondary alcohols (after addition of acid) [private_ReactionGuide]
Notes: The precise identity of the acid is not generally important
Notes: Lots of different acids can be used in the last step. It’s not important which specific acid is used, just that something is present that can form the alcohol.
Mechanism: LiAlH4 is a source of hydride (H–) and the reaction begins with 1,2-addition of hydride to the carbonyl of the ketone (Step 1, arrows A and B). Upon addition of acid, the oxygen is protonated (Step 2, arrows C and D) to give the neutral alcohol.
Notes: The choice of H2O / H2SO4 as acid isn’t crucial here. Any strong acid will do.