Redox III Video (Organic Chemistry)

[elisha98449]

In the Organic Chemistry Redox III video, it shows that to reduce a carboxylic acid to an aldehyde to use NaBH4 (sodium borohydride). However, I thought that sodium borohydride can only reduce carbonyls that are as reactive as ketones or more (i.e. not esters or amides). Reacting NaBH4 with the carboxylic acid seems like it would just deprotonate the carboxylic acid. Is this not correct?


Thanks.

[mcat_premed3832]

Yes, using NaBH4 will just make hydrogen gas and a salt of the carboxylic acid. So you are right that it will not reduce. In fact, here is a great summary of the reactions you are responsible for:

www.goldstandard-mcat.com/organic-chemistry-mechanisms/

But don't worry, the AAMC would not try a question to test if you memorized such a subtlety but good pick up.