Question

Orgo II Tutorial: Aldehyde and Ketone Reactions

Answer 1

\({\bf{Structures~and~Nomenclature:}}\) this is a very brief review; you are expected to know these from orgo I



aldehydes and ketones both contain the C=O carbonyl group which is typically given priority 1 since it's at the end of the molecule

to name an aldehyde, replace the ending -ane with -al
ex: propane --> propanal

to name a ketone, replace the ending -ane with -one
ex. butane --> butanone

if you need to name these groups as functional groups rather than compounds:

Answer 2

\({\bf{Physical~Properties:}}\)
- carbonyl group gives aldehydes and ketones higher BP's than their equivalent hydrocarbons
- unlike alcohols, aldehydes and ketones can not make hydrogen bonds so they have lower BP's than their equivalent alcohols
- the O on the C=O bond is electronegative and can form hydrogen bonds with water, making them soluble

Answer 3

\({\bf{Aldehyde~Synthesis:}}\) * the general pathway is alcohol --> aldehyde --> carboxylic acid *

- Swern Oxidation: will reduce a primary alcohol to an aldehyde.



- PCC and CH2Cl2 will achieve the same result

Answer 4

Ozonolysis of Alkenes: cleaves the double bond and adds an oxygen on either end



note the reactants and temperature for this one, they're quite particular about it

Answer 5

Reduction of Acyl Chlorides, Esters, and Nitriles:

* note: using LiAlH4 will NOT produce the desired aldehyde because it will keep reducing down to an alcohol. LiAlH4 is too powerful of a reducing agent *



instead, we will reduce the carboxylic acid into an acyl chloride, carboxylic acid, or an acyl chloride (we haven't studied this section yet but will probably go over it very soon)

we can use DIBAL-H OR Lithium tri-tert-butoxy-aluminum hydride, which are both derived from LiALH4 but aren't as strong reducing agents because of their steric hindrance





* in my textbook they prefer to use Lithium tri-tert-butoxy-aluminum hydride for acyl chloride reduction, at -78 degrees C with H2O, while for nitriles and esters they prefer to use DIBAL-H with water and hexane *

Answer 6

Anyway, that's the end of my tutorial, I hope it was a helpful resource. Source material is Organic Chemistry 12th edition by Solomons, et. al.