Remember that when discussing crossed aldol reactions, we saw that they occur between two carbonyl compounds, one of which is first converted into a nucleophile through deprotonation at the α-position. The product is typically a β-hydroxy carbonyl compound, which can … Read more
We have seen that in the aldol condensation, the nucleophile is the alpha carbon that is activated in the form of an enolate. An interesting example of the aldol condensation is the crossed-aldol condensation, where one of the carbonyl compounds … Read more
Starting from General Chemistry and up until discussing the key principles of acids and bases, we recognize hydrogens connected to heteroatoms as being the acidic protons. Recall all the inorganic acids such as HCl, HBr, H₂SO₄, etc., and the carboxylic … Read more
We know that esters undergo different types of condensation reactions when their enolate are formed upon reacting with strong bases. The most common ones are the Claisen, Dieckmann, and also the crossed aldol condensation, where the enolate of the ester … Read more
The Favorskii rearrangement is a base-promoted skeletal rearrangement of α-halo ketones possessing at least one α-hydrogen. Treatment with base in the presence of a nucleophile (such as alcohols, amines, or water) results in a rearrangement via a cyclopropanone intermediate, ultimately … Read more
We have seen in the previous post that crossed aldol reactions allow us to prepare β-hydroxy carbonyl compounds by reacting an enolate (formed from one carbonyl compound) with another aldehyde or ketone, followed by protonation. A nice variation/type … Read more
In Knoevenagel condensation, we take a molecule where a methylene (CH2) is connected to (preferably) two electron-withdrawing groups, so we can deprotonate it and react with an aldehyde or a ketone. This allows the formation of a carbon-carbon double bond … Read more
Pethidine, also known as meperidine and marketed under the name Demerol, is a fully synthetic opioid of the phenylpiperidine class. Unlike morphine-based analgesics, its structure arises entirely from laboratory synthesis, making it a classic example of how multiple fundamental organic … Read more
When a beta hydroxy carbonyl compound is treated with a moderately strong base, such as a hydroxide or an alkoxide, an elimination occurs by expelling the hydroxyl group. The most common example is the aldol condensation reaction: So, … Read more
In this chapter on alpha carbon chemistry, you are going to come across the term “enol” almost in any new reaction. So, what is an enol? As the name suggests, these are species that contain an alkene (ene) and an … Read more
