Preparation of Amines
A variety of reactions that we have seen earlier can be used for preparing amines. The most straightforward would look like an SN2 reaction of an alkyl halide with ammonia or an amine: The main drawback of this … Read more
The only way of mastering any topic in Organic Chemistry is doing lots of practice problems. And I know, seeing my students, that starting to work on a practice problem may be the hardest part as you don’t know where to start. It is difficult to visualize what where the double bond would be moved if you follow the five curved arrows crammed in one step. Here is the trick:
We are always told to think before doing something. Fair enough. But let me tell you, it is also strangely enough, that in Organic Chemistry, it is often better to draw and then think about what you did (not in the lab though). It is much easier to have a structure in front of you and check for errors and improvements.
Do the first step, take the pencil and you will see that the ball gets rolling.
You have all these Organic Chemistry Practice Problems waiting to be solved!
A variety of reactions that we have seen earlier can be used for preparing amines. The most straightforward would look like an SN2 reaction of an alkyl halide with ammonia or an amine: The main drawback of this … Read more
In the previous post, we talked about the preparation of amines and one of the possible approaches was the direct SN2 reaction between an alkyl halide and a primary amine. The disadvantage of this method is the polyalkylation which occurs … Read more
We know that base-catalyzed halogenation of aldehydes and ketones replaces all the ɑ hydrogens: The reaction is difficult to stop at monohalogenation because the product, after the first step, is more reactive than the starting carbonyl, and therefore keeps … Read more
We talked about the Michael reaction in which the nucleophile is a doubly stabilized enolate performing a conjugate (1, 4) addition: Remember, at the same time, that regular enolates are not efficient Michael donors since they are stronger … Read more
A Claisen condensation between two different esters is called a crossed Claisen condensation. There are two main types of crossed Claisen that we will go over in this post. One is the reaction between esters, both having alpha hydrogens, and … Read more
Just like the aldol reaction, intramolecular Claisen reactions occur when five- or six-membered rings can be formed. These are called the Dieckmann condensation where one ester, of the same molecule, serves as an electrophile and the other is deprotonated and … Read more
We discussed quite extensively the aldol reactions of aldehydes and ketones, which involve enolate ions generated by base-catalysis. Esters are known to undergo an analog reaction called Claisen Condensation since they too have an acidic ɑ position to form an … Read more
In the previous post, we talked about the Michael reaction, which is a conjugate-addition reaction of doubly stabilized enolates such as malonic ester, acetoacetic ester, and the like with ɑ, β-unsaturated carbonyl compounds: One important variation of the … Read more
Michael reactions are conjugate-addition reactions of doubly stabilized enolates such as malonic ester, acetoacetic ester, and the like with ɑ, β-unsaturated carbonyl compounds: So, the Michael reaction is a particular type of conjugate addition reaction that ɑ, β-unsaturated … Read more
In the previous post, we talked about the acetoacetic ester synthesis, which is used for preparing ketones having one or two alkyl groups on the ɑ position: Another way to look at this reaction is to say that … Read more