In the following practice problems, we will discuss the mechanisms of pericyclic reactions, including electrocyclic reactions and cycloaddition reactions. We will use orbital symmetry to predict whether reactions proceed through ring opening or ring closure and practice identifying the stereochemistry … Read more
The main component of the stereochemistry of the Diels-Alder reaction that you are going to see in your class is the formation of endo and exo products when cyclic dienes react with dienophiles. The most common products in the reactions … Read more
We have seen that the product of the Diels-Alder reaction is most often a cyclohexene derivative. The ring is formed by the newly formed sigma bonds between the diene and the dienophile, which means 4 conjugated atoms combine with 2 … Read more
In this comprehensive set of practice problems, we will work through examples of Diels–Alder reactions that include both normal and retro Diels-Alder cases, as well as variations in regioselectivity and stereoselectivity. We will also look at endo and exo selectivity, … 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
Norbornane is a bicyclic compound (bicyclo[2.2.1]heptane) with a rigid, saturated framework. Norbornene is its corresponding alkene, containing a double bond that makes it reactive toward typical electrophilic addition reactions. Norbornanone is a ketone derivative, where the carbonyl group undergoes nucleophilic … Read more
In the previous post, we discussed ring expansion rearrangements where 4 and 5-membered rings were transformed into more stable, larger rings. Â Â Sometimes, the process goes in reverse direction, and larger rings are transformed into smaller rings. These are … Read more
Let’s compare the following two Diels-Alder reactions: The first one is a reaction between a symmetrical diene and a dienophile, and the second one is a reaction of an unsymmetrical diene and a dienophile.   What is interesting here … Read more
When a cyclic diene is used in the Diels-Alder reaction, a bridged bicyclic compound is formed: This looks ordinary until we draw the product from a side view, which reveals some nice structures and interesting features of the … Read more
In this post, we will discuss the reactivity and specifics of the diene and the dienophile in the Diels-Alder reaction. First, a reminder that the Diels-Alder reaction is a type of pericyclic reaction between a conjugated diene (two double bonds) … Read more
