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
Ibogamine is a naturally occurring iboga-type indole alkaloid found in Tabernanthe iboga and related species, and belongs to the same structural family as ibogaine, tabernanthine, and coronaridine. Like other iboga alkaloids, ibogamine has been studied for its psychoactive and potential … Read more
In this post, we will practice E2 elimination reactions, focusing on the mechanism and how to determine the major and minor products based on the structure of the substrate and the nature of the base. Common bases we will consider … Read more
In the previous post, we discussed ring expansion rearrangements where 4 and 5-membered rings were transformed into more stable, larger rings. Sometimes, the process goes in reverse direction, and larger rings are transformed into smaller rings. These are … Read more
Ring Strain and Ring Expansion The title of today’s discussion contains two keywords: Ring Expansion and Rearrangement. So, what are those? A ring expansion is the transformation of a smaller ring to a larger ring. A rearrangement is a change … 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
Before we start talking about naming bicyclic compounds, let’s first go over some terminology for their classification. Bicyclic compounds are a specific type of polycyclic compounds, classified as compounds that contain more than one ring with at least two common … 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
