Today's article from George is meant to wrap up the topic of small aliphatic rings, that we started in our Advent calendar posts (check those out, there are three great compound sets: Azetidine derivatives,  BCP derivatives, Oxetane derivatives).
Aliphatic three- and four-membered rings have been increasingly exploited in medicinal chemistry for their beneficial physicochemical properties and applications as functional group bioisosteres. The article we are mentioning covers the advantages of each ring system, potential hazards any significant chemical or metabolic stability, and toxicity risks.

The full text of the article is available here.

George also brought two more compound sets for you to finish up the collection:
  - Cyclopropanes compound set
  - Cyclobutanes compound set