So what have we learned about free radicals in this series? What Are Free Radicals? Free radicals are chemical species that contain a singly occupied orbital. They are neutral and tend to be highly reactive. One of the most common classes of free-radical reactions is free-radical substitution. Here … [Read more...]
Bonus Topic: Allylic Rearrangements
In this series on free radical reactions we've mostly covered the basics. In this post (and the next one) we're going to go into a little bit more detail on certain topics that until now I haven't had time to dive into. Today's topic flows right from the subject of the last post, on allylic … [Read more...]
Allylic Bromination
In previous posts on radicals, we've seen how bromine can selectively react with tertiary C-H bonds (bond strength 93 kcal/mol) over secondary (96 kcal/mol) and primary (100 kcal/mol) C–H bonds. If you recall that bond dissociation energies are a good guide for predicting radical stability, then … [Read more...]
Reagent Friday: NBS (N-Bromo Succinimide)
In a blatant plug for the Reagent Guide, each Friday I profile a different reagent that is commonly encountered in Org 1/ Org 2. If you've ever had the "pleasure" of working with bromine (Br2), you'll know that this dense orange liquid is a pain in the butt for two reasons. First of all, it … [Read more...]