Free radicals Flashcards
What types of conditions lead to free radical reactions?
Presence of AIBN (an initiator), ROOR, uv light, heat (300-500 degrees)
What is the trend in radical stability?
Allylic > Benzylic > 3,2,1 > methyl > vinyl/aryl
What are the stereochemical effects of free radical reactions?
Forms a nix of enantiomers BC the transition state is planar due to the p-orbital that contains the radical. This can be attack from either side.
What is the Hammond postulate and what does it tell us about endo vs exoteric reactions?
Hammond postulate: related species that are closer in energy are also closer in structure, and the structure of the transition state resembles the more stable species. Endothermic species are more selective because they have a transition state that is similar to their products. This gives them a greater difference in Ea to overcome if they choose to react with a less reactive carbon ie primary instead of secondary.
