Carbenes and Nitrenes: Structure, Spin State and Reactions
Reactive Intermediates · Entrance Exams Carbenes and Nitrenes: Structure, Spin State and Reactions Whether a carbene adds to an alkene with retention or scrambles the stereochemistry is decided by one thing: singlet or triplet. BSc & MSc · Organic Chemistry · Concept The short answer: A carbene has six valence electrons on carbon and two non-bonding electrons that can be paired in one orbital or unpaired in two. Paired means singlet, and singlet carbenes add to alkenes in one step with complete retention of alkene geometry. Unpaired means triplet, which must react in two steps through a diradical, and rotation…