(Salen)Mn-catalyzed epoxidation of alkenes: a two-zone process with different spin-state channels as suggested by DFT study.

[structure: see text] A novel (two-zone process with different spin-state channels) mechanistic picture for the Jacobsen-Katsuki reaction is presented that provides insight into the still elusive understanding of the epoxidation mechanism. For the first time, we show that the salen moiety of the catalyst can be explicitly involved in the epoxidation process.