Combined Effects on Selectivity in Fe-Catalyzed Methylene Oxidation

Abstract

Secondary Selectivity: Organic molecules consist principally of rings and chains of methylene (secondary) CH ₂ groups, intermittently adorned with oxygen or nitrogen centers and more heavily substituted carbons at the junctions. Synthetic transformations would be most efficient if the C–H bonds in any particular methylene group along the framework could be targeted for selective modification. However, for the most part, these carbon centers prove remarkably hard to differentiate for reactive purposes. Chen and White (p. 566 ) now show that an iron catalyst can direct peroxide to oxidize specific secondary C–H bonds preferentially, and with reasonable efficiency, in a range of complex molecules. The observed selectivities follow predictable trends correlated with the electronic and steric environment of the target site.