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Carbenes and nitrenes are versatile reactive intermediates that find widespread application in organic synthesis and drug discovery.[1] Their high reactivity, however,
often necessitates the use of metal complexes for stabilization of such species. Only recently, the photolysis of diazoalkanes, which are usually intensely colored, using
visible light attracted the interest of synthetic chemistry and many groups contributed to broaden applications of photochemical, catalyst-free carbene transfer eactions.[2,3]
These reactions most typically proceed via a singlet carbene intermediate. In the presence of a photocatalyst, however, new reaction pathways via redox chemistry or energy transfer can be opened-up.[2c]
In this context, we recently reported on the photocatalytic generation of triplet carbenes form diazoalkanes. This approach opens distinct pathways and does not
react along a classic singlet carbene reaction pathways, instead, e.g., gem- difluorolefination reactions can be accessed in the reaction with trifluoromethylated olefins or C-H functionalization with heterocycles.[4] In a related fashion, we could show that iodinanes can be used as simple, but versatile reagents, to access a nitrene or a nitrene radical anion under photochemical or photocatalytic conditions, respectively. These intermediates show a distinct reactivity in the reaction with olefins
and give either the product of C-H functionalization or aziridination.[5] |