Iron-Catalyzed C—H Insertions: Organometallic and Enzymatic Carbene Transfer Reactions

21 March 2018, Version 1
This content is a preprint and has not undergone peer review at the time of posting.


C—H insertion reactions with organometallic and enzymatic catalysts based on earth-abundant iron complexes remain one of the major challenges in organic synthesis. In this report, we describe the development and application of these iron-based catalysts in the reaction of two different carbene precursors with N-heterocycles for the first time. While FeTPPCl showed excellent reactivity in the Fe(III) state with diazoacetonitrile, the highest activities of the YfeX enzyme could be achieved upon heme-iron reduction to Fe(II) with both diazoacetonitrile and ethyl diazoacetate. This highlights unexpected and subtle differences in reactivity of both iron catalysts. Deuterium labeling studies indicated a C—H insertion pathway and a marked kinetic isotope effect. This transformation features mild reaction conditions, excellent yields or turnover numbers with broad functional group tolerance, including gram-scale applications giving a unique access to functionalized N-heterocycles.


C-H insertion
diazo compounds
biocatalytic process
flow chemistry

Supplementary materials



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