Correlation of electronic structure to iron catalyzed C-H bond functionalization In the field of homogenous catalysis, few reports have appeared offering general, chemically mild methods for the introduction of nitrogen- or oxygen-containing functional groups into simple hydrocarbon substrates. The ability to selectively incorporate functionality into unactivated C-H bonds represents a significant advance in converting inexpensive chemical feed stocks (e.g. hydrocarbons) to value-added functional molecules. However, the oxidative substitution of C-H bonds with amines or other functional groups often requires preoxidation of substrate or employs strong chemical oxidants in concert with atom or group transfer processes. A streamlined synthesis for functionalized products (e.g. N-heterocycles) with minimal or complete absence of waste generation would have tremendous impact on the synthesis of fine chemicals and pharmaceuticals. Towards this end, we have synthesized a class of electrophilic complexes featuring transiently-formed, or metastable metal-ligand multiple bonds capable of mediating C-H bond functionalization. Using dipyrrin ligand platforms as truncated models of the porphyrin platform found in P450 hydroxylase enzymes, we have observed reactivity from the ferrous-ligand constructs mirrors their porphyrin analogues. Catalytic C-H bond amination and olefin aziridination have been observed from the reaction of organic azides with simple iron(II) and iron(I) coordination complexes. The iron-catalyzed amination reaction is tolerant to a variety of organic azide precursors and has shown reactivity with a range of organic substrates to form N- heterocyclic products: linear azides can be intramolecularly aminated to form both pyrrolidine and piperidine structures, bearing an array of a-functional groups. The broader scientific impact of the proposed research can be summarized as the following: we will improve our understanding of factors contributing to the promotion of productive C-H bond activation and functionalization, further developing new classes of inorganic/organometallic catalysts to synthesize value-added commodity chemicals via clean reaction routes with minimal waste product.
The ability to selectively incorporate functionality into unactivated C-H bonds represents a significan advance in chemical synthesis. A streamlined synthesis for functionalized products (e.g. N-heterocycles) with minimal or complete absence of waste generation would have tremendous impact on the synthesis of fine chemicals and pharmaceuticals. We propose the selective synthesis of variable size N-heterocyclic complexes using iron- catalyzed nitrene group transfer protocols developed in our lab.
| Iovan, Diana A; Wilding, Matthew J T; Baek, Yunjung et al. (2017) Diastereoselective C-H Bond Amination for Disubstituted Pyrrolidines. Angew Chem Int Ed Engl 56:15599-15602 |
| Iovan, Diana A; Wrobel, Alexandra T; McClelland, Arthur A et al. (2017) Reactivity of a stable copper-dioxygen complex. Chem Commun (Camb) 53:10306-10309 |
| Kleinlein, Claudia; Bendelsmith, Andrew J; Zheng, Shao-Liang et al. (2017) C-H Activation from Iron(II)-Nitroxido Complexes. Angew Chem Int Ed Engl 56:12197-12201 |
| Kleinlein, Claudia; Zheng, Shao-Liang; Betley, Theodore A (2017) Ground State and Excited State Tuning in Ferric Dipyrrin Complexes Promoted by Ancillary Ligand Exchange. Inorg Chem 56:5892-5901 |
| Wilding, Matthew J T; Iovan, Diana A; Wrobel, Alexandra T et al. (2017) Direct Comparison of C-H Bond Amination Efficacy through Manipulation of Nitrogen-Valence Centered Redox: Imido versus Iminyl. J Am Chem Soc 139:14757-14766 |
| Wilding, Matthew J T; Iovan, Diana A; Betley, Theodore A (2017) High-Spin Iron Imido Complexes Competent for C-H Bond Amination. J Am Chem Soc 139:12043-12049 |
| Iovan, Diana A; Betley, Theodore A (2016) Characterization of Iron-Imido Species Relevant for N-Group Transfer Chemistry. J Am Chem Soc 138:1983-93 |
