Single-electron oxidation and α-deprotonation of tertiary anilines using Fe­(phen)3(PF6)3 afford α-aminoalkyl radicals, which can be coupled with electrophilic partners to afford various tetrahydroquinolines. Mechanistically, the Fe­(phen) n 2+/3+ catalytic cycle is maintained by O2 or a TBHP oxidant, and the presence of the oxygen bound iron complex, Fe­(III)–OO­(H), was elucidated by electron paramagnetic resonance and electrospray ionization mass spectrometry. This redox-selective nonheme iron catalyst behaves similarly to bioinspired heme iron catalysts.

An electron-transfer strategy using low-valent iron pentacarbonyl [Fe(CO)] to generate radical species from alkyl iodides was achieved. A range of pyrrolidines, tetrahydrofurans, and carbocycles were synthesized via 5-exo cyclization reactions of alkyl radical intermediates generated by electron transfer from a system involving Fe(CO), 1,10-phenanthroline, and diisopropylamine. Moreover, tandem addition reactions with Michael acceptors were also explored. Photophysical and electrochemical studies support a mechanism that involves electron transfer from the low-valent Fe reductant to alkyl iodide.

The synthesis of tetrahydroquinoline derivatives from dimethyl anilines and enamides has been developed by Fe(III)-phenanthroline complex under aerobic condition. The oxidation of tertiary anilines involving a single electron transfer of Fe(phen) 3 (PF 6 ) 3 afforded the iminium ion intermediate, which reacted with electron-rich alkenes to build a six-membered N-heterocycles containing quaternary carbon center via the oxidative Povarov reaction process.

Copper bromide was found to be an efficient catalyst for a domino reaction sequence leading to 3‐pyrrolines. The Cu(I)‐catalyzed Crabbé reaction of propargyl sulfonamide and selective cycloisomerization of the allene intermediate were carried out using microwave irradiation conditions affording a wide range of 2‐substituted‐ and 2,5‐disubstituted‐3‐pyrrolines. Mechanistic studies of the reaction intermediates revealed two possible reaction pathways; both invoke the importance of vinyl copper intermediates.

The Fe III (phen) 3 catalysis of the benzylic C(sp 3 )−H azidation of indoles has been investigated. The Fe(III) complex can selectively oxidize indoles to form arene radical cations, which are transformed into benzylic C(sp 3 ) radical intermediates. This strategy exhibits a difference in reactivity between N-heteroarenes and benzene, which is difficult to achieve via direct hydrogen abstraction approaches. Various biorelevant azide precursors were constructed, highlighting the utility of this mild first-row transition-metal catalyst system.