Herein we disclose an iron‐catalyzed cross‐coupling reaction of propargyl ethers with Grignard reagents. The reaction was demonstrated to be stereospecific and allows for a facile preparation of optically active allenes via efficient chirality transfer. Various tri‐ and tetrasubstituted fluoroalkyl allenes can be obtained in good to excellent yields. In addition, an iron‐catalyzed cross‐coupling of Grignard reagents with α‐alkynyl oxetanes and tetrahydrofurans is disclosed herein, which constitutes a straightforward approach towards fully substituted β‐ or γ‐allenols, respectively.

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Palladium-metalated PCN-222 enables the aerobic photo-oxidative cross-condensation of anilines with benzylic amines yielding a series of linear and cyclic imines. The reaction is very efficient under mild conditions, which allows the isolation of simple, yet elusive, intermediates such as 2-(benzylideneamino)­aniline and 2-(benzylideneamino)­phenols. Recyclability studies show excellent activity and selectivity after five runs. The methodology was successfully applied for the synthesis of an antitumor agent (PMX-610).

1,4‐ and 1,5‐diols undergo cyclodehydration upon treatment with cationic N‐heterocyclic carbene (NHC)–IrIII complexes to give tetrahydrofurans and tetrahydropyrans, respectively. The mechanism was investigated, and a metal‐hydride‐driven pathway was proposed for all substrates, except for very electron‐rich ones. This contrasts with the well‐established classical pathways that involve nucleophilic substitution.

The mechanism of dehydrogenation of amines catalyzed by (cyclopentadienone)iron carbonyl complexes was studied by means of kinetic isotope effect (KIE) measurements, intermediate isolation, and density functional theory calculations. The (cyclopentadienone)iron–amine intermediates were isolated and characterized by 1H and 13C NMR spectroscopy as well as X-ray crystallography. The isolated iron–amine complexes are quite stable and undergo a formal β-hydride elimination to produce imine and iron hydride complexes. The KIEs observed for the iron-catalyzed dehydrogenation of 4-methoxy-N-(4-methylbenzyl)aniline are in accordance with stepwise dehydrogenation. The density functional calculations corroborate a stepwise mechanism involving a rate-determining hydride transfer from amine to iron to yield a metal hydride and an iminium intermediate, followed by a proton transfer from the iminium ion to the oxygen of the cyclopentadienone ligand.