Based on a "transition metal frustrated Lewis pair" approach, a cyclopentadienone iron tricarbonyl complex has been designed and applied in the reductive amination and hydrogenation of bicarbonate. This well-defined phosphine-free complex displays the best activities reported to date for an iron complex in the reduction of bicarbonate into formate and in reductive amination.

A domino desulfitative coupling/acylation/hydration process to synthesize C‐2‐(2‐oxo‐2‐phenylethylidene)‐ and N‐3‐carbonyl‐substituted pyrimidines by unprecedented CC and CN cross‐coupling reactions is described. This methodology couples 3,4‐dihydropyrimidine‐2‐thiones and alkynes under modified Liebeskind–Srogl conditions using palladium acetate and copper(I) carboxylate. Remarkably the copper(I) carboxylates simultaneously act as desulfitative and acylation reagents in the reaction.

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A transition-metal frustrated Lewis pair approach has been envisaged to enhance the catalytic activity of tricarbonyl phosphine-free iron complexes in reduction of amines. A new cyclopentadienyl iron­(II) tricarbonyl complex has been isolated, fully characterized, and applied in hydrogenation. This phosphine-free iron complex is the first Earth-abundant metal complex that is able to catalyze chemoselective reductive alkylation of various functionalized amines with functionalized aldehydes. Such selectivity and functionality tolerance (alkenes, esters, ketones, acetals, unprotected hydroxyl groups, and phosphines) have been demonstrated also for the first time at room temperature with an Earth-abundant metal complex. This alkylation reaction was also performed without any preliminary condensation and generated only water as a byproduct. The resulting amines provided rapid access to potential building blocks, metal ligands, or drugs. Density functional theory calculations highlighted first that the formation of the 16 electron species, via the activation of the tricarbonyl complex Fe3, was facilitated and, second, that the hydrogen cleavage did not follow the same pathway as bond breaking, usually described with the known cyclopentadienone iron tricarbonyl complexes (Fe1 and Fe4). These calculations highlighted that the new complex Fe3 does not behave as a bifunctional catalyst, in contrast to its former congeners.

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The [Ni(0)(cod) 2 ]/P ∩ P-catalyzed hydroalkoxylation of butadiene to form butenyl ethers is studied mechanistically, where P ∩ P = 1,4bis(diphenylphosphino)butane (dppb) and 1,2-bis(diphenylphosphinomethyl)benzene (dppmb). Experimental studies suggest the intermediacy of [(P ∩ P)-Ni(0)(butadiene)] and [(P ∩ P)Ni(II)(allyl)] intermediates and rule out the involvement of Ni−H species. The related species [(dppb)Ni(0)(1,4diphenylbutadiene)], 1, and [(P ∩ P)Ni(II)(crotyl)(Cl)] complexes 2 (P ∩ P = dppmb) and 3 (P ∩ P = dppb) have been synthesized and characterized on the basis of VT NMR spectroscopy and X-ray crystallographic studies. Compounds 2 and 3 are shown to be catalytically competent for the hydroalkoxylation reaction. Computational studies on [(dppmb)Ni(0)(butadiene)] indicate a facile protonation that forms a cationic allylic intermediate [(dppmb)Ni(II)(η-C 4 H 7 )]OMe. C−O bond formation then occurs via external attack by the solvent-stabilized methoxide nucleophile.Hydroalkoxylation proceeds with modest computed barriers of ca. 18 kcal/mol, and the butenyl ether product formation is only marginally exergonic. Overall, the results are consistent with initial kinetic control leading to the major branched isomer followed by a reversible isomerization process operating under thermodynamic control.

We report a new, simple and air-stable iron(II) complex pre-catalyst for the synthesis of substituted pyridines via a [2+2+2] cycloaddition between diynes and nitrile derivatives.

The newly developed title complex proves efficient in the reductive amination of various aldehydes and ketones with primary aliphatic and aromatic amines as well as secondary amines.