Discovery and development of ferrocene-based tetradentate ligands for Ir-catalysed asymmetric hydrogenation of ketone

The development of highly active and enantioselective ligands and catalysts for the asymmetric hydrogenation of ketone has been the goal of synthetic chemists for more than fifty years.Herein,a series of ferrocene-based tetradentate ligands were developed and applied in Ir-catalysed asymmetric hydrogenation of ketone.The hydrolytic ring-opening of the oxazoline moiety of ligand f-amphox leads to the accidental discovery of a highly efficient and enantioselective tetradentate ligand f-phamidol which showed extraordinarily high reactivity and enantioselectivity(up to 99%yield,up to>99%ee and up to 1,000,000 TON).In addition,two types of other tetradentate ligands f-phamida and f-phamide were also synthesized and evaluated.

Unusual Coordination Mode of Tetradentate Diiminedioxime Ligand in a Mononickel(Ⅱ) Complex:Synthesis, Characterization, and Computational Study

In this work, it is found that 1,8-dihydroxyimino-1,2,7,8-tetraphenyl-3,6-diazocta-2,6-diene(PhdoenH2) could react with nickel(Ⅱ) salt to yield a mononickel complex Ni(Phdoen)(1) with unusual [2N2O]-coordinated mode, while the analogous diimine-dioxime ligands usually form the [4N]-coordinated mode. The novel complex 1 has been carefully characterized by 1H NMR, elemental analysis, and X-ray diffraction structure analysis. The influences of the coordination modes on the structures and redox properties have been further investigated. Theoretical investigations revealed that the different coordination modes were ascribed to the thermodynamic properties of ligands.

Iron(Ⅱ) hydrides bearing a tetradentate PSNP ligand

A new class of iron（II） hydrides based on a tetradentate PSNP ligand were synthesized and fully characterized. All the iron（II） complexes feature a folded PSNP ligand with cis reactive sites. The hydrido iron complex [2 H（NCMe[2_TD$IF]1）]（BF4） is capable of catalyzing aldehyde hydroboration by pinacolborane（HBpin） and with extremely high efficiency at room temperature. Aldehydes with various functional groups are compatible.

Synthesis and characterization of a tetradentate PNCP iridium complex for catalytic alkane dehydrogenation

A novel hydrido iridium chloride complex supported by a tetradentate PNCP ligand has been synthesized and characterized. Upon activation with NaOtBu, the PNCP-IrHC1 complex is active for transfer dehydrogenation of cyclic and linear alkanes.

Nonheme Iron-Catalyzed Enantioselective cis-Dihydroxylation of Aliphatic Acrylates as Mimics of Rieske Dioxygenases

Enantioselective cis-dihydroxylation of alkenes represents an ideal route to synthesize enantioenriched syn-2,3-dihydroxy esters that are important structural motifs in numerous biologically and pharmaceutically relevant molecules.Bioinspired nonheme iron-catalyzed enantioselective cis-dihydroxylation meets the requirement of the modern synthetic chemistry from the atomic economy,green chemistry,and sustainable development perspectives.However,nonheme iron-catalyzed enantioselective cis-dihydroxylation is much underdeveloped because of the formidable challenges of controlling chemo-and enantioselectivities and product selectivity caused by the competitive epoxidation,cis-dihydroxylation,and overoxidation reactions.Herein,we disclose the fabrication of a biologically inspired nonheme iron complex-catalyzed enantioselective cis-dihydroxylation of multisubstituted acrylates using hydrogen peroxide(H_(2)O_(2))as the terminal oxidant by controlling the non-ligating or weakly ligating counterions of iron(Ⅱ)complexes,demonstrating a dramatic counteranion effect on the enantioselective cisdihydroxylation of olefins by H_(2)O_(2) catalyzed by nonheme iron complexes.A range of structurally disparate alkenes were transformed to the corresponding syn-2,3-dihydroxy esters in practically useful yields with exquisite chemo-and enantioselectivities(up to 99% ee).Given the mild and benign nature of this biologically inspired oxidation system as well as the ubiquity and synthetic utility of enantioenriched syn-2,3-dihydroxy esters as pharmaceuticals candidates and natural products,we expect that this strategy could serve as a promising complement to the well-known Sharpless asymmetric dihydroxylation,which is the chemical reaction of an alkene with OsO_(4) to produce a vicinal diol.