Iron(III) Chloride-Catalysed Aerobic Reduction of Olefins using Aqueous Hydrazine at Ambient Temperature

Iron-Catalyzed Transfer Hydrogenation of Allylic Alcohols with Isopropanol

Herein, we report an iron-catalyzed transfer hydrogenation of allylic alcohols. The operationally simple protocol employs a well-defined bench stable (cyclopentadienone)iron(0) carbonyl complex as a precatalyst in combination with K2CO3 (4 mol %) and isopropanol as the hydrogen donor. A diverse range of allylic alcohols undergo transfer hydrogenation to form the corresponding alcohols in good yields (33 examples, ≤83% isolated yield). The scope and limitations of the method have been investigated, and experiments that shed light on the reaction mechanism have been conducted.

Hydrazine Hydrate Accelerates Neocuproine-Copper Complex Generation and Utilization in Alkyne Reduction, a Significant Supplement Method for Catalytic Hydrogenation

Diimine (HN═NH) is a strong reducing agent, but the efficiency of diimine oxidized from hydrazine hydrate or its derivatives is still not good enough. Herein, we report an in situ neocuproine-copper complex formation method. The redox potential of this complex enable it can serve as an ideal redox catalyst in the synthesis of diimine by oxidation of hydrazine hydrate, and we successfully applied this technique in the reduction of alkynes. This reduction method displays a broad functional group tolerance and substrate adaptability as well as the advantages of safety and high efficiency. Especially, nitro, benzyl, boc, and sulfur containing alkynes can be reduced to the corresponding alkanes directly, which provides a useful complementary method to traditional catalytic hydrogenation. Besides, we applied this method in the preparation of the Alzheimer's disease drug CT-1812 and studied the mechanism.

Organic synthesis with the most abundant transition metal–iron: from rust to multitasking catalysts

The promising aspects of iron in synthetic chemistry are being explored for three-four decades as a green and eco-friendly alternative to late transition metals. This present review unveils these rich iron-chemistry towards different transformations.

Chemoenzymatic Cascade Synthesis of Optically Pure Alkanoic Acids by Using Engineered Arylmalonate Decarboxylase Variants

Arylmalonate decarboxylase (AMDase) catalyzes the cofactor‐free asymmetric decarboxylation of prochiral arylmalonic acids and produces the corresponding monoacids with rigorous R selectivity. Alteration of catalytic cysteine residues and of the hydrophobic environment in the active site by protein engineering has previously resulted in the generation of variants with opposite enantioselectivity and improved catalytic performance. The substrate spectrum of AMDase allows it to catalyze the asymmetric decarboxylation of small methylvinylmalonic acid derivatives, implying the possibility to produce short‐chain 2‐methylalkanoic acids with high optical purity after reduction of the nonactivated C=C double bond. Use of diimide as the reductant proved to be a simple strategy to avoid racemization of the stereocenter during reduction. The developed chemoenzymatic sequential cascade with use of R‐ and S‐selective AMDase variants produced optically pure short‐chain 2‐methylalkanoic acids in moderate to full conversion and gave both enantiomers in excellent enantiopurity (up to 83 % isolated yield and 98 % ee).

An efficient and sustainable catalytic reduction of carbon–carbon multiple bonds, aldehydes, and ketones using a Cu nanoparticle decorated metal organic framework

Economical, reusable, eco-friendly sustainable process is reported that involve low amount of hydrazine hydrate.

An efficient halometallate ionic liquid functionalized mesoporous ZSM-5 for the reduction of carbon–carbon multiple bonds

Bi-functional activity and highly dispersed active sites present in halometallate ionic liquid functionalized mesoporous ZSM-5 makes it a unique and superior catalyst compared to various other catalysts reported in the literature.

A Serendipitous Rendezvous with a Four-Center Two-Electron Bonded Intermediate in the Aerial Oxidation of Hydrazine

Oxidation by dioxygen has a rich repertoire of mechanistic intricacies. Herein, we report a hitherto unknown paradigm of dioxygen activation reaction which propagates through a four center two electron (4c-2e) bound species. Using static DFT and ab initio quantum chemical techniques we have unraveled the oxidation pathway for hydrazine and its methylated analogues by dioxygen which involves formation of this unconventional 4c-2e bonded species en route to the oxidation products. Inconvertible evidence in favor of such an unprecedented dioxygen activation route is provided by capturing the events of formation of the 4c-2e species in aqueous phase for hydrazine and its congeners and the experimentally observed products from the respective 4c-2e species, like H2O2 and N2H2 , diazene in the case of hydrazine using Car-Parrinello molecular dynamics simulations.

In tandem or alone: a remarkably selective transfer hydrogenation of alkenes catalyzed by ruthenium olefin metathesis catalysts

A remarkably selective system for transfer hydrogenation of alkenes, composed of Grubbs’ ruthenium metathesis catalyst and HCOONa/HCOOH, is presented. This system can also be formed directly after a metathesis reaction to effect hydrogenation in a single-pot.

Trinuclear {Co2+–M3+–Co2+} complexes catalyze reduction of nitro compounds

Trinuclear {Co²⁺–Co³⁺–Co²⁺} and {Co²⁺–Fe³⁺–Co²⁺} complexes function as reusable heterogeneous catalysts for the selective reduction of assorted nitro compounds to their corresponding amines. The mechanistic investigations suggest the involvement of a Co(ii)–Co(i) cycle in the catalysis.

Total synthesis of (R,R,R)-γ-tocopherol through Cu-catalyzed asymmetric 1,2-addition

Based on the asymmetric copper-catalyzed 1,2-addition of Grignard reagents to ketones, (R,R,R)-γ-tocopherol has been synthesized in 36 % yield over 12 steps (longest linear sequence). The chiral center in the chroman ring was constructed with 73 % ee by the 1,2-addition of a phytol-derived Grignard reagent to an α-bromo enone prepared from 2,3-dimethylquinone.