21895-83-0

Upstream product

• 286-20-4 cyclohexane-1,2-epoxide 
• 106-95-6 allyl bromide 
• 79643-88-2 1-(2-propen-1-yloxy)cyclohexene 
• 24796-87-0 2-bromo-cyclohexanol 
• 107-05-1 3-chloroprop-1-ene 
• 24850-33-7 allyltributylstanane 
• 2425-33-4 2-bromocyclocyclohexanol 
• 94-66-6 2-allylcyclohexan-1-one 
• 94-66-6 (R)-2-allylcyclohexanone 
• 1745-81-9 o-Allylphenol 

Downstream Products

• 94-66-6 2-allylcyclohexan-1-one 
• 21895-84-1 1-Brom-2-<β-brompropyl>-cyclohexan 
• 115022-81-6 C₁₆H₂₂Cl₂O₂Te 
• 115022-86-1 2-(4-Methoxy-phenyltellanylmethyl)-octahydro-benzofuran 

Relevant academic research and scientific papers

Direct Asymmetric Hydrogenation and Dynamic Kinetic Resolution of Aryl Ketones Catalyzed by an Iridium-NHC Exhibiting High Enantio- and Diastereoselectivity

A chiral iridium carbene-oxazoline catalyst is reported that is able to directly and efficiently hydrogenate a wide variety of ketones in excellent yields and good enantioselectivity (up to 93 % ee). Moreover, when using racemic α-substituted ketones, excellent diastereoselectivities were obtained (dr 99:1) by dynamic kinetic resolution of the in situ formed enolate. Overall, the herein described hydrogenation occurs under ambient conditions using low hydrogen pressures, providing a direct and atom efficient method towards chiral secondary alcohols.

Chiral Imidazo[1,5- a]pyridine-Oxazolines: A Versatile Family of NHC Ligands for the Highly Enantioselective Hydrosilylation of Ketones

Herein we report the synthesis and application of a versatile class of N-heterocyclic carbene ligands based on an imidazo[1,5-a]pyridine-3-ylidine backbone that is fused to a chiral oxazoline auxiliary. The key step in the synthesis of these ligands involves the installation of the oxazoline functionality via a microwave-assisted condensation of a cyano-azolium salt with a wide variety of 2-amino alcohols. The resulting chiral bidentate NHC-oxazoline ligands form stable complexes with rhodium(I) that are efficient catalysts for the enantioselective hydrosilylation of structurally diverse ketones. The corresponding secondary alcohols are isolated in good yields (typically >90%) with good to excellent enantioselectivities (80-93% ee). The reported hydrosilylation occurs at ambient temperatures (40 °C), with excellent functional group tolerability. Even ketones bearing heterocyclic substituents (e.g., pyridine or thiophene) or complex organic architectures are hydrosilylated efficiently, which is discussed further in this report.

Catalytic hydrogenation of aromatic rings catalyzed by Pd/NiO

A simple and efficient heterogeneous palladium catalyst was prepared for aromatic ring hydrogenation. The catalyst was prepared by a reduction-deposition method and exhibited high activity and selectivity for the hydrogenation of a variety of substituted aromatic compounds to the corresponding cyclohexane and cyclohexanol derivatives with up to 99% yields. The catalyst was characterized by BET, TEM, XRD, XPS and ICP. Meanwhile the reusability of the catalyst was investigated, and it can be reused for several runs without significant deactivation.

Alkene isomerisation catalysed by a ruthenium PNN pincer complex

The [Ru(CO)H(PNN)] pincer complex based on a dearomatised PNN ligand (PNN: 2-di-tert-butylphosphinomethyl-6-diethylaminomethylpyridine) was examined for its ability to isomerise alkenes. The isomerisation reaction proceeded under mild conditions after activation of the complex with alcohols. Variable-temperature (VT) NMR experiments to investigate the role of the alcohol in the mechanism lend credence to the hypothesis that the first step involves the formation of a rearomatised alkoxide complex. In this complex, the hemilabile diethylamino side-arm can dissociate, allowing alkene binding cis to the hydride, enabling insertion of the alkene into the metal-hydride bond, whereas in the parent complex only trans binding is possible. During this study, a new uncommon Ru0 coordination complex was also characterised. The scope of the alkene isomerisation reaction was examined. The catalyst tested positive! A dearomatised ruthenium PNN (2-di-tert-butylphosphinomethyl-6-diethylaminomethylpyridine) pincer complex, [Ru(CO)H(PNN)], was evaluated as an alkene isomerisation catalyst. The isomerisation reaction was greatly accelerated by the addition of alcohols, in particular isopropanol. Isomerisation of terminal to internal alkenes took place at room temperature. A mechanism was proposed based on variable-temperature NMR spectroscopy.

Use of pyridine-coated star-shaped ROMP polymer as the supporting ligand for ruthenium-catalyzed chemoselective hydrogen transfer reduction of ketones

"Soluble" star-shaped polymers containing a pyridine ligand at the chain ends, prepared by adopting sequential living ring-opening metathesis polymerizations (ROMP) of norbornene and a cross-linking reagent using Mo(CHCMe2Ph)(N-2,6-iPr2C6H 3)(OtBu)2 via a "core-first" approach, have been employed as ligands for Ru-catalyzed chemoselective hydrogen transfer reductions of various ketones (cyclohexanone, 5-hexen-2-one, 2-allylhexanone, 5-isopropenyl-2-methylcyclohexanone). The activity increased upon addition of the above polymer as the ligand: the prepared catalyst could be recovered quantitatively and reused without decreasing in both activity and selectivity.

Palladium-catalyzed decarboxylative asymmetric allylic alkylation of enol carbonates

Palladium-catalyzed decarboxylative asymmetric allylic alkylation (DAAA) of allyl enol carbonates as a highly chemo-, regio-, and enantioselective process for the synthesis of ketones bearing either a quaternary or a tertiary R-stereogenic center has been investigated in detail. Chiral ligand L4 was found to be optimal in the DAAA of a broad scope of cyclic and acyclic ketones including simple aliphatic ketones with more than one enolizable proton. The allyl moiety of the carbonates has been extended to a variety of cyclic or acyclic disubstituted allyl groups. Our mechanistic studies reveal that, similar to the direct allylation of lithium enolates, the DAAA reaction proceeds through an "outer sphere" S N2 type of attack on the π-allylpalladium complex by the enolate. An important difference between the DAAA reaction and the direct allylation of lithium enolates is that in the DAAA reaction, the nucleophile and the electrophile were generated simultaneously. Since the π-allylpalladium cation must serve as the counterion for the enolate, the enolate probably exists as a tight-ion-pair. This largely prevents the common side reactions of enolates associated with the equilibrium between different enolates. The much milder reaction conditions as well as the much broader substrate scope also represent the advantages of the DAAA reaction over the direct allylation of preformed metal enolates.

A novel 1,3-stannyl shift promoted intramolecular cyclizations of α-stannyl radicals with a formyl group

(equation presented) Reactions of α-stannyl bromides and xanthates with tributyltin hydride generate α-stannyl radicals. Intramolecular cyclizations of these radicals with a formyl group afford γ-stannyl alkoxy radicals that undergo a 1,3-stannyl shift fr

Direct Free-Radical Substitutions on Allyl and Vinyl Halides Using Alkyl Halides/Hexabutylditin

Allyl and vinyl halides are excellent acceptors for tin-mediated substitutions by alkyl radicals generated from alkyl halides.

PHOTOINDUCED SINGLE ELECTRON TRANSFER (SET) INITIATED OXIDATIVE CLEAVAGE OF BENZYLIC ETHERS PROTECTING GROUP: A MILD AND EFFICIENT PROCEDURE

A very efficient and mild method for benzylic ether deprotection in neutral medium by photoinduced single electron transfer initiated oxidative cleavage is reported.

ONE ELECTRON C-C BOND FORMING REACTIONS VIA ALLYLSTANNANES: SCOPE AND LIMITATIONS

Free radical (or "one-electron") methodology for carbon-carbon bond forming reactions using allylstannanes is described in detail.Such reactions have the advantages of tolerating quite complex functionality in the substrate and of being nearly stoichiometric in reagents, and not requiring extensive experimentation for application to new substrates.