Palladium-Catalyzed Difunctionalization of 1,3-Diene with Amine and Disilane under a Mild Re-oxidation System.

A highly regioselective and stereoselective difunctionalization reaction of 1,3-diene with amine and disilane to form C-N and C-Si bonds via a one-step Pd/Cu/O2 system is disclosed. The difunctionalization reaction affords allylic silanes, including the allylic amine moiety, in up to 92 % yield in the absence of any acid, base, or external ligand. The developed synthetic methodology can be scaled to 100 g in high yield with high Z-selectivity, which demonstrates the feasibility of the reaction for industrial applications.

Cross ß-alkylation of primary alcohols catalysed by DMF-stabilized iridium nanoparticles.

A simple method for the cross ß-alkylation of linear alcohols with benzyl alcohols in the presence of DMF-stabilized iridium nanoparticles was developed. The nanoparticles were prepared in one-step and thoroughly characterized. Furthermore, the optimum reaction conditions have a wide substrate scope and excellent product selectivity.

N,N-Dimethylformamide-stabilised palladium nanoparticles combined with bathophenanthroline as catalyst for transfer vinylation of alcohols from vinyl ether.

We report N,N-dimethylformamide-stabilised Pd nanoparticle (Pd NP)-catalysed transfer vinylation of alcohols from vinyl ether. Pd NPs combined with bathophenanthroline exhibited high catalytic activity. This reaction proceeded with low catalyst loading and the catalyst remained effective even after many rounds of recycling. The observation of the catalyst using transmission electron microscopy and dynamic light scattering implied no deleterious aggregation of Pd NPs.

Iridium Complex-Catalyzed C2-Extension of Primary Alcohols with Ethanol via a Hydrogen Autotransfer Reaction.

The development of a C2-extension of primary alcohols with ethanol as the C2 source and catalysis by [Cp*IrCl2]2 (where Cp* = pentamethylcyclopentadiene) is described. This new extension system was used for a range of benzylic alcohol substrates and for aliphatic alcohols with ethanol as an alkyl reagent to generate the corresponding C2-extended linear alcohols. Mechanistic studies of the reaction by means of intermediates and deuterium labeling experiments suggest the reaction is based on hydrogen autotransfer.

Palladium-Catalyzed Oxidative Silylation of Simple Olefins To Give Allylsilanes Using Hexamethyldisilane and Molecular Oxygen as the Sole Oxidant.

A Pd-catalyzed oxidative silylation of simple olefins with hexamethyldisilane to give allylsilanes has been achieved using molecular oxygen as the sole oxidant. The reaction provides a useful protocol to access synthetically useful allylsilanes from easily accessible simple olefins and hexamethyldisilane without using any oxidants other than O2.

Low-valent niobium-catalyzed intermolecular [2 + 2 + 2] cycloaddition of tert-butylacetylene and arylnitriles to form 2,3,6-trisubstituted pyridine derivatives.

A catalytic system based on low-valent niobium has been developed, consisting of NbCl5, Zn, and an alkoxysilane. This combination has been shown to be an efficient catalyst for the synthesis of pyridine derivatives from the intermolecular cycloaddition of alkynes and nitriles via a niobacyclopentadiene intermediate.

Palladium-catalyzed Z-selective oxidative amination of ortho-substituted primary anilines with olefins under an open air atmosphere.

The Pd-catalyzed oxidative amination of olefins with primary anilines has been achieved using molecular dioxygen as the sole oxidant. The use of ortho-substituted primary anilines such as ortho-toluidine was the key to the successful development of this reaction, providing the corresponding N-alkenyl substituted anilines in high yields with unusually high levels of Z-selectivity.

Iridium-catalyzed alkylation of methylquinolines with alcohols.

Iridium-catalyzed alkylation of methylquinolines at the methyl substituent was achieved using alcohols as alkylating agents. The reaction proceeded through a transfer hydrogenation pathway from the alcohol to the Ir complex, affording an aldehyde and Ir-H species, followed by base-assisted aldol condensation and hydrogenation. This method provides an atom-economical and convenient route to alkylquinolines from easily accessible methylquinolines.

N,N-Dimethylformamide-stabilized ruthenium nanoparticle catalyst for ß-alkylated dimer alcohol formation via Guerbet reaction of primary alcohols.

N,N-Dimethylformamide-stabilized Ru nanoparticles (NPs) provide a highly efficient catalyst for the Guerbet reaction of primary alcohols. DMF-modified Ru NPs were synthesized, and characterized by transition electron microscopy, and X-ray absorption spectroscopy, X-ray photoelectronspectroscopy, and Fourier-transform infrared spectroscopy. The Ru NP catalyst was highly durable during catalytic reactions under external additive/solvent-free conditions.

Dimethylacetamide-stabilized ruthenium nanoparticles for catalysing α-alkylations of amides with alcohols.

α-Alkylation reactions between amides and alcohols, with dimethylacetamide-stabilized Ru nanoparticles (NPs) as the catalyst, were investigated. The reactions proceeded with low catalyst loadings compared to metal complexes. Characterizations of the Ru NPs were performed by X-ray photoelectron spectroscopy, X-ray absorption fine structure spectroscopy, and various techniques. Control experiments revealed the reaction mechanisms, which proceeded via hydrogen autotransfer with alcohols.

Active low-valent niobium catalysts from NbCl5 and hydrosilanes for selective intermolecular cycloadditions.

An active niobium catalyst was developed via a simple and nontoxic reduction method from NbCl(5)/hydrosilane and utilized for the selective [2 + 2 + 2] cycloaddition reaction of terminal alkynes and alkenes/α,ω-dienes, to give 1,3-cyclohexadiene derivatives in high yields with excellent chemo- and regioselectivity.

Iridium-catalyzed oxidative methyl esterification of primary alcohols and diols with methanol.

Oxidative methyl esterification of primary alcohols and diols with methanol was successfully achieved, using acetone as a hydrogen acceptor, under the influence of an iridium complex combined with 2-(methylamino)ethanol (MAE) as catalyst.

Palladium-Catalyzed Three-Component Silylalkoxylation of 1,3-Diene with Alcohol and Disilane via Oxidative Coupling.

A regioselective and Z-selective three-component silylalkoxylation of 1,3-diene using various alcohols, disilane, and a catalytic Pd/Cu/1,4-benzoquinone/O2 system is established in this Letter. The reaction generates tetra-substituted allyl silanes containing allyl ether moieties in up to 80% isolated yield and on a 1-10 mmol scale via oxidative coupling. A wide variety of substrates, including benzyl alcohol derivates, aliphatic alcohols, and bioactive compounds such as cholesterol, are suitable for use in the developed reaction system.

Cross ß-arylmethylation of alcohols catalysed by recyclable Ti-Pd alloys not requiring pre-activation.

Ti-Pd alloy catalysts were developed for the cross ß-arylmethylation between arylmethylalcohols and different primary alcohols via a hydrogen autotransfer mechanism. The alloy catalysts could be reused multiple times without the need for pre-activation. Analysis of the reaction solution by inductively coupled plasma atomic absorption spectroscopy indicated that only a minimal amount of Ti and no Pd was leached from the catalyst.

Catalytic enantioselective intramolecular Tishchenko reaction of meso-dialdehyde: synthesis of (S)-cedarmycins.

The first successful example of a catalytic enantioselective intramolecular Tishchenko reaction of a meso-dialdehyde in the presence of a chiral iridium complex is described. Chiral lactones were obtained in good yields with up to 91% ee. The obtained enantioenriched lactones were utilized for the first synthesis of (S)-cedarmycins A and B.

Iridium-catalyzed alpha-alkylation of acetates with primary alcohols and diols.

Acetates were successfully alkylated with primary alcohols and alpha,omega-diols in the presence of tert-BuOK under the influence of [IrCl(cod)](2). For instance, the reaction of tert-butyl acetate with n-butanol in the presence of tert-BuOK as a base and [IrCl(cod)](2) as a catalyst in tert-BuOH at 100 degrees C produced tert-butyl hexanoate in good yield. When the alpha,omega-diol 1,9-nonanediol was employed, di-tert-butyl tridecanoate was obtained. These reactions are the first report of the alkylation of acetates using alcohols as alkylating agents. This method provides a very convenient direct route to carboxylates, which are very important raw materials in organic and industrial chemistry.

Iridium-catalyzed coupling reaction of primary alcohols with 2-alkynes leading to hydroacylation products.

A novel iridium-catalyzed intermolecular coupling reaction of primary alcohols or aldehydes with 2-alkynes was successfully achieved with high regioselectivity to give hydroacylation products such as alpha,beta-unsaturated ketones in good yields. The mechanistic investigation of the reaction strongly indicated that the coupling proceeds through the initial formation of homoallylic alcohols followed by dehydrogenation to beta,gamma-unsaturated ketones and then isomerisation, which leads to the hydroacylation products.

NbCl3-catalyzed intermolecular [2+2+2] cycloaddition of alkynes and alpha,omega-dienes: highly chemo- and regioselective formation of 5-omega-alkenyl-1,4-substituted-1,3-cyclohexadiene derivatives.

Intermolecular [2+2+2] cycloaddition of tert-butylacetylene with alpha,omega-dienes was successfully achieved by NbCl(3)(DME) catalyst to afford 5-omega-alkenyl-1,4-disubstituted-1,3-cyclohexadienes in excellent yields with high chemo- and regioselectivity.

Synthesis of omega-hydroxy carboxylic acids and alpha,omega-dimethyl ketones using alpha,omega-diols as alkylating agents.

Synthesis of omega-hydroxy carboxylic acids and alpha,omega-dimethyl diketones was successfully achieved by using alpha,omega-diols as alkylating agents under the influence of an iridium catalyst. For example, the alkylation of butyl cyanoacetate with 1,13-tridecanediol in the presence of [IrCl(cod)](2) or [IrCl(coe)(2)](2) gave rise to butyl 2-cyano-15-hydroxypentadecanoate in good yield which is easily converted to cyclopentadecanolide (CPDL). In addition, the alkylation of acetone with 1,10-decanediol in the presence of [IrCl(cod)](2) and KOH resulted in an important muscone precursor, 2,15-hexadecanedione (HDDO), in good yield.

Direct oxidative coupling of benzenes with acrylonitriles to cinnamonitriles catalyzed by Pd(OAc)(2)/HPMoV/O(2) system.

A facile direct synthesis of cinnamonitriles from acrylonitriles and benzenes is successfully achieved by using Pd(OAc)(2)/HPMoV/O(2) catalyst system via the direct C-H bond activation of benzenes using molecular oxygen as a terminal oxidant.