Synthesis of unsaturated hydroxy acids by the cobalt carbonyl and phase transfer catalyzed carbonylation of vinyl epoxides

Phase transfer catalyzed reaction of vinyl epoxides with carbon monoxide, methyl iodide, catalytic amounts of cobalt carbonyl and TDA-1, affords β-hydroxy acids. High regioselectivity was observed in some cases.     

Synthesis of heteroaromatic carboxylic acids by carbonylation of hetaryl halides with catalysts based on cobalt carbonyl modified with epoxides

A new method for the synthesis of heteroaromatic acids and their derivatives (esters and salts) by carbonylation of the corresponding halides was developed. Hetaryl halides were activated in alcoholic-alkali medium by highly active catalytic systems based on cobalt carbonyl modified with epoxides, developed previously for carbonylation of aryl halides.     

Mechanism of the catalytic carbonylation of aryl halides with a modified cobalt carbonyl

Investigation of the mechanism of the carbonylation of aryl halides in a catalytic system consisting of cobalt carbonyl, terminal olefin oxide, and base showed that this catalytic system activates aryl halides via a radical anion mechanism. The kinetic regularities of the process together with IR spectral data suggest reversible formation of the active catalytic complex under the reaction condition. The complex is a cyclic metal lactone, and it can form not only from olefin oxide but also from its methanolysis product, the corresponding glycol monomethyl ether.     

Cobalt carbonyl catalyzed sRN1 carbonylation of aryl and vinyl halides by phase transfer catalysis

The phase transfer catalyzed, cobalt carbonyi catalyzed carbonylation (1 atm. P.) of aryl and vinyi bromides under photostimulation (350 nm) affords the corresponding unsaturated acids in high yield.     

Polymerization of acetylenes catalyzed by rhenium carbonyl halides

The homogeneous catalyst Re(CO)₅X (X = Cl, Br) was found to promote the homopolymerization of terminal alkynes at elevated temperatures. Detection and structure characterization of low-molecular-weight products provided evidence of the formation of a metal–acetylide species as the initiator of polymerization, and propagation occurs by a series of insertion reactions of coordinated alkynes into metal–carbon bonds of the growing chain. Evidence of the active forms of the catalyst comes from studies on gas evolution, catalyst derivatization, and copolymerization reactions. The final polymers have a linear, polyconjugated macrostructure, and the formation of aromatic species was not detected in these reactions.     

Carbonylation of chlorobiphenyls catalyzed by modified cobalt carbonyl

Dichlorobiphenyls having both chlorine atoms in the same benzene ring undergo mild carbonylation in the presence of 1,2-epoxypropane-modified carbonyl cobalt complex to give biphenylcarboxylic acid esters. Monochlorobiphenyls fail to react under analogous conditions. The rate and selectivity of the reaction depend on the position of chlorine atoms. Carbonylation of dichlorobiphenyls having a chlorine atom in the meta position occurs preferentially at that position. 2,4-Dichlorobiphenyl gives rise mainly to the carbonylation product at the 2-position.     

Methane oxidative carbonylation catalyzed by rhodium chalcogen halides over carbon supports

Gas phase carbonylation of methane is studied in the presence of molecular oxygen over pure carbon carriers and carbon supported rhodium chalcogen halides. Activated carbons and fullerene blacks have been used as carbon supports. XPS and IR-spectroscopy data show the formation of rhodium chalcogen halides in solids prepared by different methods. We have found that the productivity of acetic acid by carbon supported rhodium chalcogen halides depends strongly on the carbon carrier and the method of the catalyst preparation. Namely, the catalyst with highest productivity for the acetic acid is prepared by synthesizing the rhodium chalcogen halide over the carbon support followed by thermal destruction. We have also found that rhodium chalcogen halides over activated carbons are more active compared with fullerene supported catalysts.     

The regiospecific cobalt carbonyl catalyzed synthesis of dienones and trienones by phase transfer catalysis

The phase transfer catalyzed, cobalt carbonyl catalyzed reaction of dienes, and a triene, with methyl iodide and carbon monoxide [r.t., 1 atm. P] is highly regiospecific, affording E-conjugated enones.     

Intermediates of the PTC carbonylation of benzyl halides by cobalt carbonyls, II

The structures of intermediates in the PTC carbonylation of two fluorinated benzyl halide substrates were studied. X-ray crystal and molecular structure of 2- and 3-fluorobenzylcobalt tricarbonyl triphenylphosphine derivatives was determined. The supposed influence of structural parameters on the reactivity is discussed.     

DFT computational study of the mechanism of allyl halides carbonylation catalyzed by nickel tetracarbonyl

A theoretical investigation at the DFT(B3LYP) level on the carbonylation reaction of allyl bromide catalyzed by nickel tetra-carbonyl Ni(CO)(4) is discussed. The computational results show the following: (i) Three main steps characterize the catalytic cycle: (a) an oxidative addition step, (b) a carbonylation step, and (c) a reductive elimination step where the acyl product is obtained and the catalyst is regenerated. (ii) Both Ni(CO)(3) and Ni(CO)(4) complexes can behave as "active" catalytic species. (iii) The oxidative addition leads to the formation of either eta(3) or eta(1)-allyl nickel complexes, which are involved in a fast equilibrium. (iv) The carbonylation occurs much more easily on the eta(1) than on the eta(3) intermediates.     

Rhodium(I) catalyzed carbonylation reactions of halides and ethers

Benzylic bromides and methyl iodide react with ethers, carbon monoxide, potassium iodide, and the dimer of chloro(1,5-hexadiene)rhodium($\text{I}$) to give esters in good yields.     

The mechanism of transition metal catalyzed carbonylation of allyl halides: A theoretical investigation

The mechanism of the carbonylation reaction of allyl halides catalyzed by nickel (Ni(CO)₄) and palladium (Cl₂Pd(PPh₃)₂) complexes is theoretically investigated at the DFT level using the hybrid B3LYP functional. The favored reaction path to carbonylation corresponds, for both catalysts, to a direct attack of the halogen on the metal. This affords η¹ intermediates that can undergo the final carbonylation step. It is also possible to obtain the acyl product (β,γ-unsaturated acyl halides) from η² and/or η³ intermediates. However, in this case, the barrier of the rate-determining step to carbonylation is much higher. Since a channel on the potential surface connects rather easily the η² or η³ intermediates to the η¹ intermediates, an alternative and competitive path leading to the acyl products can originate from the η² or η³ intermediates, follow the η²/η³ → η¹ transformation, then undergo the final carbonylation step.     

A green procedure for the protection of carbonyl compounds catalyzed by iodine in ionic liquid

Aldehydes and ketones are protected with ethylene glycol in the presence of a catalytic amount of iodine in PEG ionic liquid (IL 400) under mild conditions to afford the corresponding ketals in good yields. The recovery of iodine is facilitated by the ionic liquid. The recovered catalyst was reused six times with consistent activity.     

钴纳米粒子催化水相费托合成

水相费托合成可以在远低于传统温度下实现,其低温高效的特点使其具有重要的应用潜力. 本文制备了水相稳定且可循环利用的Co纳米粒子并应用于水相费托反应,150℃下活性为7.4×10^-7mol_CO g_Co^-1 s^-1,C₅₊选择性接近40%,是目前纯钴水相费托合成的最好结果,而其它方法合成的催化剂在150℃时活性低下. 对催化剂进行了粒径、结构、成分测定和原位红外光谱检测,研究了催化剂在反应中的重构过程和B掺杂效应.     

C-H arylation of unactivated arenes with aryl halides catalyzed by cobalt porphyrin

A general procedure for cobalt-catalyzed direct C-H arylation of unactivated arenes has been discovered. This method employs aryl halides as the direct coupling partners with arenes without using any Grignard-type reagents. This catalysis opens a new methodology for the preparation of symmetrical as well as unsymmetrical biaryls in a user-friendly approach.     

Palladium complex-catalyzed carbonylation of organic halides in the presence of cyclic ethers: Halohydrin ester synthesis

Cyclic ethers were cleaved by palladium complex-catalyzed carbonylation of organic halides to give halohydrin esters.     

Palladium‐catalyzed carbonylation of quaternary ammonium halides to tertiary amides

Catalytic carbonylation of quaternary ammonium salts under anhydrous conditions was investigated using palladium catalyst. The carbonylation of tetramethylammonium iodide was chosen as a model reaction and studied systematically. Ligand‐free PdCl₂ showed efficient catalytic performance for this transformation. A palladium catalyst loading as low as 0.05 mol% was sufficient for high yield (96.9%) of N,N‐dimethylacetamide, corresponding to a turnover frequency of 242 h^?1. Under optimum conditions, several other quaternary ammonium halides were also carbonylated to corresponding tertiary amides in moderate to excellent yields. The catalytic activity of commercial palladium on activated carbon (Pd/C) catalyst was also evaluated. The Pd/C catalyst exhibited high activity for this carbonylation reaction and could be recycled six times with a slight decrease in activity. Furthermore, mechanistic considerations concerning Pd‐catalyzed carbonylation of quaternary ammonium halides were also discussed. Copyright © 2014 John Wiley & Sons, Ltd.     

The use of phase-transfer catalysis in palladium-catalyzed carbonylation of organic halides

Aryl, benzyl, vinly and heterocyclic halides RX have been converted in high yields into the corresponding acids RCOOH by adding the RX with a little PPh₃ slowly to a rapidly stirred mixture of aqueous NaOH, [Pd(PPh₃)₂Cl₂], and n-Bu₄NI in toluene under a CO atmosphere.     

The mechanism of the stoichiometric phase transfer carbonylation of benzyl bromide by the cobalt carbonyl anion

The kinetics of the stoichiometric phase-transfer carbonylation of benzyl bromide by the cobalt carbonyl anion have been investigated. Pseudo first order constants vary linearly with the amount of tetrabutylammonium chloride present. The effect of the solvent is partly due to its ability to extract the ion pair Bu₄N⁺Co(CO)₄^? into the organic phase. This ion pair is barely soluble in water and the amount of Co(CO)₄^? anion in the organic phase is kept constant by a simple anion exchange mechanism without migration of the tetrabutylammonium cation.     

One-pot amide synthesis from allyl or benzyl halides and amines by Pd-catalysed carbonylation

Amides can be prepared from allyl or benzyl halides and primary or secondary amines, using Pd(0) catalyst under CO pressure, in a one-pot synthesis. The reaction proceeds through the acyl palladium halide formation which undergoes an acylic nucleophilic substitution from the amine.