Atm Of Carbon Monoxide Research Articles

Palladium-catalyzed synthesis of quinoxaline derivatives

A palladium-catalyzed reductive N-heteroannulation of enamines derived from 2-nitrobenzenamines forming mixtures of 1,2-dihydroquinoxalines and 3,4-dihydroquinoxalin-2-ones is described. The reactions are performed using bis(dibenzylideneacetone)palladium(0), 1,3-bis(diphenylphosphino)propane, and 1,10-phenanthroline in DMF under 6 atm of carbon monoxide at 70 °C.

Carbonylative Ring Opening of Terminal Epoxides at Atmospheric Pressure

The carbonylative opening of terminal epoxides under mild conditions has been developed using Co2(CO)8 as the catalyst. Under 1 atm of carbon monoxide and at room temperature in methanol, propylene oxide is converted to methyl 3-hydroxybutanoate in up to 89% yield. This transformation is general for many terminal epoxides bearing alkyl, alkenyl, aryl, alkoxy, chloromethyl, phthalimido, and acetal functional groups. The opening takes place without epimerization at the secondary stereocenter.

Sum Frequency Generation Imaging Microscopy of CO on Platinum

Sum frequency vibrational spectroscopy is utilized as an imaging technique to distinguish and compare the local response of carbon monoxide (CO) covered platinum (Pt) polycrystalline surface versus the average response of the investigated area. The Pt electrode was prepared using the standard method and was exposed to approximately 1 atm of CO(g). SFG images and vibrational spectra were obtained where the contrast is based on the intrinsic nature of each peak in the CO vibrational spectrum. The illustration of the images and the chemical maps of CO on the platinum surface showed the distribution of the CO across the observed area. The results obtained by comparing the local and the average response confirmed the spatial distributions of the CO on the platinum sample which are due to several reasons such as dipole-dipole coupling and surface coverage. This finding has a significant contribution toward recognizing that surfaces usually considered homogeneous may in fact be quite heterogeneous.

Carbonylative Cross‐Coupling Reaction of Ethynylstibane with Aryl Iodides.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.

Carbonylative Cross-Coupling Reaction of Ethynylstibane with Aryl Iodides

Palladium-catalyzed carbonylative cross-coupling reaction of ethynylstibane (PhSbPh(2)) and aryl iodides (Ar-I) is described. The reaction of the stibanes and the halides under 1 atm of carbon monoxide in N,N-dimethylacetamide using a combination of 5 mol% Pd(OAc)(2) and 4 equivalents (20 mol%) of PPh(3) brought about carbonylative cross-coupling reaction to afford arylethynylketones [ArC(O)Ph] in good yields along with a small amount of directly coupled products, aryl acetylens (ArPh). Formation of the side product was completely suppressed by conducting the reaction under high CO pressure (20 atm) conditions. The present method provides a variety of carbonylated products in good yield even with electron-deficient aryl iodides which usually give inferior results due to their tendency to undergo decarbonylation in the cross-coupling reaction of ethynylstibanes and acyl halides.

Synthesis of Coumarins Catalyzed by Heterobimetallic Co/Rh Nanoparticles.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Synthesis of Coumarins Catalyzed by Heterobimetallic Co/Rh Nanoparticles

Described here is the use of cobalt/rhodium (Co2Rh2) heterobimetallic nanoparticles in the catalytic synthesis of coumarins via cyclocarbonylation of alkynes with 2-iodophenol under 1 atm of carbon monoxide and reaction of phenol with propiolic ­esters.

Immobilized cobalt/rhodium heterobimetallic nanoparticle-catalyzed silylcarbocylization and carbonylative silylcarbocyclization of 1,6-enynes.

Reaction of 1,6-enynes with a hydrosilane in the presence of immobilized cobalt/rhodium bimetallic nanoparticles gives 2-methyl-1-silylmethylidene-2-cyclopentanes in the absence of carbon monoxide and 2-formylmethyl-1-silylmethylidene-2-cyclopentanes under 1 atm of carbon monoxide, respectively. [reaction: see text]

Preparations of sulfido-tricobalt clusters containing pyridyl type ligands: insertion of carbon monoxide into cobaltcarbon bond

Abstract The reaction of 2-mercaptopyridine with 1.5 M equivalent of Co 2 (CO) 8 in THF at 25 °C for 1 h gave a sulfido-tricobalt cluster (μ 3 -S)Co 3 (CO) 7 (μ-C,NC 5 H 4 N) ( 1 ). Further reaction of 1 with diphenyl-2-pyridylphosphine (PPh 2 py) under mild reaction condition afforded a PPh 2 py bridged complex (μ 3 -S)Co 3 (CO) 5 [(μ-C(O),NC 5 H 4 N(CO))(μ-P,NPPh 2 py)] ( 3 ). The X-ray structure analysis of 3 revealed that a carbonylation process occurred at the CoC(pyridyl) bond of 1 . Carbonylation of 1 at the same position also took place under 1 atm of carbon monoxide at room temperature and formed (μ 3 -S)Co 3 (CO) 7 [(μ-C(O),NC 5 H 4 N(CO))] ( 4 ). Similar results were obtained in the reaction of 2-quinolinethiol with 1.5 M equivalent of Co 2 (CO) 8 . A sulfido-tricobalt cluster (μ 3 -S)Co 3 (CO) 7 (μ-C,NC 9 H 6 N) ( 5 ) and tris-quinolinethiolate chelated cobalt complex [Co(μ-S,NSC 9 H 6 N) 3 ] ( 6 ) were obtained. In contrast to 1 , carbonylation did not occur in 5 at 1 atm of carbon monoxide even at 60 °C for prolonged reaction hours. However, treatment of 5 with PPh 2 py yielded a PPh 2 py coordinated (μ 3 -S)Co 3 (CO) 6 [(μ-C,NC 9 H 6 N)(PPh 2 py)] ( 7 ) as the major product, which is accompanied with a small amount of PPh 2 py bridged (μ 3 -S)Co 3 (CO) 5 [(μ-C(O),NC 9 H 6 N(CO))(μ-P,NPPh 2 py)] ( 8 ). Carbonylation did occur at the CoC(quinolinyl) bond of 5 , even though less efficient than that of 1 , while reacted with a PPh 2 py ligand. The same reaction pattern was observed for the reaction of 2-mercapto-nicotinic acid methyl ester with 1.5 M equivalent of Co 2 (CO) 8 ; a sulfido-tricobalt cluster (μ 3 -S)Co 3 (CO) 7 (μ-C,NC 5 H 3 NC(O)OCH 3 ) ( 9 ) was obtained as the major product. The crystal structures of all eight new complexes have been determined.

Synthesis of coumarins via palladium-catalyzed carbonylative annulation of internal alkynes by o-iodophenols

A variety of substituted coumarins have been prepared in good yields by the palladium-catalyzed coupling of o-iodophenols with internal alkynes and 1 atm of carbon monoxide. Unlike most of the previous work on the palladium-catalyzed carbonylation of alkynes, the insertion of the internal alkyne occurs in preference to the insertion of CO.

Copper-catalyzed cross-coupling of α-seleno-acylzirconocene chloride with haloalkynes: Synthesis of α-seleno-substituted vinyl alkynyl ketones

The copper-catalyzed cross-coupling reaction of α-selenoacylzirconocene chloride 3 with haloalkynes in the presence of carbon monoxide gives α-seleno-substituted vinyl alkynyl ketones 5 in moderate yields. The reaction conditions are neutral and mild enough (room temperature, 1 atm carbon monoxide) that other functional groups in either coupling partner can be brought unaltered into the coupled product. The E geometry in the α-alkylseleno vinylzirconocene reagent is maintained during the coupling reaction. © 2000 John Wiley & Sons, Inc. Heteroatom Chem 11:91–93, 2000

Copper‐catalyzed cross‐coupling of α ‐seleno‐acylzirconocene chloride with haloalkynes: Synthesis of α ‐seleno‐substituted vinyl alkynyl ketones

The copper-catalyzed cross-coupling reaction of α-selenoacylzirconocene chloride 3 with haloalkynes in the presence of carbon monoxide gives α-seleno-substituted vinyl alkynyl ketones 5 in moderate yields. The reaction conditions are neutral and mild enough (room temperature, 1 atm carbon monoxide) that other functional groups in either coupling partner can be brought unaltered into the coupled product. The E geometry in the α-alkylseleno vinylzirconocene reagent is maintained during the coupling reaction. © 2000 John Wiley & Sons, Inc. Heteroatom Chem 11:91–93, 2000

Synthesis of Carboxylic Acids through the Formation of C–C Bond between Saturated Hydrocarbons and CO in the Presence of Mg/K2S2O8/TFA System

Abstract Magnesium powder (Mg) promoted the carboxylation reaction of saturated hydrocarbons with carbon monoxide (CO) in the presence of potassium peroxodisulfate (K2S2O8) in trifluoroacetic acid (TFA) to yield the corresponding carboxylic acids and alkyl trifluoroacetates. About 80% conversion of cyclohexane was achieved when 5 mmol of magnesium, 5 mmol of potassium peroxodisulfate, 3 mL of TFA, 1 mmol of cyclohexane, 50 atm of CO were used at 80 °C for 30 h.

Copper(I) chloride-ethanediamine complex supported on silica gel as adsorbent for carbon monoxide

A copper(I) chloride- N,N,N′,N′-tetramethyl-1,2-ethanediamine complex supported on silica gel was prepared by mixing porous silica gel with an acetonitrile solution containing the complex composed of copper(I) chloride (CuCl) and N,N,N′,N′-tetramethyl-1,2-ethanediamine (M4en) under nitrogen, followed by removal of liquid phase under reduced pressure. The resulting silica gel, 6.0 g, supported 4.92 mmol of 1 : 1 CuCl-M4en complex. It rapidly adsorbed carbon monoxide (CO) at 30°C under 1.0 atm of CO, and the equilibrium amount of adsorbed CO was 4.30 mmol (87 mol% against supported complex). The adsorbed CO was rapidly desorbed by maintaining it at 120°C under 1.0 atm or at 30°C under 0.1 mmHg. The adsorption-desorption cycle was repeated without any deterioration. The equilibrium amount of adsorbed CO (4.30 mmol) was 11.8 times that of adsorbed carbon dioxide (0.37 mmol), and 40.9 times that of adsorbed methane (0.11 mmol) at 30°C under 1.0 atm. The reversible and selective adsorption of CO was attributed to formation of 1: 1: 1 CuCl-M4en-CO complex. When the adsorbent contacted with oxygen, the CO-adsorbing ability decreased. The adsorbing ability was completely recovered by maintaining the adsorbent at 120°C under 1.0 atm of CO for 3 h.

C-N Bond Formation Reactions via Transition Metal Catalysis

Aminocarbonylation of N-2-propenyl-1, N-3-butenyl-4, and N-4-pentenylureas 8 proceeds smoothly under the Wacker-type conditions (cat. PdCl2, stoichiometric CuCl2, 1 atm of carbon monoxide at 0 °C - r.t.) and furnishes 2-imidazolidinone 4-acetic acids 2, tetrahydro-2-pyrimidinone 4-acetic acids 5 and bicyclic dihydrouracils 10, respectively, in good yields. Bicyclic pyrrolidine lactones 15 and piperidine lactones 18 are obtained under the similar conditions, endo-Carbamates 21 display completely different reactivity from exo-carbamates (e.g., 8', R=CO2Me), through which the chemoselective cyclization of 23 (e.g., R=CO2Me) either at the endo-carbamate moiety (providing 24, R=CO2Me) or at the exo-carbamate moiety (providing 25, R=CO2Me) is achieved only by changing the reaction medium (the former in trimethyl orthoacetate and the latter in methanol). 4-(1-Methoxycarbonylvinyl)-1,3-oxazolidin-2-ones 27 and -tetrahydro-1,3-oxazin-2-ones 29 are obtained in good yields under the similar conditions optimized for endo-carbamates 21. The nitrogen atom of 0-propargyl carbamates 31 add intramolecularly to the triple bond to furnish 4-alkylidene-1,3-oxazolidin-2-ones 32 by the catalysis of CuCl•Et3N. Similarly, CuCl•Et3N promotes the aminocyclization of biscarbamate 33 to provide 32 (R2=CH2OCONHTs), while Pd2(dba)3•CHCl3 selectively promotes the cyclization to furnish 34, the C2-C3 double bond of which undergoes a [2+2] cycloaddition with phenylacetylene and methyl acrylate. The enamine double bond reacts with methyl vinyl ketone and acrolein to provide [2+4] addition products. Allene carbamates 38 and 40 undergo cyclization to provide 4-vinyl-1,3-oxazolidin-2-ones 39 and 4-vinyltetrahydro-1,3-oxazin-2-ones 41, respectively, by the catalysis of Ag+•Et3N. The structurally related 43 (R=aryl, sulfonyl) are also obtained with high stereoselectivity by the reaction of cyclic carbamates 42 and isocyanates under the catalysis of Pd(PPh3)4. Allylic aminoalcohols derived from carbamates 39, 41, and 43 are utilized as probes to elucidate the electronic effects of the allylic amino and allylic hydroxyl groups on the stereoselective and/or regioselective cyclization reactions: Cope rearrangement (eq 21), endo-trig cyclization (eq 22), and iodoetherification (eq 23). Making contrast to the Ag+•Et3N catalyzed protioaminocyclization of 38 (eq 16), by the catalysis of Pd(PPh3)4, 0-2,3-butadienyl carbamates 55' undergo (2,3-butadien-2-yl)aminocyclization to provide 58. PdCl2, in the presence of an allylating agent (a large excess), promotes the allylaminocyclization of 55 and furnishes trans-56 in good yields and with excellent stereoselectivity.

Photolytic Reaction of Hydroxy Fischer Carbene Complexes: Synthesis of α-Hydroxy Esters

Photolytic reaction of in situ generated pentacarbonyl(1-hydroxyalkylidene)chromium complexes in the presence of an alcohol, under 6 atm of carbon monoxide, affords α-hydroxy-substituted esters in low to moderate yield. Acetals, formed via thermal decomposition of the carbenes, are in some cases the major product.

Photo-, electro-, and thermal carbonylation of alkyl iodides in the presence of group 7 and 8–10 metal carbonyl catalysts

Various transition-metal complexes including Group 7 and 8–10 metal carbonyls are highly active catalyst precursors for the photochemical carbonylation of alkyl iodides having β-hydrogens on saturated sp 3-carbons at room temperature under 1 atm of carbon monoxide. Primary, secondary and tertiary alkyl iodides are smoothly carbonylated by this catalyst system without β-hydride elimination (dehydrohalogenation) to give the corresponding esters or amides in high yields. In employment of Mn 2(CO) 10 as a catalyst, electrochemical carbonylation of alkyl iodides also occurred via generation of an anionic manganese carbonyl intermediate. Actually, anionic manganese carbonyl complexes (pentacarbonylmanganates) showed high catalytic activity for thermal carbonylation of alkyl iodides at room temperature under 1 atm of carbon monoxide without photo-irradiation and electrolysis. Mechanistic studies were performed with kinetics and ESR and it was suggested that the present photo-, electro- and thermal carbonylation would involve a non-chain radical mechanism.

Co2(CO)8-Catalyzed Ring-Opening Carbonylation of Cyclic Ethers Using N-Silylamines

Abstract Co2(CO)8-catalyzed ring-opening carbonylation of oxiranes and oxetane smoothly proceeds with high regioselectivity under 1 atm of carbon monoxide at room temperature to give the corresponding β- and γ-siloxy amides in high yields, respectively. [(R3Si)2NR1R2]+[Co(CO)4]− is thought to be an active catalyst species and directs the high regioselectivity of the carbonylation.

In situ scanning tunneling microscopy study of platinum (110) in a reactor cell at high pressures and temperatures

With a specialized version of a scanning tunneling microscope which allows us to study in situ the atomic structure of surfaces under variable pressures (ultrahigh vacuum—atmospheric) and temperatures (300–425 K), we have investigated the structures of the initially clean (110) surface of single crystal platinum while in environments of hydrogen, oxygen, and carbon monoxide. The surface in 1.6 atm of hydrogen appears to be dominated by various sizes of nested missing-row reconstructions. The surface in 1 atm of carbon monoxide, however, does not have the small scale missing-row reconstructions, but does appear to have flat terraces separated by multiple height steps. The surface in 1 atm of oxygen appears to have enlarged (111) microfacets.

Sodium tetraphenylborate as a phenylating reagent in the palladium-catalyzed phenylation of alkenes and acid chlorides

Sodium tetraphenylborate (NaBPh 4) reacts with terminal alkenes in acetic acid at 25°C in the presence of a catalytic amount of palladium(II) acetate together with silver acetate as a re-oxidant to give the corresponding phenylated alkenes in 22–87% yield. It also reacts with acid chlorides in tetrahydrofuran (THF) at 25°C in the presence of a catalytic amount of tetrakis(triphenylphosphine)palladium(0) to give the corresponding phenyl ketones in 51–100% yield. Carbonylation of the borate with 1–30 atm carbon monoxide (CO) in methanol at 25°C in the presence of palladium(II) acetate or sodium chloropalladate (Na 2PdCl 4) affords a low yield (9–30%) of benzophenone and methyl benzoate, a higher pressure favoring the formation of the latter.