Carbonyl Insertion Research Articles

Synthesis of Cyclometalated Rhodium(III) Complexes. Study of the Carbonyl Insertion Reactions into the Rh-C Bond of the Metalocycle

Abstract In this paper we report the preparation of new orthometalated rhodium(III) compounds of the formula Rh(oq)(AB)(PC), from Rh(oq)(Br)(PC)(H20), AB being a bidentade anionic ligand, oq= 8-oxyquinolate and PC = P(o-C6F4)Ph2. Their redox behaviour is also described. The reaction of Rh(Oq)(Br)(PC)(H20) [Oq = 5-Me-8-oxyquinolate (5-Meoq), 8-oxyquinolate] with carbon monoxide under pressure leads to expansion of the metalocycle ring by CO insertion into the Rh-C bond.

Hydrozirconation of ( E)-3-methoxy-1-phenyl-1-propene and ( E)-3-phenyl-2-propenol

Hydrozirconation-deuterolysis of ( E)-3-methoxy-1-phenyl-1-propene was found to give α- and ω-deuterated propylbenzenes after elimination of the ether function. An unforeseen higher degree of benzylic substitution in the propylbenzenes was observed. In an effort to account for the regiochemical outcome of the reaction, hydrozirconation of propenylbenzenes with mixed reagents and deuterozirconation was investigated. Hydrozirconation of ( E)-3-propenol-2-propenol results in loss of the hydroxyl group to only a small extent, and after hydrozirconation and deuterolysis fair yields of benzenopropan-γ- d-ol are formed. Carbonyl insertion into 3-hydroxyl-1-phenyl-1-zirconocene-propane gives low yields of the lactone dihydro-3-phenyl-2(3 H)-furanone.

ChemInform Abstract: Insertion of Iron Carbonyl into a C‐S Bond of Tetrathiofulvalene.

AbstractThe complex (III), obtained by ring‐opening of (I) adjacent to an internal double bond crystallizes in the space group Cc with Z=4.

Insertion of iron carbonyl into a CS bond of tetrathiofulvalene

Irradiation of a mixture of tetrathiofulvalene (TTF) and iron pentacarbonyl in THF gives a dinuclear hexacarbonyl iron chelate, Fe 2(CO) 6[μ-SC( CSCHCHS )SCHCH] ( 1), by ring-opening of TTF adjacent to an internal double bond. The donated ligand electrons originate from an sp 2 carbon atom, a sulphur atom, and a carbon—carbon double bond.

ChemInform Abstract: Steroidal A Ring Aryl Carboxylic Acids: A New Class of Steroid 5α‐Reductase Inhibitors.

AbstractThe 17β‐carbamoylestratriene‐3‐carboxylate (VIII) is prepared from estrone (I) by sequential introduction of carboxylate‐derived moieties at C‐3 and C‐17 using palladium(0) catalyzed carbonyl insertion.

Solvent and nucleophile effects on the carbonyl insertion reaction into metal—carbon bonds

The rate constant, k 3 , for the direct insertion of carbon monoxide induced by tertiary phosphines into [(η 5 -C 5 H 5 )(CO) 3 MoCH 2 C 6 H 5 ] in toluene solution decreases steadily with increasing cone angle of the phosphine. In contrast, for [(CO) 5 MnCH 2 C 6 H 5 ], k 3 increases with decrease in the Tolman electronic parameter, v , of the phosphine (i.e., with increasing electron donation) and does not correlate with the cone angle. However, k 3 reflects the size of the phosphine to a greater degree as the size of the benzyl substituent on manganese increases. An analysis of k 1 values in the solvent-assisted insertion pathway has been made for both the molybdenum and manganese systems in THF, 2-MeTHF and 2,5-Me 2 THF solutions. The general decrease in k 1 with increasing size of the solvent for the cyclopentadienyl-molybdenum system becomes less marked as the size of the benzyl substituent increases. The manganese complexes are relatively less sensitive to solvent size. A comparison has been made between the nucleophilic role of a solvent molecule in the k 1 step and that of a tertiary phosphine in the k 3 step.

The Reactions of Alkynlcyclophosphazenes with Metal Carbonyls

Abstract The reaction of N3P3F5C≡CR (R=Ph, Me3Si, n-C4H9) with CO2(CO)8, leads to N3P3F5C≡CR·CO2 (CO)6. The corresponding reaction with 2,2-N3P3F4,(C≡CPh)2, produces the novel, structurally characterized, tetracobalt species 2,2-N3P3F4 C≡CR·CO2 (CO)6)2. In the case of the previously reported N3P3F5C≡CPh complex, we now report that reaction with excess phosphazene leads to the cyclotrimerized material 1,2,4-(N3P3F5)3Ph3C6(I). Detailed dynamic 19F NMR spectroscopy studies of this material shows detectable barriers to rotation about the phosphorus-carbon bond of the central arene. The reaction of a more reactive catalyst, η5-C5H5Co(CO)2, with N3P3F5 C≡CPh gives rise to a variety of cyclooligomerized products. A cyclodimerized material, (N3P3F5)2Ph2C2(II) is isolated as the colbalt stabilized entity II·CoCp. The carbonyl insertion product of the cyclodimerized complex has been isolated as well as I and its colbalt complex I·CoCp (which is believed to contain an η4 arene). The reaction of Fe(CO)5, with N3P3F5C...

Stereospecific, sequential carbonyl insertion and extrusion reactions. Preparation and characterization of arsine iron complexes [Fe(diars)(L.alpha.)(CO)2(CH3)]+ and [Fe(diars)(L.alpha.)(L.beta.)(CO)(C(O)CH3)

A series of σ-alkyl octahedral Fe(II) complexes, of the form [Fe(diars)(CO) 2 (L α )(CH 3 )] + (diars=o-phenylenebis(dimethylarsine)) was stereospecifically prepared by thermal extrusion of carbon monoxide from the corresponding acyl derivatives. Migratory carbon monoxide insertion in the presence of a second phosphorus ligand, L β , afforded the isosteric acyl complexes [Fe(diars)(CO)(L α )(L β )(C(O)CH 3 )] +

Novel synthesis of pyrrolidinones by cobalt carbonyl catalyzed carbonylation of azetidines. A new ring-expansion-carbonylation reaction of 2-vinylazetidines to tetrahydroazepinones

Pyrrolidinones can be synthesized in high yields and regioselectivity by the cobalt carbonyl catalyzed carbonylation of azetidines. For 2-substituted azetidines (alkyl, aryl, CH 2 OH, CH 2 OR, CH 2 OCOR, and COOR), carbonyl insertion occurs in the more or less substituted ring carbon-nitrogen bond depending on the kind of substituent group and on the reaction temperature. In the case of 2-vinylazetidines, ring expansion and crbonylation affords seven-membered-ring tetrahydroazepinones. Good functional group tolerance was observed in these reactions

Synthesis and properties of η 5-C 5R 5Fe(CO) 2(CH 2) 3Si(OCH 3) 3 (R = H or Me). An example of electrooxidative-induced carbonyl insertion

Propyltrimethoxysilane compounds of the type η 5-C 5R 5Fe(CO) 2(CH 2) 3Si (OCH 3) 3 (R = H ( 3); R = Me ( 4)), can be conveniently prepared by reaction between the anionic complexes M +[η 5-C 5R 5Fe(CO) 2] − (M + = K + or Na +, R = H ( 1); M + = Na +; R = Me ( 2)) and Cl(CH) 2) 3Si(OCH 3) 3 in THF. Triphenylphosphine reacts with complex 3 in refluxing acetonitrile, to give the carbonyl insertion product η 5-C 5H 5(CO)(PPh 3)FeC(O)(CH 2) 3Si(OCH 3) 3 ( 5). Complex 4 behaves in a very different way in carbon monoxide insertion induced by triphenylphosphine. The oxidation of complexes 3 and 4 in acetonitrile have been studied by a combination of electrochemical and spectroscopic techniques. The results indicate migratory insertion oxidation of complexes 3 and 4, which is very rapid at room temperature and seems to be accompanied by nucleophilic attack by the solvent. If the reactions are carried out in the presence of triphenylphosphine, the carbon monoxide-insertion reaction is induced by this phosphorus ligand only in the case of complex 3.

Carbomolybdate clusters formed by carbonyl insertion into molybdenum-oxygen bonds. Structural investigation of the [RMo 4O 15X] 3− core (R  C 9H 4O, X  OCH 3; R  C 14H 10, X  C 7H 5O 2; R  C 14H 8, X  OH)

[C 4H 9) 4N] 2[Mo 2O 7] reacts with a variety of organic species containing α-diketone groups to give tetranuclear complexes of general composition [RMo 4O 15X] 3−. The complexes [(C 4H 9) 4N] 3[(C 9H 4O)Mo 4O 15(OCH 3)] ( I), [(C 4H 9) 4N] 3[(C 14H 10)Mo 4O 15(C 6H 5CO 2)] ( 11) and [(C 4H 9) 4N] 3[(C 14H 8)Mo 4O 15(OH)] ( III) were synthesized from the reactions of dimolybdate with ninhydrin, benzil and phenanthraquinone, respectively. Complex II may also be prepared from dimolybdate and benzoin in acetonitrile-methanol solution, from which it co-crystallizes with the binuclear species [(C 4H 9) 4N] 2[Mo 2O 5(C 6H 5C(O)C(O)C 6H 5) 2] · CH 3CN · CH 3OH ( IV). Complexes I–III exhibit the tetranuclear core, previously described for the α-glyoxal derivatives [(C 4H 9) 4N] 3[(HCCH)Mo 4O 15X], where X  F − or HCO 2 −. The ligands may be formally described as diketals, formed by insertion of ligand carbonyl subunits into molybdenum-oxygen bonds. The structures I–III differ most dramatically in the identity and coordination mode of the anionic ligand X − which occupies a position opposite the diketal moiety relative to the [Mo 4O 11] 2+ central cage. Thus, I exhibits a doubly bridging methoxy group in this position, while II possesses a benzoate ligand with an unusual μ 3-O,O′coordination mode. Complex III presents a hydroxy-group unsymmetrically bonded to three of the molybdenum centres. The stereochemical consequences of the various coordination modes are discussed. Crystal data: Compound I, monoclinic space group Pc, a = 24.888(2), b = 12.897(3), c = 24.900(3) Å, β = 101.94(2)°, D calc = 1.28 g cm −1 for Z = 4. Structure solution and refinement based on 8695 reflections with F o ⩾ 6σ(F o) (Mo- K α , λ = 0.71073 Å) converged at a conventional discrepancy factor of 0.060. Compound II, orthorhombic space group Pbca, a = 20.426(6), b = 26.916(6), c = 32.147(7) Å, V = 17673.2(20) Å 3, D calc = 1.33 g cm −3 for Z = 8; 5224 reflections, R = 0.076. Compound III, tetragonal space group I4 1/ a, a = b = 48.129(6), c = 13.057(2) Å, V = 30246.2(12) Å 3, D calc = 1.35 g cm −3 for Z = 16; 5554 reflections, R = 0.053. Compound IV, orthorhombic space group Pnca, a = 16.097(4), b = 16.755(4), c = 25.986(7) Å, V = 7008.1(13) Å 3, Z = 4, D calc = 1.18 g cm −3 ; 2944 reflections, R = 0.061.

Polyoxomolybdate-o-benzoquinone interactions. Synthesis and structure of a diacetal derivative, [Mo4O15(OH)(C14H8)]3-, from 9,10-phenanthrenequinone carbonyl insertion. Comparison to the reaction products with tetrachloro-1,2-benzoquinone, the ligand-bridged binuclear complexes [(MoO2Cl2)2L]2-, L = (C6Cl2O4)2- and (C2O4)2-, formed via carbonyl insertion and chloride transfer

Polyoxomolybdate-o-benzoquinone interactions. Synthesis and structure of a diacetal derivative, [Mo4O15(OH)(C14H8)]3-, from 9,10-phenanthrenequinone carbonyl insertion. Comparison to the reaction products with tetrachloro-1,2-benzoquinone, the ligand-bridged binuclear complexes [(MoO2Cl2)2L]2-, L = (C6Cl2O4)2- and (C2O4)2-, formed via carbonyl insertion and chloride transfer

ChemInform Abstract: Potential Energy Profile of a Full Catalytic Cycle of Olefin Hydrogenation by the Wilkinson Catalyst.

It is only in the last few years that for elementary reactions of organotransition-metal compounds the transition-state geometry can be optimized and the potential energy profile can be obtained from ab initio molecular orbital calculations. Elementary reactions thus studied include oxidative addition/reductive elimination, olefin insertion/..beta..-elimination carbonyl insertion, thermolysis of ketene complexes, and isomerization of metallacycle to an alkylidene-olefin complex. Despite such success, a study of an entire cycle of a catalytic process, consisting of several elementary reactions, has been a challenge to theoreticians. The authors communicate here the results of the first such study, on homogeneous olefin hydrogenation by the Wilkinson catalyst. They concentrate on the dominant catalytic cycle of the mechanism proposed by Halpern. The model of the cycle they adopted, consists of oxidative addition of H/sub 2/, coordination of ethylene, ethylene insertion, isomerization, and reductive elimination of ethane.

Carbonyl insertion into a CS bond and complex dimerization during reaction of the dithioesters SC(Me)SEt and SC(Ph)SMe with iron carbonyl complexes

Dithioesters react with pentacarbonyliron or nonacarbonyldiiron under UV irradiation to give three classes of compounds. In the metalmetal-bonded complexes [Fe 2(CO) 6{;SC(R 1)SR 2};] (R 1  Me or Ph; R 2  Et or Me) which belong to the first class, the iron atoms are doubly-bridged by a CS unit and the original bicovalent sulphur atom of the intact dithioester unit. Similar metal links also exist in the complex [Fe 2(CO) 6{;μ-η 2-S CS(CH 2) 2S - S,S′};]( Fe-Fe) (I), formed from a trithiocarbonate (R 1R 2  SCH 2CH 2) and [Fe(CO) 5], as confirmed by single-crystal X-ray diffraction. The nature of the bonding in the second class of compounds was established by determining the crystal structure of the dimeric compound [Fe(CO) 3{;SC(Ph)SMe};] 2 (V) in which there is no metal-metal bond but each coordinated ligand forms a non-symmetrical dative sulphur-metal bond to the other iron atom. An X-ray crystal structure of a member of the third type of compound [Fe 2(CO) 6{;SC(R 1)C(O)SR 2};] (R 1  Ph; R 2 7z.dbnd; Me) (VI), shows that it is the result of carbonyl insertion into the C-SR 2 bond of the ligand.

Palladium-catalyzed carbonyl insertion route to pyrido[2-1-b]quinazoline derivatives

Insertion de CO en presence de complexes de palladium dans des [bromo-2' isopropyl-4' anilino]-2 pyridines substituees en 5

Potential energy profile of a full catalytic cycle of olefin hydrogenation by the Wilkinson catalyst

It is only in the last few years that for elementary reactions of organotransition-metal compounds the transition-state geometry can be optimized and the potential energy profile can be obtained from ab initio molecular orbital calculations. Elementary reactions thus studied include oxidative addition/reductive elimination, olefin insertion/..beta..-elimination carbonyl insertion, thermolysis of ketene complexes, and isomerization of metallacycle to an alkylidene-olefin complex. Despite such success, a study of an entire cycle of a catalytic process, consisting of several elementary reactions, has been a challenge to theoreticians. The authors communicate here the results of the first such study, on homogeneous olefin hydrogenation by the Wilkinson catalyst. They concentrate on the dominant catalytic cycle of the mechanism proposed by Halpern. The model of the cycle they adopted, consists of oxidative addition of H/sub 2/, coordination of ethylene, ethylene insertion, isomerization, and reductive elimination of ethane.

ChemInform Abstract: Thermochemical Study of the Lewis Acid Promoted Carbonyl Insertion Reaction

ChemInform Abstract: Thermochemical Study of the Lewis Acid Promoted Carbonyl Insertion Reaction

非経験的分子軌道法を用いた遷移金属触媒反応機構の解明

Recent theoretical studies on reactions of organotransition metal complexes will be reviewed, in which the structures of transition states as well as reactants and products have been optimized with the ab initio molecular orbital energy gradient method. Those studies have covered the elementary organometallic reactions such as oxidative addition/reductive elimination, olefin insertion/β-hydrogen elimination, carbonyl insertion, thermolysis of ketene complex, isomerization of metallacycle to an alkylidene-olefin complex and methylidene migratory insertion into an M-H bond. In addition, as a combination of a series of elementary organometallic reactions, the potential energy profile of a full catalytic cycle of olefin hydrogenation by the Wilkinson catalyst has been obtained.

Thermochemical study of the Lewis acid promoted carbonyl insertion reaction

Etude de la reaction de H 3 CC(O)-Mn(CO) 5 avec 1/2 Al 2 Br 6 dans une solution de toluene a 25°C; formation d'un compose d'addition. Mesure des chaleurs de reaction. Le role du metal de transition dans la determination des forces des liaisons semble mineur

Mechanism of carbonyl insertion reaction of palladium and platinum complexes. An ab initio MO study

The carbonyl insertion reaction of Pd(CH/sub 3/)(H)(CO)(PH/sub 3/), 1, and Pt(CH/sub 3/(H)(CO)(PH/sub 3/), 3, has been studied by means of the ab initio MO method with the energy gradient. The transition state has been determined for the reaction of both 1 and 3, which shows unequivocally that the reaction proceeds via methyl group migration. The reaction of 1 has a lower activation energy and is less endothermic than that of 3. These differences can be ascribed to the difference of M-CH/sub 3/, M-CO, and M-COCH/sub 3/ bond strengths between the Pd and the Pt complexes, those in the Pt complexes being stronger than in the Pd complexes. Substitution by an electron-withdrawing fluorine on the alkyl group makes the metal-alkyl bond stronger and the activation barrier higher. An electron-releasing methyl substitution gives a reverse effect. A stronger trans effect makes the metal-carbon bond weaker to give a lower activation barrier.