Octacarbonyl dicobalt-catalyzed selective carbonylation of (trimethylsilyl)diazomethane to obtain (trimethylsilyl)ketene

Ungvári, Neszta; Kégl, Tamás; Ungváry, Ferenc

doi:10.1016/j.molcata.2004.04.018

Cited by 29 publications

(9 citation statements)

References 20 publications

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“…In addition to the C–H activation reactions, Co 2 (CO) 8 -catalyzed carbonylation of carbene precursors would lead to the formation of ketene intermediates (Scheme ). − The subsequent nucleophilic addition or cycloaddition of these ketene intermediates were similar to those in the Pd(0)-catalyzed carbene carbonylation reactions that have been discussed in section . In 2016, Lee and co-workers reported a Co(0)-catalyzed carbonylative cyclization of pyridyl diazoacetates 897 for the synthesis of pyridoisoquinolinones 898 .…”

Section: Other Transition-metal-catalyzed Carbene Couplingsmentioning

confidence: 77%

“…DFT calculations have suggested that the Pd-catalyst is not only involved in the ketene formation process but also plays a role in the [2 + 2] cycloaddition process which may affect the diastereoselectivity of the products (Scheme e). Compared with the Co 2 (CO) 8 -catalyzed or -mediated carbonylation of EDA with CO involving the formation of ketene intermediate, − the Pd-catalyzed protocol provides a general route to ketene compounds and is expected to be widely used in organic synthesis owing to the broad substrate scope of carbene precursors and the mild reaction conditions (with atmospheric pressure of CO). Later, similar transformations were also achieved under the catalysis of other transition-metal complexes. − …”

Section: Pd-catalyzed Carbene Coupling Reactionsmentioning

confidence: 99%

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Transition-Metal-Catalyzed Cross-Couplings through Carbene Migratory Insertion

2017

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Transition-metal-catalyzed cross-coupling reactions have been well-established as indispensable tools in modern organic synthesis. One of the major research goals in cross-coupling area is expanding the scope of the coupling partners. In the past decade, diazo compounds (or their precursors N-tosylhydrazones) have emerged as nucleophilic cross-coupling partners in C-C single bond or C═C double bond formations in transition-metal-catalyzed reactions. This type of coupling reaction involves the following general steps. First, the organometallic species is generated by various processes, including oxidative addition, transmetalation, cyclization, C-C bond cleavage, and C-H bond activation. Subsequently, the organometallic species reacts with the diazo substrate to generate metal carbene intermediate, which undergoes rapid migratory insertion to form a C-C bond. The new organometallic species generated from migratory insertion may undergo various transformations. This type of carbene-based coupling has proven to be general: various transition metals including Pd, Cu, Rh, Ni, Co, and Ir are effective catalysts; the scope of the reaction has also been extended to substrates other than diazo compounds; and various cascade processes have also been devised based on the carbene migratory insertion. This review will summarize the achievements made in this field since 2001.

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Section: Other Transition-metal-catalyzed Carbene Couplingsmentioning

confidence: 77%

Section: Pd-catalyzed Carbene Coupling Reactionsmentioning

confidence: 99%

Transition-Metal-Catalyzed Cross-Couplings through Carbene Migratory Insertion

2017

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“…This and an earlier discussion invites the question about the relative stability of the 1-and 2-enolates, CH 2 =CHCH=CHO − and CH 2 =C(O − ) CH=CH 2 , and indeed other conjugated and cross-conjugated species. From the enthalpies of formation of their conjugate acids 34,286 and their acidities 287 , we conclude that 1-enolate is ca 25 kJ mol −1 more stable-the corresponding neutral enols differ by very much the same value 258 . In contrast, the enthalpies of formation of CH 2 =CHCH=CHMe and CH 2 =C(Me)CH=CH 2 differ only by 6 kJ mol −1 .…”

Section: Group 9: Cobalt Rhodium and Iridiummentioning

confidence: 88%

Thermochemical Considerations of Metal Enolates

Liebman

Slayden

2010

Patai's Chemistry of Functional Groups

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Introduction Group 1: Lithium, Sodium, Potassium, Rubidium and Cesium Group 2: Beryllium, Magnesium, Calcium, Strontium and Barium Group 13: Aluminum, Gallium, Indium and Thallium Group 14: Tin and Lead Group 11: Copper, Silver and Gold Group 12: Zinc, Cadmium and Mercury Group 3: Scandium, Yttrium and the Lanthanides Actinides Group 4: Titanium, Zirconium and Hafnium Group 5: Vanadium, Niobium and Tantalum Group 6: Chromium, Molybdenum and Tungsten Group 7: Manganese and Rhenium Group 8: Iron, Ruthenium and Osmium Group 9: Cobalt, Rhodium and Iridium Group 10: Nickel, Palladium and Platinum

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“…One powerful way leading to ketene is the substitution of the diazo group in diazoalkanes by carbon monoxide. The very reactive ethoxycarbonyl ketene formed as a short living product by the carbonylation of ethyl diazoacetate (EDA) can be trapped in situ by various scavengers such as alcohols, secondary amines, and imines to obtain the corresponding malonic acid derivatives 2 or β-lactams, 3 respectively. Moreover, in the cobalt-catalyzed domino reaction of EDA with CO and ferrocenylimines the synthesis of unsaturated malonic acid derivatives was reported.…”

Section: Introductionmentioning

confidence: 99%

Density Functional Study on the Mechanism of Nickel-Mediated Diazo Carbonylation

2012

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The mechanism of diazo activation as well as the carbonylation of the resulting carbene complexes has been investigated by means of DFT calculations at the PBE0/TZVP level of theory. The free energy profile of all elementary steps of the reaction, i.e., diazo coordination, dinitrogen extrusion, carbene−CO coupling, CO coordination, and ketene elimination, have been elucidated for diazomethane and ethyl diazoacetate as substrates and for Ni(CO) 3 , Ni(CO) 2 (PH 3 ), and Ni(dtbpe)(CO) (dtbpe = 1,2-bis(di-tert-butylphosphino)ethane) as precursors. The reaction rate is determined by the formation of the coordinatively unsaturated precursor followed by the dinitrogen extrusion, regardless of the initial diazo compound and the catalyst precursor. For the homoleptic precursor Ni(CO) 3 the free energy of activation for diazomethane and ethyl diazoacetate (EDA) is 16.9 and 22.4 kcal/mol, respectively. The replacement of one carbonyl ligand with PH 3 results in a decrease in the activation barrier, modifying the energies to 15.7 and 20.5 kcal/mol, respectively. The activation free energy of the diazo extrusion step promoted by Ni(dtbpe)(CO) is 24.3 kcal/mol for diazomethane and 28.1 kcal/mol for EDA. The formation of carbene complexes is slightly endergonic starting from the homoleptic precursor and exergonic for the phosphine-substituted complex. The carbene−CO coupling, resulting in coordinatively unsaturated ketene complexes, is a fast and highly exergonic process with reaction free energies between −32.3 and −42.1 kcal/mol, depending on the substituents. Under a carbon monoxide atmosphere the ketene complexes may uptake one CO, forming coordinatively saturated ketene complexes via low barriers in exergonic reactions. The final step, i.e., the dissociation of ketene or ethoxycarbonylketene from the saturated ketene complex, regenerates the corresponding nickel−carbonyl precursor. The azine formation side reaction for the simplest case between Ni(CO) 3 and diazomethane has been also examined and found to be highly exergonic; however, the large free energy barrier prevents the formation of benzophenone-azine when CO is also present.

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Octacarbonyl dicobalt-catalyzed selective carbonylation of (trimethylsilyl)diazomethane to obtain (trimethylsilyl)ketene

Cited by 29 publications

References 20 publications

Transition-Metal-Catalyzed Cross-Couplings through Carbene Migratory Insertion

Transition-Metal-Catalyzed Cross-Couplings through Carbene Migratory Insertion

Thermochemical Considerations of Metal Enolates

Density Functional Study on the Mechanism of Nickel-Mediated Diazo Carbonylation

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