Mechanism of the cobalt-catalyzed carbonylation of ethyl diazoacetate

Synthesis of Amido Esters and Amido Phosphonates through Carbonylation of Diazo Compounds Followed by Nucleophilic Addition Reaction

“…[43][44][45] Thus, if we use an organic carbonyl compound as a nongaseous CO source, we will need a separate catalyst to activate the diazo compound and yield the carbene. [47][48][49] For the initial screening of different carbonylmetal compounds, we chose commercially less expensive Co 2 (CO) 8 and Fe 2 (CO) 9 as solid CO sources. Herein, we have chosen carbonylmetal compounds as a nongaseous carbon monoxide source.…”

Carbene Radicals in Cobalt(II)–Porphyrin‐Catalysed Carbene Carbonylation Reactions; A Catalytic Approach to Ketenes

“…Carbonylation of metal–carbene species [3–6] is an interesting alternative method to produce such highly reactive ketenes, which find synthetic applications in various organic transformations. [1, 4, 5] The synthesis of medicinally important β-lactams by [2+2] ketene–imine cycloaddition reactions is especially important in this perspective.…”

“…Following the discovery of stoichiometric carbonylation reactions of Fischer-type carbene complexes, thus far only a few transition-metal-catalysed processes have been developed. [5, 6] While interesting results have recently been obtained with a noble (palladium) metal catalyst, [5c] carbene carbonylation by base-metal catalysts reported thus far were associated with low efficiencies and required quite harsh reaction conditions (elevated temperatures and high CO pressures). [6] Therefore, we focused on the development of new catalytic carbene carbonylation processes by catalysts based on abundant first-row transition metals that operate under comparably mild reaction conditions.…”

“…Since ketenes are highly reactive [5, 6] and can generally only be trapped in the presence of a strong nucleophile, we first evaluated the activity of [Co II ( P1 )] ( P1 = tetraphenylporphyrin; Figure 1) in the catalytic carbonylation of ethyl diazoacetate (EDA; 1 ) in presence of aniline ( 2a ) under 10 bar CO at 50 °C. Under these conditions, (ethoxycarbonyl) ketene was formed and trapped by aniline to produce ethyl 2-(phenylcarbamoyl)acetate ( 3a ) in 57% isolated yield (Table 1, entry 1).…”

“…[5c, 6] Given that carbon monoxide has a weak affinity for the cobalt(II) center, [14] it is unlikely for carbon monoxide to bind to the catalyst and thus influence the carbonylation of diazo compounds under the applied catalytic reaction conditions. The more nucleophilic character of C compared to Fischertype carbenes further reduces its reactivity towards nucleophiles, which is likely an important feature in preventing unwanted side-reactions.…”