Decarbonylation of .beta.-carbomethoxypropionylpentacarbonylmanganese(I)

Casey, Charles P.; Brunsvold, William R.; Koch, James.

doi:10.1021/ic50162a054

Cited by 7 publications

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References 4 publications

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“…The title compound has been described previously, but was only obtained as an alkyl rearrangement by‐product during the decarbonylation of [Mn(COCH 2 CH 2 COOCH 3 )(CO) 5 ], which yields the expected [Mn(CH 2 CH 2 COOCH 3 )(CO) 5 ] as the main product by reverse migratory insertion. We have synthesized compound 1 , following a well‐established general procedure, by nucleophilic substitution of bromide in methyl 2‐bromopropionate by pentacarbonylmanganate, which was made in situ by reduction of [Mn 2 (CO) 10 ] with Na–K alloy, see Scheme .…”

Section: Resultsmentioning

confidence: 99%

“…In our hands, K + [Mn(CO) 5 ] – and methyl 2‐bromopriopionate gave, after chromatographic purification, a fair yield (39 %) of pure product. The spectroscopic properties of the isolated compound matched those reported in the previous contribution (see SI, Figures S1 and S2) …”

Section: Resultsmentioning

confidence: 99%

“…The spectroscopic properties of the isolated product ( 1 H NMR, FTIR in pentane) matched those previously reported by Casey et al 1 H NMR ([D 6 ]actone, δ ): 3.62 (3H, s, OC H 3 ), 2.35 (1H, q, 3 J HH = 7 Hz, MnC H ), 1.55 (3H, d, 3 J HH = 7 Hz, CHC H 3 ) [cf. 3.65, 2.31 and 1.58 ( J = 7.5 Hz) in CDCl 3 ] . The FTIR in pentane is essentially identical to the previously reported one in hexane, but previously unreported weak bands, attributed to 13 C isotopomers, are also observed in our spectrum (see Figure S2).…”

Section: Methodsmentioning

confidence: 99%

“…The spectroscopic properties of the isolated compound matched those reported in the previous contribution (see SI, Figures S1 and S2). [11]…”

Section: (A) Synthesismentioning

confidence: 99%

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Homolytic Bond Strength and Radical Generation from (1‐Carbomethoxyethyl)pentacarbonylmanganese(I)

et al. 2019

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Compound (1-carbomethoxyethyl)pentacarbonylmanganese(I), [MnR(CO) 5 ] (R = CHMeCOOMe, 1), was synthesized from K + [Mn(CO) 5 ]and methyl 2-bromopropionate and isolated in pure form. Upon thermal activation, the Mn-R bond is homolytically cleaved and the resulting 1-carbomethoxyethyl radical is able to initiate the polymerization of methyl acrylate (MA). A kinetic study of the decomposition of 1 in the presence of tris(trimethylsilyl)silane, TTMSS (10 equiv., saturation conditions) at 70, 65 and 60°C yielded the T-dependent activation rate constant, k a , which al-Scheme 1. Moderating equilibrium for a controlled radical polymerization.[a]

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

“…The spectroscopic properties of the isolated compound matched those reported in the previous contribution (see SI, Figures S1 and S2). [11]…”

Section: (A) Synthesismentioning

confidence: 99%

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Homolytic Bond Strength and Radical Generation from (1‐Carbomethoxyethyl)pentacarbonylmanganese(I)

et al. 2019

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“…Heating the solid above the melting point at 70°C gave a fairly clean conversion to Mn(CO)5Br. Heating a deuterochloroform solution at 70°C for 3.5 h gave the haloalkyl complex 11, characterized as for 11 10 by the distinctive 'H NMR spectrum. As with 10, complex 11 was partly converted back to the acyl complex on cooling overnight.…”

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The preparation and reactions of ω-bromoacylmanganese pentacarbonyls

Masters¹,

Sorensen²

1990

Can. J. Chem.

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. J. Chem. 68, 502 (1990).The reaction of o-bromoacyl chlorides Br-CH2-(CH2),-COCI and Mn(CO)5-is reported. In the case of n = 0, one obtains ketene, Mn(CO)5Br, and chloride ion. In contrast, the corresponding chloro compound gives the known chloroacyl manganese complex. With n = 1, 2 , or 3, one can isolate the corresponding w-bromoacylmanganese complexes. On mild heating, the n = 1 complex produces only ethylene and Mn(CO)5Br. The n = 2 and 3 complexes are also relatively labile on heating in THF solution and produce the 1-alkene as the major organic product. In chloroform solution, the corresponding o-bromoalkyl complex is produced initially on heating, but further heating again produces mainly the I-alkene. However, the n = 2 complex also produces appreciable amounts of cyclopropane. On a Ctudit les reactions des chlorures de o-bromoacyles (Br-CH2-(CH2),-COC1) avec le Mn(CO)5-. Dans le cas ob n = 0, on obtient du cttkne, du Mn(CO),Br et de I'ion chlorure. Par opposition, le compost chlort correspondant fournit le complexe chloroacyl mangankse connu. Lorsque n = 1, 2 ou 3, on peut isoler les complexes o-bromoacylmangankse correspondants. Lorsqu'on le chauffe ltgkrement, le complexe dans lequel n = 1 ne conduit qu'h d'tthylkne et de Mn(CO)5Br. Les complexes dans lesquels n = 2 ou 3 sont aussi relativement labiles; lorsqu'on les soumet a un chauffage, en solution dans le THF, le produit organique majeur est le 1-alckne. En solution dans le chloroforme, il y a formation des complexes o-bromoalkyles correspondants; mais, si l'on continue le chauffage, il y a principalement formation du 1-alckne. Toutefois, le complexe dans lequel n = 2 conduit a la formation d'une quantitt apprtciable de cyclopropane.Mots elks : bromoacylmangankse pentacarbonyl, pentacarbonyl manganate, tthylkne, cyclopropane.[Traduit par la revue]Acylrnanganese pentacarbonyls 1 are a very well-known class of organometallic compounds (I). The readily lose carbon monoxide to form the alkyl complex 2 and the mechanism of this reversible reaction has been elegantly determined by labelling studies (2) and supported by later theoretical calculation^ (3).A great many derivatives of 1 are known, but there has been no systematic study of cases where R = -(CH2),--CH2Br, 3, although most of the corresponding chloro compounds have been prepared. The fact that the first member of this series (n = 0) reacted in a totally different way compared to the chloro analog makes the extension to the bromo analogs non-trivial. Our interest was mainly in the fate of the organic part of these complexes when they were subjected to thermolysis, i.e., unsaturated (16eP) organometallics often add oxidatively to a C-Br bond. It was planned to study acyl system 3 where n was varied from 0 to 3. The usual route for preparing such complexes is to react the corresponding acyl halide with Mn(CO)5-salts. This reaction is in fact a very general ketene synthesis, which has been described in other publications (4). The reaction of Mn(CO)5-with acyl chlorides to give acylmanganese orga...

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