Carbon monoxide insertion into

Pyrrohdinone (2-pyrrohdone, butyrolactam or 2-Pyrol) (27) was first reported in 1889 as a product of the dehydration of 4-aminobutanoic acid (49). The synthesis used for commercial manufacture, ie, condensation of butyrolactone with ammonia at high temperatures, was first described in 1936 (50). Other synthetic routes include carbon monoxide insertion into allylamine (51,52), hydrolytic hydrogenation of succinonitnle (53,54), and hydrogenation of ammoniacal solutions of maleic or succinic acids (55—57). Properties of 2-pyrrohdinone are Hsted in Table 2. 2-Pyrrohdinone is completely miscible with water, lower alcohols, lower ketones, ether, ethyl acetate, chloroform, and benzene. It is soluble to ca 1 wt % in aUphatic hydrocarbons. 

Carbon monoxide insertion into Ni—C bonds has been postulated in carbonylation reactions involving (7r-C3H5NiX)2 (X = C1, Br, or I) (112, 123a). 

Note that carbon monoxide inserts into the Zr-H bond of 1 (2 equiv.) to afford an T -formaldehydo-type complex [(Cp2ZrCl)]2(g-CH20) [200-202]. Iminoacyl zir-conocene complexes are formed after addition of 1 to isonitriles [203]. Carbon dioxide [183, 202] is reduced to formaldehyde with 1 (2 equiv.). C02-like molecules such as isocyanates RNCO [204], isothiocyanates RNCS [205], and carbodiimides RNCNR [204] are readily converted to the corresponding bidentate form-amido ligands. 

Carbon monoxide inserts into the Sc-Ge bond of 123, leading to a scandium enedione diolate via a proposed ketene-type intermediate (Scheme 40).236... 

On the other hand, when the oxidative carbonylation of a ,a -disubstituted propynylamines was carried out in the presence of an excess of CO2, the intermediate carbamate species could undergo cyclization with incorporation of CO2 into the five-membered cycle, either by direct nucleophilic attack of the carbamate oxygen to the triple bond coordinated to Pd(II) (Scheme 33, path a) or through the intermediate formation of a palladium carbamate complex followed by triple bond insertion (Scheme 33, path b). Carbon monoxide insertion into the Pd - C bond of the resulting stereoisomeric vinylpalladium intermediates then led to the final oxazolidi-none derivatives. 

The important difference between the insertion mechanism (2.2) and the migration mechanism (2.3) is the following. In the insertion mechanism carbon monoxide inserts into the metal methyl bond and the acyl bond formed takes... 

Carbon monoxide insertion into the carbon-palladium bond of 4, followed by nucleophilic displacement with methoxide, gives a 4 1 mixture of trans and cis-dimethyl hex- endioate which is the desired l, 4-dicarbonylaton precursor to adipic acid. 

Metal Hydrides. The simplest reactions in this group are the various catalytic reduction reactions of carbon monoxide. Methane or higher hydrocarbons, methanol or higher alcohols, and a variety of other oxygenated organic compounds may be formed, depending upon the catalyst and reaction conditions (23). There is little evidence about the mechanism of these reactions, but the initial step in every example is probably a carbon monoxide insertion into a metal hydride, followed by reduction reactions. 

Many transition metal alkyls react with carbon monoxide to give acyl compounds. In all these cases the acyl derivatives can be detected at least by infrared methods and in most cases isolated. Molybdenum, manganese, rhenium, iron, cobalt, rhodium, nickel, palladium, and platinum alkyls, Grignard reagents, and boranes, all react with carbon monoxide, and one can explain the products from these on the basis of carbon monoxide inserting into the metal alkyl. 

In the second example carbon monoxide insertion into a benzothiophenylpalladium complex, and a subsequent C-H activation led to the transformation of 3-iodo-2-phenyl-benzothiophene to the tetracyclic compound shown in 5.9.9... 

Triethylsilylcobalt carbonyl was formed by Eq. (74) even under high pressures of carbon monoxide (60 atm, 200° C) so that carbon monoxide insertion into a cobalt-silicon bond does not readily occur... 

Another process to make acetic anhydride involves carbon monoxide insertion into methyl acetate (Fig. 1). 

P-Lactams. Carbon monoxide inserts into 2-bromo-3-aminopropene derivatives in the presence of a catalytic amount of Pd(OAc)2 and triphenylphosphine to give a-methylene- -lactams in 38-89% yield. Pd(acac)j can be used instead of Pd(OAc)2 with similar results. ... 

The results imply that the conjugated enallene ester system (l,2,4-alkatriene-3-carboxylate) 127 is required for incoiporation of the second molecule of carbon monoxide, and the following mechanism (Scheme 11-39) has been proposed. The formation of the palladacyclopentene 137 from 136 is suggested as an intermediate of 140. Then carbon monoxide insertion into the palladacycle 137 generates the acylpalladium 138. Subsequent reductive elimination affords the cyclopentenone 139, which isomerizes to give the cyclopentenone 140 as a final product. 

Carbon monoxide inserts into metai-cariion iionds... 

The probable catalytic cycle for the carbonylative coupling reaction involves oxidative addition, carbon monoxide insertion into the R-Pd complex, transmetala-tion, tran -cw-isomerization, and reductive elimination. 

Carbon monoxide insertion into the copper-alkyl bond is indirectly shown by reaction of CO with dibutylcuprate(I), an anionic dialkyl derivative of dicoordinated copper(I). The product of the reaction, dibutylketone, may be rationalized by assuming carbon monoxide coordination to the anionic copper complex, followed by alkyl migration to the unstable anionic complex Cu[C(0)Bu](Bu) , with subsequent reductive elimination to the observed organic product. 

Carbon monoxide insertions into palladium-alkyl or palladium-aryl bonds were extensively studied in connection with the palladium-catalyzed CO-olefin copolymerization process . 

Pyridine-2-carboxylato (pyca) derivatives of palladium(II) have been found to undergo carbon monoxide insertion into the palladium-methyl bond ... 

Carbon monoxide insertion into an iridium-methyl bond has been reported for an >j -indenyl compound of iridium(III), Ir(/7 -C9H7)Me2(PMe3)(CO)2- In the presence of one equivalent of trimethylamine oxide, used as a carbon monoxide scavenger, carbon monoxide insertion occurs with a simultaneous increase in the hapticity of the indenyl ligand ... 

Carbon monoxide insertion into an osmium-carbon bond of a trinuclear cluster has been reported to give a cluster containing a t-ketene ligand ... 

The first reversible carbon monoxide insertion into the manganese-carbon bond of MnMe(CO)5 and MnPh(CO)5 ... 

The elements of groups VA and IVA are characterized by a high affinity for oxygen as donor atom. Frequently encountered is the t) -acyl arising from carbon monoxide insertion into the metal-carbon a bond. Section 11.3.2.1.5 described similar molyb-denum(II) acyl derivatives. 

Carbon monoxide insertion into the tantalum-methyl bonds of a tetramethyl derivative of tantalum(V), Taf j -CsMesjMe, reportedly" gives the following >j -acetone complex ... 

Carbon monoxide insertion into the phenyl-titanium bond of Ti(j7 -C5H5)2Ph2 yields benzophenone. ... 

Carbon monoxide insertion into zirconium(IV)-silicon bond has been reported . The trimethylsilyl derivative Zr(/7 -C5H5)2(SiMe3)Cl was carbonylated under CO pressure (about 7 atm) in diethyl ether, giving the following silyl-acyl compound ... 

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