Carbon monoxide insertions

The kinetics of the carbonylation and decarbonylation reactions in the manganese system 

Decarbonylation of metal acyls can lead to isomerized alkyl complexes. Thus [IrCI(CO)(cyclo-octene)2]2 reacts with RCOCl to give [IrRCl2(CO)2]2, in which R may have isomerized, but this results from subsequent reversible -eliminations rather than from the decarbonylation step itself.  

An MO treatment of the CO insertion reaction has been carried out to evaluate the geometric aspects of the conversion of [MnMe(CO)g] into [Mn(MeCO)(CO)4]. Other aspects of CO insertion have also been tackled, i.e. the possible involvement of dinuclear mechanisms, solvent effects, which can be considerable, possible CHO formation from the hydride, size effects of the migrating group, the effect of the other ligands, etc. The treatment does not seem to require any fundamental modification of empirically derived views of the reaction. 

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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. 

A simplified mechanism for the hydroformylation reaction using the rhodium complex starts by the addition of the olefin to the catalyst (A) to form complex (B). The latter rearranges, probably through a four-centered intermediate, to the alkyl complex (C). A carbon monoxide insertion gives the square-planar complex (D). Successive H2 and CO addition produces the original catalyst and the product ... 

Insertion Reactions of Transition Metal-Carbon -Bonded Compounds I Carbon Monoxide Insertion... 

II. Carbon Monoxide Insertion. General Considerations and Background... 

CARBON MONOXIDE INSERTION. GENERAL CONSIDERATIONS AND BACKGROUND... 

Carbon monoxide insertion reactions may be represented by the equation ... 

Carbon monoxide insertions are intramolecular. It therefore follows that an important requirement for occurrence of these processes is presence of the CO and R in the reacting complex in a suitable position to combine. Accordingly, compound (I) does not react with CO under ambient conditions (105). The dinuclear [MeCo(DH)2]2 (DH = dimethylglyoximate) reacts with CO, but not by insertion, to give (II) in solution (125). Forma-... 

Carbon monoxide insertion is not restricted to transition metal-carbon bonds, although M—C is by far the most common substrate involved. Reactions have also been reported which lead to insertion of CO into M—O (114) and M—N (199) bonds. 1,1-Additions of M—H (27, 114) and M—M (104) linkages to CO have been postulated, too. However, direct replacement of CO, without rupture of the W—H bond, is indicated for the reaction between CpW(CO)3H (or -D) and PPhj (5) ... 

This chapter is concerned initially with kinetic results and mechanistic interpretations of the CO insertion (Section III) and extrusion (Section IV) reactions. A discussion of the stereochemical data follows (Section V), and a comprehensive survey of these reactions by the triads (Section VI) rounds out the review. Carbon monoxide insertion reactions were discussed in 1967 by Basolo and Pearson (21). Since then they have been mentioned in several reviews (49, 118, 203, inter alios) but have not been treated comprehensively. 

Again, this aspect of carbon monoxide insertion has not received much attention. Hart-Davis and Mawby (108), in a comparative study, examined the reaction of 7r-C9H7Mo(CO)jMe (VII) with various P donor ligands. They find that, in THF, (VII) undergoes CO insertion, via a solvent-assisted... 

The intermediate M(COR) is the same as that for carbon monoxide insertion. It may be a coordinatively unsaturated solvated or unsolvated a-acyl or, alternatively, a 7r-acyl. It is of interest that photolysis of MeCOMn(CO)j in an Ar matrix at 15°K produces what appears to be a trigonal bipyramidal (Cj ) MeCOMn(CO)4 209). 

For the recently reported carbon monoxide insertion reaction (94)... 

A complete description of stereochemistry of the carbon monoxide insertion and decarbonylation requires knowledge of configurational changes at the metal and a-carbon. Calderazzo and Noack (54) showed that the optical activity of the equilibrium mixture... 

Carbon monoxide insertion reactions of CpFe(CO)LR are not common. The complex CpFe(CO)(PPh3)Me can be converted to the acetyl monocarbonyl with CO in refluxing petroleum ether ( 100°C) (227). By contrast, ultraviolet light-promoted reaction between CpFe(CO)(PPh3)R (R = Ph orp-CfiH4F) and CO yields CpFe(CO)2R (188). 

Carbon monoxide insertion and decarbonylation reactions of rhodium complexes have been studied mainly in the context of investigations concerned with catalysis. 

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