Alkoxy carbonyl complexes

Rivetti, F. Romano, U. Alkoxy carbonyl complexes of palladium and their role in alcohol carbonylation. J. Organomet. Chem. 1979, 154 (3), 323-326. 

Thus the hard oxygen bases react more readily with metal carbonyls than the softer bases. Alkoxide ions attack coordinated carbon monoxide to form alkoxy carbonyl complexes. This reaction (Eq. 2-75) has been observed for many complexes of the metals Mn, Re, Ee, Ru, Os, Co, Rh, Ir, Pd, Pt, and Hg. 

ArNHC02Me) as the major product, with ureas as the main by-products. Without the metal carbonyls, the aromatic nitro compounds are recovered unchanged from the reaction. A nitrene-alkoxy-carbonyl complex was suggested as the intermediate of the reactions... 

Alkoxy-carbonyl complexes 14 are unexpectedly formed in the reactions of the bis-carbonyl ruthenium(ii) derivative 13, containing a tethered olefinic side chain, with sodium alkoxides (Equation (3)), the process involving the addition of the alkoxide anions to one coordinated carbonyl ligand. ... 

Molybdenum, tris(phenylenedithio)-structure, 1,63 Molybdenum alkoxides physical properties, 2,346 synthesis, 2,339 Molybdenum blue liquid-liquid extraction, 1,548 Molybdenum cofactor, 6,657 Molybdenum complexes acrylonitrile, 2,263 alkoxides, 3,1307 alkoxy carbonyl reactions, 2,355 alkyl, 3,1307 alkyl alkoxy reactions, 2,358 alkyl peroxides oxidation catalyses, 6,342 allyl, 3,1306... 

Tungsten complexes, 3, 973-1015 alkoxy carbonyl reactions, 2, 355 alkyl alkoxy reactions, 2, 358 amides... 

Finally the new ylides stabilized with sulfinyl but alkoxy carbonyl groups also behave in a more complex manner than for the simple sulfinyl ylide and the loss of both PhjPO and PhjP is observed [131]. Mixtures of products are obtained among which are alkenyl sulfides as major products but also sulfides and thioesters (Scheme 35). 

SCHEME 8. Schematic representation for the chelate-controlled addition of an organometaUic reagent (M—R) to the carbonyl group of a chiral a-alkoxy carbonyl compound (17). Two diastere-omers 18 with different orientation of R with respect to CH2R can be obtained. The syn diastereomer is obtained when the nucleophihc attack of R takes place on the same face of the plane, defined by the carbonyl group and the R-substituted carbon atom, where CH2R is located in the chelate complex... 

The interaction of carbon monoxide with palladium salts produces under rela tively mild (but rigorously anhydrous) conditions such species as [Pd(CO)Cl2 ] 2, [Pdj CU(CO)j and probably, under higlier carbon monoxide pressure, species such as Pd(CO)2 CI3. Only under severe conditions are reduced species such as [Pd(CO)Xlrt X = Br. Cl formed, but since the catalytic reaction is carried out under a relatively mild carbon monoxide pressure, it is rather improbable that such reduced species are present in considerable amounts. For a general discus sion of the mechanism, however, the characteri .ation of the exact nature of the palladium(Il) carbonyl complexes formed m sint is irrelevant, ( nerally speaking, carbon monoxide coordination to a Pd(U) ion will produce a facile nucleophilic attack on CO by the alcohol. The question of whether such an attack is produced by free alcohol or by a palladium bonded alkoxy group, is worth examination. 

By reaction of cationic carbonyl complexes with lithium carbanions, neutral acyl complexes are prepared. Whereas treatment of [> -CpFe(CO)3]BF4 with (a) PhLi gives the expected > -CpFe(CO)2 [C(0)Ph] in 80% yield, with (b) MeLi only traces of > -CpFe(CO)2 [C(0)Me] can be detected . This complex and other phosphane-substituted acyl compounds of the type f -CpM(CO)L[C(0)Me] [M = Fe, Ru L = CO, PPh3, P(hex)j], as well as >/ -CpMo(CO)2P(hex)3[C(0)Me] (prepared by different routes), are protonated with and alkylated with [R3 0]BF4 reversibly, yielding cationic hydroxy- and alkoxy(methyl)carbene complexes, respectively . The formation of the ( + )- and ( —)-acetyl complex / -CpFe(C0)(PPh3)[C(0)Me] from the ( + )-and ( —)-conformers of optically active > -CpFe(C0XPPh3)[C(0)0-menthyl] and MeLi occurs with inversion of configuration at the asymmetric iron atom . 

Butane, 2,3-0-isopropylidene-2,3-dihydroxy-l,4-bis(diphenylphosphino)-rhodium complexes asymmetric hydrogenation, 251 Butane-2,4-dione, l,l,l-trifluoro-4-(2-thenoyl)-in uranium ore processing, 910 2-Butanone, 4-alkoxy-carbonylation... 

The reaction of 16-electron carbonyl complexes of Pd and Pt with alcohols and amines may presumably proceed without metal-alkoxy or metal-amide bond formatiom (cf. Scheme 8.5). The reaction of alkoxymetal complexes with carbon monoxide offers an interesting mechanistic diversity (Scheme 8.13). 

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