Carbonyl insertion products

Mo(PhNNNPhXCO)4] prepared from Mo(CO)g and Na[PhNNNPh] in boiling 1,2-dimethoxyethane, can be isolated as its tetramethylammonium salt 118). The complexes Mo(ArNNNArXC5HjXCO)2 have been obtained from MoC1(CsH5XCO)3 and Na- or K[PhNNNPh] 58,118), ArNNNAr-SnMej (7), Ag(ArNNNAr) 179), or ArNNNHAr/py (777). A carbonyl insertion product (11) has also been isolated from the reaction of... 

Carbonylation of the three-coordinated cationic palladium(II) complex of reaction (j) gives the carbonyl complex, which is an intermediate of the subsequent carbonyl inserted product ". ... 

In contrast, when allowed to react with Rh(CO)(PPh3)2(OTf) at 60-65°C, cyclopropenone forms cationic complex 17, in which cyclopropenone is bound to rhodium through the oxygen atom instead of the C-C double bond. Further heating at 60-65°C leads to the formation of the metal carbonyl insertion product 18 [34]. In refluxing benzene, 18 decomposes to diphenylacetylene and Rh(CO)(PPh3)2(OTf). 

The carbonylation of orj/to-palladated acetophenonephenylhydrazone yields an isoindolinone derivative 7.49, which is of the same type as the methyleneisoindoli-none 7.44 in Scheme 7.6 [62]. However, the addition of a stoichiometric amount of NaOMe to the carbonyl inserted product 7.48 in solution leads instantaneously to reductive elimination, yielding the indazole derivative 3-methyl-1-phenyl-indazole 7.50 in a high yield. This process is presumed to proceed by complete deprotonation of the carbonyl coordinated product 7.48, followed by ElZ isomerization with reductive elimination, as shown in Scheme 7.7 [63]. 

N-benzylaniline with phosgene, and then with sodium azide to produce carbonyl azide 52. On heating, nitrogen is evolved and a separable mixture of nitrene insertion product 53 and the desired ketoindazole 54 results. The latter reaction appears to be a Curtius-type rearrangement to produce an N-isocyanate (54a), which then cyclizes. Alkylation of the enol of 54... 

Efforts to realize an intramolecular version of the above reactions met with limited success when monocyclic 4-thio-substituted (3-lactams were used. Cu(acac)2-catalyzed decomposition of diazoketone 358 produced the epimeric carbapenams 359 a, b together with the oxapenam derivative 360 341 these compounds correspond to the C4/S insertion products obtained in intermolecular reactions. Oxapenams were obtained exclusively when the acrylate residue in 359 was replaced by an aryl or heteroaryl substituent 275 342). The different reaction mode of diazoketones 290a, b, which furnish mainly or exclusively carbonyl ylide rather than sulfur ylide derived products, has already been mentioned (Sect. 5.2). 

A3-Pyrroline formation with carbonyl insertion also occurs during the reaction of /V-sulfinylarylamines with diphenylcyclopropenone in the presence of nickel carbonyl (Scheme 36).64 Phenyl isocyanate does not give a pyrroline product under these reaction conditions, hence the SO-CO exchange probably occurs within an intermediate metallocycle. The reaction... 

Besides direct carbonylation, insertion of acetylene and of other molecules and groups into C—Ni bonds is possible. A variety of linear or cyclic products results. Thiourea proved an exceedingly efficient ligand (180). 

Following the precedent set by Green,77 the reaction is assumed to proceed through the i73-vinylcarbene complex 70, which is formed by the protonation of the CHPh carbon of 68. This then undergoes carbonyl insertion to afford the 16-electron complex 71, whose coordination sphere is subsequently saturated by iodide, affording the i74-vinylketene product (67). 

In contrast to 2-alkylarylcarbenes, triplet carbonyl carbenes do not abstract H from 5- or e-CH bonds. Photolysis of diazo compounds (7) in methanol gave products due to Wolff rearrangement (8) and 0-H insertion (9). Sensitized photolysis led, in addition, to the H-abstraction product (10). Analysis of the results indicated that a large proportion of the insertion product (9) arises from the excited diazo compound and that spin inversion of the triplet carbene is faster than H-abstraction from the solvent. Intersystem crossing to the singlet state is a major reaction of all triplet carbonyl carbenes that are not rapidly scavenged intramolecularly. 

Vaska s complex catalyzed the transformahon of aUenylcyclopropane into 2-alkenylidenecyclohex-3-enone under conditions of pressurized CO (Scheme 11.25) [38]. In this reaction, the jr-coordination to internal oleflnic moiety of the aUene brings the metal closer to the cyclopropane ring. Release of the cyclopropane ring strain then facilitates the oxidative addition of vinylcyclopropane moiety along with C-C bond cleavage, such that metallacyclohexene is obtained a subsequent carbonyl insertion and reductive elimination then provides the product Hence, the reaction can be recognized as a [5+1] cycloaddition of vinylcyclopropane and CO. 

Sarel and co-workers have examined some reactions of alkynylcyclopropanes with iron carbonyl compounds [1]. Treatment of cyclopropylacetylene (5) with iron pentacarbonyl under photolytic conditions gives, after cerium(IV) oxidation, isomeric quinones 6 and 7, derived from two molecules of 5 and two carbonyls with both cyclopropane rings intact [6]. Furthermore, the photoreaction of dicyclopropylacetylene (8) with iron carbonyl gives some ten different products depending on the reagents and the reaction conditions, and some of them have the cyclopentenone skeleton formed by the opening of cyclopropane ring coupled with carbonyl insertion [7] (Scheme 2). 

Cycloproparenes do not form metal complexes with all transition metals. Reaction of cyclopropabenzene with diiron-nonacarbonyl yields polymer, while reaction with cyclopropanaphthalene leads to a stable product formed by metal and carbonyl insertion. Attempts to form cycloproparene-chromium complexes have also failed. ... 

Upon the addition of Lewis (i.e. All ) and protonic non-compSexing. acids (i.e. HPF5) promoters to [Ru(00)3X3] catalysts, improvements in selectivity to valuable products (acetic acid + ethyl acetate) and in reaction rate are observed. This is believed to be due to an acceleration by acids of the alkyl migration-carbonyl insertion step of the process, as discussed in detail in a recent paper (10). 

Dormond ef rrZ. have exploited compounds 30 and particularly 32 as synthetically useful reagents. The uranium-mediated methylenation of carbonyl compounds (cf.. the Wittig, Peterson or Tebbe reactions) is illustrated in Equation (5.1). The instantaneous formation under ambient conditions of the insertion product 33 was essentially quantitative (e.g./ =... 

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