Allyl Carbonyl Complexes

On reaction with PMcs, fCpRe(CO)(NO)Me] undergoes a reversible conversion to [(77 -Cp)Re(CO)(NO)Me(PMe3)2]. The analogous compounds [( -Cp)-Re(CO)(NO)Me(dmpe)] and [( -Cp)Re(C0)(N0)(CH20H)(PMe3)2] have also been prepared.  

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Similarly many other ij -allyl carbonyl complexes convert to ij -allyl complexes with loss of I CO. 

In 1965, Murdoch described the synthesis of a series of halo-bridged allyl carbonyl complexes of the type [NEt4][M2(/a-X)3(CO)4(17 -03115)2] (5), which are prepared by reaction of [NEt4][MX(CO)5] with C3H5X. A year later, Murdoch and Henzi described the bridge-splitting reactions of (5) (M = Mo, X = Cl) with nitrogen donors such as pyridine or bipy to yield complexes of the type 6. 

Similarly many other 17 -allyl carbonyl complexes convert to -allyI complexes with loss... 

Allyl carbonyl complexes can also be prepared by reacting an anionic species with an allyl halide. An -allyl derivative is formed initially. If the formal coordination number of the metal in this intermediate is five it loses carbon monoxide spontaneously to give an rj -a y. Thus Co(CO) and Fe(CO)3(NO)" yield ( -03115)00(00)3 or (y/ -03H5)Fe(00)2(NO) directly. One mole of 00 is easily displaced by phosphines (L) from these products to form derivatives e.g. Co rj -03H5)(00)2L which are much more stable thermally and to oxidation than the parent compounds. When the formal coordination number in the initially formed yy -complex is six or seven, heating or, better, irradiation is usually required to displace carbon monoxide to form the y/ -allyl. Thus M(CO)5 (M = Mn, Re) gives (yy -C3H5)M (00)5 which can be decomposed to rj -C R )M C0) in a subsequent step ... 

Allylation of perfluoroalkyl halides with allylsilanes is catalyzed by iron or ruthenium carbonyl complexes [77S] (equation 119) Alkenyl-, allyl-, and alkynyl-stannanes react with perfluoroalkyl iodides 111 the presence ot a palladium complex to give alkenes and alkynes bearing perfluoroalkyl groups [139] (equation 120)... 

Pseudo-allyl metal carbonyl complexes. T. Inglis, Inorg. Chim. Acta, Rev., 1973, 7, 35-42 (43). 

Alkali Metal Derivatives of Metal Carbonyls, 2, 1S7 Alkyl and Aryl Derivatives of Transition Metals, 7, 1S7 Alkyl cobalt and Acylcobalt Tetracarbonyls, 4, 243 Allyl Metal Complexes, 2, 32S... 

Me3SiPdSnBu3 is formed primarily from 6/1-237, which then adds to the allene moiety in 6/1-236 to give a a- or Jt-allyl palladium complex. This undergoes an intramolecular carbonyl allyl addition to afford the cis-cycloalkariols 6/1-238 (Scheme 6/1.61). 

Allyl methylcarbonate reacts with norbornene following a ruthenium-catalyzed carbonylative cyclization under carbon monoxide pressure to give cyclopentenone derivatives 12 (Scheme 4).32 Catalyst loading, amine and CO pressure have been optimized to give the cyclopentenone compound in 80% yield and a total control of the stereoselectivity (exo 100%). Aromatic or bidentate amines inhibit the reaction certainly by a too strong interaction with ruthenium. A plausible mechanism is proposed. Stereoselective CM-carboruthenation of norbornene with allyl-ruthenium complex 13 followed by carbon monoxide insertion generates an acylruthenium intermediate 15. Intramolecular carboruthenation and /3-hydride elimination of 16 afford the -olefin 17. Isomerization of the double bond under experimental conditions allows formation of the cyclopentenone derivative 12. 

Abstract Aldehydes obtained from olefins under hydroformylation conditions can be converted to more complex reaction products in one-pot reaction sequences. These involve heterofunctionalization of aldehydes to form acetals, aminals, imines and enamines, including reduction products of the latter in an overall hydroaminomethylation. Furthermore, numerous conversions of oxo aldehydes with additional C.C-bond formation are conceivable such as aldol reactions, allylations, carbonyl olefinations, ene reactions and electrophilic aromatic substitutions, including Fischer indole syntheses. 

Syntheses of primary ally lie amines have been reviewed183. The regiochemistry of the reaction of iron carbonyl complexes with nucleophiles such as morpholine has been investigated. The (r 3-crolyl) Fe+(CO)4 BF4- complexes 172 (R1 = H R2 = Me or R1 = Me R2 = H) undergo preferential attack at the less substituted allyl terminus to yield allylic amines 173. The (/j2-crotyl acetate) Fe(CO)4 complex 174, on the other hand, does not react with morpholine184. 

The phase-transfer catalysed reaction of nickel tetracarbonyl with sodium hydroxide under carbon monoxide produces the nickel carbonyl dianions, Ni,(CO) 2- and Ni6(CO)162, which convert allyl chloride into a mixture of but-3-enoic and but-2-enoic acids [18]. However, in view of the high toxicity of the volatile nickel tetracarbonyl, the use of the nickel cyanide as a precursor for the carbonyl complexes is preferred. Pretreatment of the cyanide with carbon monoxide under basic conditions is thought to produce the tricarbonylnickel cyanide anion [19], as the active metal catalyst. Reaction with allyl halides, in a manner analogous to that outlined for the preparation of the arylacetic acids, produces the butenoic acids (Table 8.7). 

Gyclization/hydrosilylation of enynes catalyzed by rhodium carbonyl complexes tolerated a number of functional groups, including acetate esters, benzyl ethers, acetals, tosylamides, and allyl- and benzylamines (Table 3, entries 6-14). The reaction of diallyl-2-propynylamine is noteworthy as this transformation displayed high selectivity for cyclization of the enyne moiety rather than the diene moiety (Table 3, entry 9). Rhodium-catalyzed enyne cyclization/hydrosilylation tolerated substitution at the alkyne carbon (Table 3, entry 5) and, in some cases, at both the allylic and terminal alkenyl carbon atoms (Equation (7)). 

The Pd-catalyzed reaction of 5-vinyl-l,3-oxazolidin-2-ones 260 at 65-70°C and 65 atm of CO in ethanol gave 5-lactams 263 in fairly good to high yields (Scheme 38).As Scheme 38 illustrates, this decarboxylative carbonylation reaction is likely to involve (i) the cleavage of the allylic C-O bond of 260 to form tr-allyl-Pd complex syn-2(A, (ii) isomerization to anti-2(A, (iii) decarboxylation forming 7r-allyl-Pd-amine complex 262, and (iv) CO insertion to 262 followed by aminolysis to yield 5-lactam 263. 

A review of diene-iron carbonyl complexes has recently appeared (5) metal complexes of di- and oligoolefinic ligands have also been reviewed (6). A general review of olefin, acetylenic, and 7r-allylic complexes of transition metals is due to Guy and Shaw (7). 

In other variations ketones are produced. The acyliron monoanion may be alkylated again with another alkyl halide to form a transient acyl-alkyl iron intermediate, which rapidly decomposes into ketone and the polynuclear iron carbonyl complex. This reaction is limited, however, because only very reactive alkylating agents such as methyl, allyl, and benzyl halides will react with the weakly nucleophilic acyliron monoanions ... 

Carbonyl complexes with actinides, 4, 192 (7 5-acyclic)Re(CO)3 complexes, 5, 919 allylation, 10, 663 with allylic tins, 9, 354 into 7 3-allyl palladium complexes, 8, 364 arene chromium carbonyls... 

Cyclopentadienyl carbonyl complexes, with niobium, 5, 64 Cyclopentadienyl chromium bis(Ti-allyl) complexes, with chromium, 5, 305-306 Cyclopentadienyl chromium carbonyls... 

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