Oxidative addition trans product

In a manner analogous to classic nitrile iinines, the additions of trifluoro-methylacetonitrile phenylimine occur regiospecifically with activated terminal alkenes but less selectively with alkynes [39], The nitnle imine reacts with both dimethyl fumarate and dimethyl maleate m moderate yields to give exclusively the trans product, presumably via epimenzation of the labile H at position 4 [40] (equation 42) The nitrile imine exhibits exo selectivities in its reactions with norbornene and norbornadiene, which are similar to those seen for the nitrile oxide [37], and even greater reactivity with enolates than that of the nitnle oxide [38, 41], Reactions of trifluoroacetomtrile phenyl imine with isocyanates, isothiocyanates, and carbodiimides are also reported [42]... 

In the direct coupling reaction (Scheme 30), it is presumed that a coordinatively unsaturated 14-electron palladium(o) complex such as bis(triphenylphosphine)palladium(o) serves as the catalytically active species. An oxidative addition of the organic electrophile, RX, to the palladium catalyst generates a 16-electron palladium(n) complex A, which then participates in a transmetalation with the organotin reagent (see A—>B). After facile trans- cis isomerization (see B— C), a reductive elimination releases the primary organic product D and regenerates the catalytically active palladium ) complex. 

The dominant factors reversing the conventional ds-hydroboration to the trans-hydroboration are the use of alkyne in excess of catecholborane or pinacolborane and the presence of more than 1 equiv. of EtsN. The P-hydrogen in the ris-product unexpectedly does not derive from the borane reagents because a deuterium label at the terminal carbon selectively migrates to the P-carbon (Scheme 1-5). A vinylidene complex (17) [45] generated by the oxidative addition of the terminal C-H bond to the catalyst is proposed as a key intermediate of the formal trans-hydroboration. 

The detailed decomposition (P-H ehminahon) mechanism of the hydrido(alkoxo) complexes, mer-crs-[lr(H)(OR)Cl(PR 3)3] (R = Me, Et, Pr R = Me, Et H trans to Cl) (56, 58, 60), forming the dihydrides mer-cis-[lr H)2Cl PR )2] (57, 59) along with the corresponding aldehyde or ketone was examined (Scheme 6-8). The hydrido(ethoxo) as well as the hydrido(isopropoxo) complexes 60 could also be prepared by oxidative addition of ethanol and isopropanol to the phosphine complexes 39 [44]. In the initial stage of the P-H elimination, a pre-equiUbrium is assumed in which an unsaturated pentacoordinated product is generated by an alcohol-assisted dissociation of the chloride. From this intermediate the transition state is reached, and the rate-determining step is an irreversible scission of the P-C-H bond. This process has a low... 

Examples of the isolation of hydrido(carboxylato) complexes by oxidative addition of carboxylic acid are very rare. Wilkinson [55] examined oxidative addition of fluoro carboxylic acids to Vaska s complex, trans-[lrCl(CO)(PPh3)2]. They isolated colorless hydrido(carboxylato) complexes of stoichiometry, [lrCl(H)(OCORF)(CO)(PPh3)2] (RE = CE3, C2F5), but did not completely succeed in characterizing the products of the oxidative addition. The complex is claimed to be a mixture of four closely similar... 

The mechanism for the reaction catalyzed by cationic palladium complexes (Scheme 24) differs from that proposed for early transition metal complexes, as well as from that suggested for the reaction shown in Eq. 17. For this catalyst system, the alkene substrate inserts into a Pd - Si bond a rather than a Pd-H bond [63]. Hydrosilylation of methylpalladium complex 100 then provides methane and palladium silyl species 112 (Scheme 24). Complex 112 coordinates to and inserts into the least substituted olefin regioselectively and irreversibly to provide 113 after coordination of the second alkene. Insertion into the second alkene through a boat-like transition state leads to trans cyclopentane 114, and o-bond metathesis (or oxidative addition/reductive elimination) leads to the observed trans stereochemistry of product 101a with regeneration of 112 [69]. 

Trans oxidative addition of CH3I to [Ir(acac)(cod)] affords the structurally determined complex [Ir(acac)(cod)(CH3)1].241 The reaction of [(Npet)2Ir]Cl, Npet = o-(diphenylphosphino)benzylide-nejethylamino, with tetrachloro-o-quinone yields the structurally characterized product (135).242 The synthesis and characterization of the water-soluble complex (136) have been described.243... 

Organoiron complexes (7) are converted in high yield into ammonium salts (8) these in turn undergo oxidatively induced ligand transfer and cyclization to give azetidinones (9) in moderate yields (Scheme 9). Formation of the trans product (9b) indicates a stereochemical sequence of trans addition to the olefin complex followed by carboxamidation with retention of configuration at the C—Fe bond. 

Perhalogenoaryls are more stable than the unsubstituted phenyls [176] and can be synthesized conveniently by oxidation of gold(I) complexes (demonstrating the stability of the Au-C bond). The initial product of oxidation addition seems to be the trans-isomer, which generally rearranges to the m-form ... 

In the oxidative addition of a fluorinated aryl iodide, 43, to Pd(PPh3)2 (Figure 1.12) [29], F NMR has been used to follow the ds-to-trans isomerization of the ds-bis-phosphine product, 44, to the trans-isomer, 45. The F NMR kinetic study reveals a first order dependence for the rate of isomerization on the concentration of 44. An application of a F NMR kinetic study to the evaluation of the... 

The overall reaction is best viewed as intramolecular oxidative addition of the C(l)—H bond to the Rh(I) center, causing cyclometalation (25), followed by reductive elimination of an enamine from the Rh(III) intermediate accompanied by allylic transposition. Notably, the allylamine ligand in the initial Rh(I) complex as well as the Rh(III) intermediate has an s-trans conformation with respect to the N—C(l) and C(2)—C(3) bonds, allowing the overall suprafacial 1,3-hydrogen shift to produce the is-configured enamine product. 

The biotransformation of linalool by Botrytis cinerea has also been described [60]. After addition of linalool to botrytised must, a series of transformation products was identified (E)- (49) and (Z)-2,6-dimethyl-2,7-octadiene-l,6-diol (48), trans- (76) and cw-furanoid linalool oxide (77), trans- (78) and c/s-pyranoid linalool oxide (79) and their acetates (80, 81), 3,9-epoxy-p-menth-1 -ene (75) and 2-methyl-2-vinyltetrahydrofuran-5-one (66) (unsaturated lactone), Fig. (11). Quantitative analysis however, showed that linalool was predominantly (> 90%) metabolised to ( )-2,6-dimethyl-2,7-octadiene-l,6-diol (49) by B. cinerea. The other compounds were only found as by-products in minor concentrations. 

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