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The enantiomeric purity of a chiral compound is determined by NMR spectroscopic analysis of the diastereomers formed with a chiral derivatizing agent. Fluorinated O-aryllactic acids (FAC) 1 are efficient chiral reporters, whose spectacular remote anisotropic effects allow an easy identification and measurement of diastereomers. The remote effects are attributed to the particular design of FAC esters relative to other CDAs.

Many palladium-catalyzed organic reactions with tailored ligands, besides the princess of asymmetric catalysis, allylic alkylation, are suitable for enantioselective organic synthesis. This is clearly illustrated by the large number of promising examples such as the Heck reaction, and Wacker-type oxidations, cycloadditions, cycloisomerizations, carbonylations, and copolymerization of alkenes with carbon monoxide.

Nucleophilic attack of acetate ion on an olefinic bond of dichloro (η 4 -cis-1,2-divinylcyclohexane) palladium has been shown by NMR spectroscopy to lead to a σ,π-palladium (II) complex. This complex, which is also formed from nucleophilic attack on cis-1,2-divinylcyclohexane in the presence of palladium (II) acetate, spontaneously undergoes migratory insertion of the remaining olefinic bond into the palladium-carbon σ bond. This is followed by β-elimination to yield (1R*, 6S*, 7S*)-7-acetoxy-9-methylenebicyclo [4.3.0] nonane together with some rearranged products. The insertion has been shown to be favored by acidic reaction conditions

The Mukaiyama and Palomo reagents have been used for the kinetic resolution of racemic carboxylic acids or alcohols with homochiral alcohols or carboxylic acids, respectively, in the presence of triethylamine. Thus, enantiomerically enriched carboxylic acids (e.e.

Molecular sieves have been shown to improve greatly the stereoselectivity in the palladium(II)-catalyzed reaction of cis-1,2-divinylcyclohene with chiral acids. Reactions run with molecular sieves and derivatives of (R)-lactic acids as nucleophiles always yielded products with S configuration at the newly formed chiral center in contrast to reactions without molecular sieves that gave products with either S or R configuration at this chiral center. It appears that this effect has not been observed previously

The modification of the aromatic part of fluorinated O -aryl lactic acids allows the improvement of the fluorine NMR δΔ values in diastereomeric esters, but also the observation of other nuclei such as Hg ( δΔ > 6 ppm). The enantiomeric purity of chiral acids has been determined through the dl- and meso compounds formed from achiral diols.

Many palladium-catalyzed organic reactions with tailored ligands, besides the princess of asymmetric catalysis, allylic alkylation, are suitable for enantioselective organic synthesis. This is clearly illustrated by the large number of promising examples such as the Heck reaction, and Wacker-type oxidations, cycloadditions, cycloisomerizations, carbonylations, and copolymerization of alkenes with carbon monoxide.

The mechanism of the loss of stereospecificity in palladium-catalyzed nucleophilic substitution of allylic substrates has been investigated. Eight substrates (cis and trans isomers of 1a-d) and two nucleophiles (Et2NH and NaCH(SO2Ph)2) were studied. In the animation reactions two pathways are responsible for the formation of anomalous inversion product, viz., isomerization of the starting material (path B, Scheme 2) and isomerization of the π-allyl intermediate via displacement of palladium by Pd(0) (path C, Scheme 2), the latter of which predominates. In the alkylation the results indicate that loss of stereospecificity is caused only by path C. The use of a more reactive substrate increased the stereospecificity of the reaction and suppressed the isomerization pathway. An analysis of the kinetics is consistent with the hypothesis that path C is the major pathway for the stereochemical loss.

This review deals with the application of Lewis super acids such as Al(III), In(III), and Sn(IV) triflates and triflimidates as catalysts in the synthesis of fragrance materials. Novel catalytic reactions involving C-C and C-heteroatom bond-forming reactions, as well as cycloisomerization processes are presented. In particular, Sn(IV) and Al(III) triflates were employed as catalysts in the selective cyclization of unsaturated alcohols to cyclic ethers, as well as in the cyclization of unsaturated carboxylic acids to lactones. The addition of thiols and thioacids to non-activated olefins, both in intra- and intermolecular versions, was efficiently catalyzed by In(III) derivatives. Sn(IV) Triflimidates catalyzed the cycloisomerization of highly substituted 1,6-dienes to gem-dimethyl-substituted cyclohexanes bearing an isopropylidene substituent. The hydroformylation of these unsaturated substrates, catalyzed by a Rh(I) complex with a bulky phosphite ligand, selectively afforded the corresponding linear aldehydes. The olfactory evaluation of selected heterocycles, carbocycles, and aldehydes synthesized is also discussed.

Bases such as caesium carbonate efficiently catalyze the regioselective ring opening of propylene and styrene oxide with various substituted pyrazoles.

The synthesis and characterization of a new active P*-active phosphapalladacycle and its successful use in the asymmetric hydroarylation of norbornene with turnover numbers (TONs) of up to 1010 is described.

La cyclisation oxydante de dienes-1,5 dans l'acide acetique en presence d'un systeme catalytique se regenerant a base de Pd(II)/Pd(OAc) 2 /MnO 2 /p-benzoquinone conduit, en fonction de la structure du diene-1,5, a des acetoxyexomethylenecyclopentanes ou a des acetoxyvinylcyclopentanes. Cette methode permet d'acceder a des nouveaux systemes cyclopentaniques

Das vollstandige Manuskript dieser Zuschrift erscheint in: Angew. Chem. Suppl. 1982, 922. DOI: 10.1002/ange.198209220

Etude des reactions des chlorures de neopentyl- et cyclohexylmethyl- mercure, catalysees par l'acetate de palladium (II) en presence de CuCl 2 -LiCl-acide acetique

La conversion selective de monoolefines en acetates d'allyle est realisee avec un nouveau systeme catalytique. On transforme ainsi le cyclohexene en acetoxy-3cyclohexene en presence de Pd(OAc) 2 /benzoquinone/MnO 2 -HOAc avec un rendement de 60-90%

Hexa-1,5-dienes undergo oxidative ring closure catalysed by palladium acetate using p-benzoquinone–manganese dioxide as oxidant to give acetoxy-substituted methylene-cyclopentane derivatives.

Aus dem N-Chlor-amin (I) erhalt man mit Aluminiumchlorid oder mit Bortri= fluoridatherat die Umlagerungsprodukte (IIa), (IIIa) und (IV), mit Aluminiumbromid neben (IV) die entsprechenden Bromide (IIb) und (IIIb).

La conversion selective de monoolefines en acetates d'allyle est realisee avec un nouveau systeme catalytique. On transforme ainsi le cyclohexene en acetoxy-3cyclohexene en presence de Pd(OAc) 2 /benzoquinone/MnO 2 -HOAc avec un rendement de 60-90%