Asymmetric synthesis. Asymmetric catalytic allylation using palladium chiral phosphine complexes

Auburn, Pamela R.; Mackenzie, P. B.; Bosnich, B.

doi:10.1021/ja00293a038

Cited by 437 publications

(214 citation statements)

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“…A cold solution of freshly prepared sodium hypobromite (15 μl) (Auburn et al, 1985) was added to a stirred solution of this sample in 1,4-dioxane (15 μl) and water (7.5 μl) in a 1-ml Reacti-Vial at 0°C. The mixture was stirred at 0°C for 3 hr and then quenched by addition of a drop of aqueous sodium bisulfite (10%).…”

Section: Resultsmentioning

confidence: 99%

Chemical Characterization of Territorial Marking Fluid of Male Bengal Tiger, Panthera tigris

Burger

Viviers

Bekker³

et al. 2008

J Chem Ecol

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The territorial marking fluid of the male Bengal tiger, Panthera tigris, consists of a mixture of urine and a small quantity of lipid material that may act as a controlled-release carrier for the volatile constituents of the fluid. Using gas chromatography and gas chromatography-mass spectrometry, 98 volatile compounds and elemental sulfur were identified in the marking fluid. Another 16 volatiles were tentatively identified. The majority of these compounds were alkanols, alkanals, 2-alkanones, branched and unbranched alkanoic acids, dimethyl esters of dicarboxylic acids, γ-and δ-lactones, and compounds containing nitrogen or sulfur. Several samples of the marking fluid contained pure (R)-3-methyl-2-octanone, (R)-3-methyl-2-nonanone, and (R)-3-methyl-2-decanone, but these ketones were partly or completely racemized in other samples. The γ-lactone (S)-(+)-(Z)-6-dodecen-4-olide and the C8 to C16 saturated (R)-γ-lactones and (S)-δ-lactones were present in high enantiomeric purities.The chiral carboxylic acids, 2-methylnonanoic acid, 2-methyldecanoic acid, 2-methylundecanoic acid, and 2-ethylhexanoic acid were racemates. Cadaverine, putrescine, and 2-acetylpyrroline, previously reported as constituents of tiger urine, were not detected. The dominant contribution of some ketones, fatty acids, and lactones to the composition of the headspace of the marking fluid suggests that these compounds may be important constituents of the pheromone. Although it constitutes only a small proportion, the lipid fraction of the fluid contained larger quantities of the volatile organic compounds than the aqueous fraction (urine). The lipid derives its role as controlled-release carrier of the chemical message left by the tiger, from its affinity for the volatiles of the marking fluid. Six proteins with masses ranging from 16 to 69 kDa, inter alia, the carboxylesteraselike urinary protein known as cauxin, previously identified in the urine of the domestic cat and other felid species, were identified in the urine fraction of the marking fluid.

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Section: Resultsmentioning

confidence: 99%

Chemical Characterization of Territorial Marking Fluid of Male Bengal Tiger, Panthera tigris

Burger

Viviers

Bekker³

et al. 2008

J Chem Ecol

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“…Other allylic substrates were prepared following standard procedures. [65] The TADDOL-type backbones employed were synthesised according to literature procedures. [66,67] (R)-3,3'-Trimethylsilyl-1,1'-binaphtyl-2,2'-diol was synthesised as reported by Buisman et al [68] N-Benzyl-(1R,2S)-norephedrine was synthesised by a literature procedure.…”

Section: Methodsmentioning

confidence: 99%

Bulky Monodentate Phosphoramidites in Palladium‐Catalyzed Allylic Alkylation Reactions: Aspects of Regioselectivity and Enantioselectivity

Boele

Kamer

Lutz³

et al. 2004

Chemistry A European J

110

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A series of bulky monodentate phosphoramidite ligands, based on biphenol, BINOL and TADDOL backbones, have been employed in the Pd‐catalysed allylic alkylation reaction. Reaction of disodium diethyl 2‐methyl malonate with monosubstituted allylic substrates in the presence of palladium complexes of the phosphoramidite ligands proceeds smoothly at room temperature. The regioselectivities observed depend strongly on the leaving group and the geometry of the allylic starting compounds. Mono‐coordination occurs when these ligands are ligated in [Pd(allyl)(X)] complexes (allyl=C3H5, 1‐CH3C3H4, 1‐C6H5C3H4, 1,3‐(C6H5)2C3H3; X=Cl, OAc). The solid‐state structure determined by X‐ray diffraction of [Pd(C3H5)(1)(Cl)] reveals a non‐symmetric coordination of the allyl moiety, caused by the stronger trans influence of the phosphoramidite ligand relative to X−. In all of these complexes, the syn,trans isomer is the major species present in solution. Because of fast isomerisation and high reactivity of the syn,cis complex, the major product formed upon alkylation is the linear product, especially for monosubstituted phenylallyl substrates in the presence of halide counterions. In the case of biphenol‐ and BINOL‐based phosphoramidites, however, a strong memory effect is observed when 1‐phenyl‐2‐propenyl acetate is employed as the substrate. In this case, nucleophilic attack competes effectively with the isomerisation of the transient cinnamylpalladium complexes. The asymmetric allylic alkylation of 1,3‐diphenyl‐2‐propenyl acetate afforded the chiral product in up to 93 % ee. Substrates with smaller substituents gave lower enantioselectivities. The observed stereoselectivity is explained in terms of a preferential rotation mechanism, in which the product is formed by attack on one of the isomers of the intermediate [Pd{1,3‐(C6H5)2C3H3}(L)(OAc)] complex.

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“…1,3-Diphenyl-2-propenyl acetate 7a was prepared according to the reported method. 20 1,3-Diphenyl-2-propenyl pivalate 7b was derived from the reaction of 1,3-diphenylprop-2-en-1-ol with pivaloyl chloride in pyridine. 4a, 15b 4b 21 and 4c …”

Section: General Methodsmentioning

confidence: 99%

Ferrocenylphosphine–imine ligands for Pd-catalyzed asymmetric allylic alkylation

Dai

et al. 2002

Tetrahedron: Asymmetry

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Asymmetric synthesis. Asymmetric catalytic allylation using palladium chiral phosphine complexes

Cited by 437 publications

References 0 publications

Chemical Characterization of Territorial Marking Fluid of Male Bengal Tiger, Panthera tigris

Chemical Characterization of Territorial Marking Fluid of Male Bengal Tiger, Panthera tigris

Bulky Monodentate Phosphoramidites in Palladium‐Catalyzed Allylic Alkylation Reactions: Aspects of Regioselectivity and Enantioselectivity

Ferrocenylphosphine–imine ligands for Pd-catalyzed asymmetric allylic alkylation

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