Mechanistic and synthetic studies in catalytic allylic alkylation with palladium complexes of 1-(2-diphenylphosphino-1-naphthyl)isoquinoline

Brown, John M.; Hulmes, David I.; Guiry, Patrick J.

doi:10.1016/s0040-4020(01)89381-9

Cited by 282 publications

(129 citation statements)

References 42 publications

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“…These include chiral PÀN ligands, as was demonstrated by Pfaltz and Helmchen, who employed chiral phosphinooxazoline ligands possessing C 1 symmetry. [5,[11][12][13][14][15][16][17][18] The difference in donor properties of the coordinating phosphorus and nitrogen atoms offered the possibili-Abstract: A series of bulky monodentate phosphoramidite ligands, based on biphenol, BINOL and TADDOL backbones, have been employed in the Pdcatalysed 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.…”

Section: Introductionmentioning

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

111

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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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Section: Introductionmentioning

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

111

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“…Firstly, we tested the Pd-catalyzed allylic substitution reaction [11] ( Table 1). Treatment of (E)-1,3-diphenylallyl acetate (10) with dimethyl malonate (11) in the presence of (S P )-4 or (R P )-5 and [Pd(allyl)Cl] 2 as catalyst precursor gave the allylated malonate 13 [12] (20% ee with 4 and 31% ee with 5). The same procedure with benzylamine (12) as nucleophile gave the allylamine derivative 14 [13] in 86% yield, but with only 15% ee.…”

Section: Resultsmentioning

confidence: 99%

New Monodentate P,C‐Stereogenic Bicyclic Phosphanes: 1‐Phenyl‐1,3a,4,5,6,6a‐hexahydrocyclopenta[b]phosphole and 1‐Phenyloctahydrocyclopenta[b]phosphole

et al. 2004

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Racemic 1-phenyl-1,3a,4,5,6,6a-hexahydrocyclopenta[b]-phosphole (4) was separated into enantiomerically pure 1-phenyl-1,3a,4,5,6,6a-hexahydrocyclopenta[b]phosphole 1-oxides [(R P )-6 and (S P )-6] by an oxidative resolution procedure involving treatment of 4 with menthyl bromoacetate, crystallization of the resulting diastereoisomeric phosphonium bromides 8, and stereoselective hydrolysis of the diastereomerically pure salts to the corresponding enantiomerically pure phosphane oxides. Stereoretentive reduction of P=O in

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“…It is to be noted that these enantioselectivities are quite close to those observed when the reaction was performed in THF. [32] Quinap or Trost×s ligand gave moderate enantioselectivities (65% and 52% ee, respectively), and conversions (Table 6, entries 8 and 10), lower than those obtained in an organic solvent [32] . Josiphos gave also moderate enantioselectivity (66% ee), but with very low conversion (10%) ( Table 6, entry 11).…”

Section: Full Papersmentioning

confidence: 88%

Catalytic Asymmetric Alkylation in Water in the Presence of Surfactants

2003

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Asymmetric palladium-catalyzed alkylation of 1,3-diphenyl-2-propenyl acetate with dimethyl malonate occurs in water in the presence of surfactants and a base. The efficiency as well as the enantioselectivity of the coupling reaction depend strongly on the nature and the concentration of the surfactant. The highest yield and enantioselectivity (up to 91%) was obtained using Binap as the ligand in the presence of a cationic surfactant, while neutral or zwitterionic surfactants gave poorer results; anionic surfactants gave no reaction at all. The best results were obtained using Na 2 CO 3 , NaHCO 3 , or K 2 CO 3 , among the bases used. The highest enantioselectivities were obtained when the reaction was performed in the presence of chiral atropoisomeric diphosphines such as Binap, Biphemp, or MeOBiphep. A supported cationic surfactant was also used successfully in this reaction, allowing an easier separation of the product.

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Mechanistic and synthetic studies in catalytic allylic alkylation with palladium complexes of 1-(2-diphenylphosphino-1-naphthyl)isoquinoline

Cited by 282 publications

References 42 publications

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

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

New Monodentate P,C‐Stereogenic Bicyclic Phosphanes: 1‐Phenyl‐1,3a,4,5,6,6a‐hexahydrocyclopenta[b]phosphole and 1‐Phenyloctahydrocyclopenta[b]phosphole

Catalytic Asymmetric Alkylation in Water in the Presence of Surfactants

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