Highly Enantioselective Nickel-Catalyzed Hydrovinylation with Chiral Phosphoramidite Ligands

Franciò, Giancarlo; Faraone, Felice; Leitner, Walter

doi:10.1021/ja012099v

Cited by 135 publications

(65 citation statements)

References 15 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Next, effect of different solvents on the selectivities was examined. The reactions in toluene, tetrahydrofuran, CH 2 Cl 2 , and MeOH also gave 8 in complete conversion under the same reaction conditions and no hydrogenation product was observed (entries [11][12][13][14]. However, the reactions in tetrahydrofuran and CH 2 Cl 2 gave 8 with lower branched-to-linear ratio and enantiopurity (entries 12 and 13), and the reaction in MeOH gave lower enantioselectivity (entry 14) than those in benzene and toluene.…”

Section: Resultsmentioning

confidence: 86%

“…1). These ligands have found a wide range of applications in metalcatalyzed asymmetric transformations such as hydrogenation (5,(8)(9)(10)), 1,4-additions of dialkylzinc (11,12) and boronic acids (13) to enones, hydrovinylation (14), hydrosilylation (15), intramolecular Heck reaction (16), hydroformylation (17), allylic alkylation (18,19), amination (20), and etherification (21).…”

mentioning

confidence: 99%

See 1 more Smart Citation

New biphenol-based, fine-tunable monodentate phosphoramidite ligands for catalytic asymmetric transformations

Hua

Vassar

Choi

et al. 2004

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

Monodentate phosphoramidite ligands have been developed based on enantiopure 6,6-dimethylbiphenols with axial chirality. These chiral ligands are easy to prepare and flexible for modifications. The fine-tuning capability of these ligands plays a significant role in achieving high enantioselectivity in the asymmetric hydroformylation of allyl cyanide and the conjugate addition of diethylzinc to cycloalkenones. R ecently, chiral monodentate phosphorus ligands (phosphites, phosphoramidites, and phosphonites) have been attracting considerable interest for their use in catalytic asymmetric synthesis, because the chiral catalysts bearing these ligands have proven to be highly efficient in various asymmetric reactions. This is a previously univestigated wave in the design of chiral ligands, which makes a sharp contrast to almost three decades of predominance by C2 symmetrical bidentate phosphorus ligands for a variety of catalytic asymmetric transformations. This wave of designing simple and readily modifiable chiral structures, which are easy to synthesize, is fitting very well to the trendy and highly practical combinatorial approaches to the development of the most suitable chiral ligand for a particular catalytic asymmetric process of commercial value or academic interest. This approach is currently considered most practical rather than trying to develop a universal and almighty chiral ligand for different types of catalytic asymmetric transformations.Before the launch of our research program on the development of chiral monodentate phosphorus ligands based on enantiopure 2,2Ј-dihydroxy-6,6Ј-dimethylbiphenyls, by far, the most studied monodentate ligands were phosphites and phosphoramidites based on TADDOL (1) (1) BINOL (2) (2-4), a spirobiindanediol (3) (5), or an achiral biphenol (4) (6, 7) bearing a chiral or achiral secondary alcohol or amine (Fig. 1). These ligands have found a wide range of applications in metalcatalyzed asymmetric transformations such as hydrogenation (5, 8-10), 1,4-additions of dialkylzinc (11, 12) and boronic acids (13) to enones, hydrovinylation (14), hydrosilylation (15), intramolecular Heck reaction (16), hydroformylation (17), allylic alkylation (18, 19), amination (20), and etherification (21).We have been developing a previously uninvestigated class of chiral monodentate phosphite and phosphoramidite ligands, 5 and 6, from readily accessible enantiopure, axially chiral biphenyls ( Fig. 2) and have recently published the successful application of chiral monophosphite ligands 5 to the Rh(I)-catalyzed asymmetric hydrogenation of dimethyl itaconate (Fig. 2) (22).One of the salient and practical features of these chiral monophosphite ligands is the fine-tuning capability with modifiable substituents R 1 , R 2 , and R 3 in the formula 5. This fine-tuning capability of ligands 5 (phosphites) and 6 (phosphoramidites) is expected to play a crucial role in the application of these ligands to a variety of catalytic asymmetric reactions. In fact, we have demonstrated that the substituents (R 2 )...

show abstract

Section: Resultsmentioning

confidence: 86%

mentioning

confidence: 99%

New biphenol-based, fine-tunable monodentate phosphoramidite ligands for catalytic asymmetric transformations

Hua

Vassar

Choi

et al. 2004

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

show abstract

“…Phosphoramidites have been successfully employed in the copper-catalysed asymmetric diethylzinc addition to enones, [16] iridium-catalysed substitution of allylic acetates, [17] copper-catalysed allylic alkylations, [18] rhodium-catalysed asymmetric olefin hydrogenations, [19] palladium-catalysed asymmetric Heck reactions, [20] rhodium-catalysed asymmetric arylation of enones, [21] nickel-catalysed asymmetric hydrovinylations, [22] and palladium-catalysed asymmetric hydrosilylation of olefins. [23] The use of MonoPhos TM (7a) in the hydroformylation of allyl cyanide gave good results with respect to chemo-and regioselectivity.…”

Section: Resultsmentioning

confidence: 99%

Rhodium‐Catalysed Asymmetric Hydroformylation of Unsaturated Nitriles

Lambers‐Verstappen

Vries

2003

Adv Synth Catal

View full text Add to dashboard Cite

Asymmetric hydroformylation of crotononitrile (1) and ally cyanide (2) was probed with the view to develop a synthesis for (R)-4-amino-2-methyl-butan-1-ol. Hydroformylation of 1 under a variety of conditions mainly led to hydrogenated product. Hydroformylation of 2 with Rh/tris(2,4-ditert-butylphenyl) phosphite gave good selectivity to the formylated nitrile with an n/iso of 77:23. Asymmetric hydroformylation of 2 could be accomplished in 66% ee using Rh/(R,S)-BINAPHOS.

show abstract

“…[38] More recently, it has been shown that monodentate phosphoramidites can function as effective chiral ligands in other metal-catalysed reactions such as hydrogenations, [39,40] hydrosilylations [41] and hydrovinylations. [42] Despite the recent increase in interest for phosphoramidites as auxiliaries in catalysis, very few applications in palladium-catalysed allylic subtitution have been reported yet. [43] Several groups have exemplified the potential of chiral phosphoramidites in copper-catalysed allylic alkylations, which proceed through a mechanism (predominantly S N 2' from s-allyl complexes) different from that of the palladium-catalysed reaction.…”

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

109

View full text Add to dashboard Cite

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.

show abstract

Highly Enantioselective Nickel-Catalyzed Hydrovinylation with Chiral Phosphoramidite Ligands

Cited by 135 publications

References 15 publications

New biphenol-based, fine-tunable monodentate phosphoramidite ligands for catalytic asymmetric transformations

New biphenol-based, fine-tunable monodentate phosphoramidite ligands for catalytic asymmetric transformations

Rhodium‐Catalysed Asymmetric Hydroformylation of Unsaturated Nitriles

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

Contact Info

Product

Resources

About