Easily accessible chiral amino-phosphinite ligands for highly enantioselective palladium-mediated allylic alkylation

Chen, Guoshu; Li, Xin; Zhang, Hai-Le; Gong, Liu‐Zhu; Mi, Aiqiao; Cui, Xin; Jiang, Yaozhong; Choi, Michael C. K.; Chan, Albert S. C.

doi:10.1016/s0957-4166(02)00204-5

Cited by 31 publications

(11 citation statements)

References 28 publications

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“…E-mail: ania@wchuwr.chem.uni.wroc.pl ligands derived from D-glucosamine worked efficiently in asymmetric allylic substitution. 5 Good results, represented by high ee values, have also been obtained in this reaction with a palladium catalyst containing furanoside thioether-phosphinite, 6 aminophosphonites, 7 as well as N,P-donor oxazoline phosphinites. 8, 9 Surprisingly, in spite of their generally higher air-stability compared to phosphines, phosphinites have seldom been used in palladium-catalyzed C-C bond forming reactions, such as methoxycarbonylation of aryl halides or Heck or Suzuki coupling.…”

Section: Introductionmentioning

confidence: 67%

Chemistry of palladium phosphinite (PPh₂(OR)) and phosphonite (P(OPh)₂(OH)) complexes: catalytic activity in methoxycarbonylation and Heck coupling reactions

et al. 2006

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The new phosphinite and phosphonite complexes (1-8) are very efficient catalysts for the methoxycarbonylation of iodobenzene and Heck cross-coupling of bromobenzene with butyl acrylate. High catalytic activity of these complexes can be explained by their in situ transformations during the reaction, stimulated by the presence of water, acid (HCl) or base (NEt(3)). Hydrolysis of phosphinite palladium complexes of the form trans-PdCl(2)[PPh(2)(OR)](2) (R = C(6)F(5), 2, (t)Bu 3, or O-menthyl 4) results in the formation of the dimeric complex [mu-ClPd(PPh(2)OH)(PPh(2)O)](2) 5, which is deprotonated by NEt(3), producing a polymeric complex of formula [Pd(P(O)PPh(2))(2)](n) 8. The reverse reaction, protonolysis of 8 with HCl, leads back to 5 and the monomeric complex 5a. The phosphinite complex PdCl(2)[PPh(2)(OBu)](2)1 with a more lipophilic ligand, PPh(2)(OBu), does not undergo hydrolysis under the same conditions. In the reaction of PdCl(2)(cod) with P(OPh)(2)(OH), the new dimer [mu-ClPd(P(OPh)(2)OH)(P(OPh)(2)O)](2) 6 was obtained, whereas reaction of Pd(OAc)(2) with P(OPh)(2)(OH) leads to the polymeric complex [Pd[P(O)(OPh)(2)](2)](n) 7. Protonolysis of 7 with HCl results in the formation of 6.

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Section: Introductionmentioning

confidence: 67%

Chemistry of palladium phosphinite (PPh₂(OR)) and phosphonite (P(OPh)₂(OH)) complexes: catalytic activity in methoxycarbonylation and Heck coupling reactions

et al. 2006

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“…Ideally, these labile oxygen‐sensitive intermediates should be converted fast, without further purification, to the corresponding oxygen‐stable iridium complexes. Therefore, we examined an alternative method for this critical step that was based on a procedure reported by Knochel and co‐workers for the formation of P−O‐bonds [52–55] . They observed rapid phosphinite formation within 30 minutes at room temperature by using equimolar amounts of an alcohol, chlorodiphenylphosphine and 4‐( N , N ‐dimethylamino)pyridine in diethyl ether.…”

Section: Resultsmentioning

confidence: 99%

“…We thank Dr. Sigmund Gunzenhauser for his help with difficult chromatographic separations. We also thank one of the reviewers for bringing references [39][40][41] and [53][54][55] to our attention.…”

Section: Acknowledgementsmentioning

confidence: 99%

Optimized Scalable Synthesis of Chiral Iridium Pyridyl‐Phosphinite (Pyridophos) Catalysts

Müller

Ganić

Hörmann

et al. 2020

Helvetica Chimica Acta

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Dedicated to Prof. Antonio Togni on the occasion of his 65th birthday Iridium catalysts with chiral P,N ligands have greatly enhanced the scope of asymmetric olefin hydrogenation because they do not require a coordinating group near the C=C bond like Rh and Ru catalysts. Pyridophos ligands, possessing a conformationally restricted annulated pyridine framework linked to a phosphinite group, proved to be particularly effective, inducing high enantioselectivities in the hydrogenation of a remarkably broad range of substrates. Here we report the development of an efficient scalable synthesis for the two most versatile Ir-pyridophos catalysts, derived from 2-phenyl-8-hydroxy-5,6,7,8-tetrahydroquinoline or the analogue with a fivemembered carbocyclic ring, respectively, by modification and optimization of the original synthetic route. The optimized route renders both catalysts readily accessible in multi-gram quantities in analytically pure form in overall yields of 26-37 %, starting from acetophenone and cyclopentanone or cyclohexanone, respectively. A major advantage of the new synthesis is the efficient and practical kinetic resolution of the late-stage pyridyl alcohol intermediates with commercial immobilized Candida antarctica lipase B, giving access to both enantiomers of these catalysts as essentially enantiopure compounds. The catalysts are obtained as crystalline solids, which are air-stable and can be stored for years at À 20°C without notable decomposition.

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“…[5] Chan et al have also employed amino alcohols as starting materials for their synthesis of the phosphinite ligands 168 ± 175, in this case using (1R,2S) and (1S,2S)-1,2-diphenyl-2-aminoethanol. [58] In the allylic alkylation of the standard diphenyl-substituted allyl substrate 15 the enantioselectivity decreased on going from 168 to 169 and the configuration was inverted with 170 and 171, Table 13, entries 1 ± 4. The use of ligands 173 ± 175 gave a dramatic improvement whereby enantiomeric excesses of up to 95% were obtained.…”

Section: Azepine N Donormentioning

confidence: 99%

The Development of Bidentate P,N Ligands for Asymmetric Catalysis

2004

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In this review, an attempt is made to systemise the ro √ le which bidentate phosphinamine (P,N) ligands play in asymmetric catalysis. The ligands will be classified, not by the reaction to which their metal complexes have been applied, but by the nature of their donor atoms. In this manner the development of ligand architectural design can be more easily monitored. The asymmetric transformations to which metal complexes of these ligands have been applied include among others, palladium-catalysed allylic substitutions, copper-catalysed 1,4-additions to enones and rhodiumcatalysed hydroboration of vinylarenes. Excellent enantioselectivities, regioselectivities and reactivities have been achieved in each of these processes.

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Easily accessible chiral amino-phosphinite ligands for highly enantioselective palladium-mediated allylic alkylation

Cited by 31 publications

References 28 publications

Chemistry of palladium phosphinite (PPh₂(OR)) and phosphonite (P(OPh)₂(OH)) complexes: catalytic activity in methoxycarbonylation and Heck coupling reactions

Chemistry of palladium phosphinite (PPh₂(OR)) and phosphonite (P(OPh)₂(OH)) complexes: catalytic activity in methoxycarbonylation and Heck coupling reactions

Optimized Scalable Synthesis of Chiral Iridium Pyridyl‐Phosphinite (Pyridophos) Catalysts

The Development of Bidentate P,N Ligands for Asymmetric Catalysis

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Easily accessible chiral amino-phosphinite ligands for highly enantioselective palladium-mediated allylic alkylation

Cited by 31 publications

References 28 publications

Chemistry of palladium phosphinite (PPh2(OR)) and phosphonite (P(OPh)2(OH)) complexes: catalytic activity in methoxycarbonylation and Heck coupling reactions

Chemistry of palladium phosphinite (PPh2(OR)) and phosphonite (P(OPh)2(OH)) complexes: catalytic activity in methoxycarbonylation and Heck coupling reactions

Optimized Scalable Synthesis of Chiral Iridium Pyridyl‐Phosphinite (Pyridophos) Catalysts

The Development of Bidentate P,N Ligands for Asymmetric Catalysis

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Chemistry of palladium phosphinite (PPh₂(OR)) and phosphonite (P(OPh)₂(OH)) complexes: catalytic activity in methoxycarbonylation and Heck coupling reactions

Chemistry of palladium phosphinite (PPh₂(OR)) and phosphonite (P(OPh)₂(OH)) complexes: catalytic activity in methoxycarbonylation and Heck coupling reactions