Modular Synthesis of Novel Chiral Phosphorous Triamides Based on (<i>S</i>)‐<i>N</i>‐(Pyrrolidin‐2‐ylmethyl)aniline and Their Application in Asymmetric Catalysis

Barta, Katalin; Hölscher, Markus; Franciò, Giancarlo; Leitner, Walter

doi:10.1002/ejoc.200900477

Cited by 54 publications

(18 citation statements)

References 43 publications

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“…1). 23,33,39- 44 The 31 P NMR spectrum of ligand 2 in CDCl 3 also exhibits two narrow singlets of equal intensities at δ P 112.4 and 112.1. The presence of two signals in the 31 P NMR spectra of diamidophosphites 1 and 2 is due to the non equivalence of their phosphorus centers.…”

Section: Resultsmentioning

confidence: 94%

Palladium-catalyzed allylic substitution assisted by 1,3,2-diazaphospholidine derivatives of (R,R)-N-naphthyltartarimide

et al. 2010

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P,P Bidentate diamidophosphite ligands containing the (3R,4R) 3,4 dioxy 1 (1 naphthyl)pyrrolidine 2,5 dione framework and 1,3,2 diazaphospholidine rings with the ste reogenic P atoms were obtained. The use of these ligands provides up to 85% ee in Pd catalyzed asymmetric amination of (E) 1,3 diphenylallyl acetate and up to 95% ee in its asymmetric alkylation with dimethyl malonate.The preparation of drugs, chemical agents for plant protection, food additives, flavors, and stereoindividual polymers is based on modern approaches to the synthesis of optically pure compounds. One of the leading approach es is asymmetric metal complex catalysis. 1-5 In turn, the activity and stereoselectivity of metal complex catalysts largely depend on the successful strategy of design and synthesis of appropriate chiral ligands, among which phos phorus containing compounds are worth noting. 6,7 Along with classic P,P bidentate phosphines, P,P bidentate phosphite ligands are successfully used because they can simply be prepared from accessible precursors, are inert to oxidants, exhibit pronounced π acidity, and are less ex pensive. 8-14 The main attention of researchers is focused on P,P bidentate phosphites containing 1,3,2 dioxaphos phepine rings based on BINOL, H 8 BINOL, and various 2,2´ dihydroxy 1,1´ biphenyls. 13-22Our investigations deal with the synthesis of various diamidophosphites containing stereogenic P atoms and 1,3,2 diazaphospholidine rings and their use in asymmetric catalytic reactions. 23-28 It should be noted that 1,3,2 di azaphospholidines, including P* chiral ones, are an at tractive group of optically active diamidophosphite ligands. For instance, they have balanced electron characteristics: they are both good π acceptors (because of the accessibil ity of the low energy π* PN orbitals) and good σ donors. Inclusion of a phosphorus atom into the five membered ring makes the ligand more resistant to oxidation and hydrolysis; by widely varying the substituents at the N atoms, one can control its steric and electronic parame ters. 29,30 If the electron donating P atom is asymmetric, this substantially promotes chirality transfer in the key step of the catalytic cycle. 2 In the present work, we report on the synthesis of P,P bidentate diamidophosphites 1 and 2 and their use for enantioselective catalysis (Scheme 1). The 1,3,2 di azaphospholidine rings in these ligands are linked to the sterically rigid tartarimide (3,4 dioxypyrrolidine 2,5 dione) ring. Note that known ligands with the pyrrolidine 2,5 dione fragment L A-C are efficient stereoselectors in Pd catalyzed allylic substitution and Rh catalyzed hydro genation. 31- 33 We tested compounds 1 and 2 in Pd catalyzed asym metric allylation, which is an effective tool for (1) estima tion of the efficiency of novel chiral ligands and (2) stereo selective synthesis of valuable natural compounds. 14,34- 37 We also compared the asymmetry inducing activity of both ligands 1 and 2 themselves and their known analogs L B and L C . Results and DiscussionNovel P,P bidentate ...

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Section: Resultsmentioning

confidence: 94%

Palladium-catalyzed allylic substitution assisted by 1,3,2-diazaphospholidine derivatives of (R,R)-N-naphthyltartarimide

et al. 2010

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“…Note that phosphorylating reagent 5 is readily available 42 in good yield from (S) glut amic acid anilide. 43, 44 Ligand 1 is enantiomerically pure. The presence of the sharp singlet signal at  P 125.7 in the 31 P NMR spectrum (CDCl 3 ) of ligand 1 indicates the (R) configuration of the P* chiral centers.…”

Section: Resultsmentioning

confidence: 99%

“…1). [42][43][44][45][46][47] Diamidophosphite 1 can be easily purified by flash column chromatography; it is relatively stable in air and can be stored for a long time under dry conditions. Tak ing into account the availability of the starting com pounds, ligand 1 can be synthesized in gram scale amounts.…”

Section: Resultsmentioning

confidence: 99%

Phosphorylated (S)-tert-leucinol isophthalic diamide as a ligand for Pd-catalyzed asymmetric allylic substitution

et al. 2014

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O Phosphorylation of N,N´ (isophthaloyl)di (S) tert leucinol with (5S) 2 chloro 3 phenyl 1,3 diaza 2 phosphabicyclo[3.3.0]octane afforded bidentate phosphite type ligand. This ligand provided 93% ee in Pd catalyzed enantioselective allylation of (E) 1,3 diphenylallyl acetate, and 55% ee in alkylation of cinnamyl acetate with ethyl 2 oxocyclohexane 1 carb oxylate.Activity and stereoselectivity of metal complex cata lysts are mainly determined by the success in design and synthesis of the corresponding chiral ligands. Phospho rus containing chiral ligands repeatedly used in various asymmetric transformations are of special interest. 1-7 The metal complexes comprising the vast majority of chiral phosphorus ligands have proven to afford the excellent enantiomeric control only in certain chemical transfor mations. Only few ligands have a general scope (so called privileged ligands); moreover, a high cost of these ligands limited their wide applications. Consequently, the design of novel effective phosphorus containing chiral inductors readily accessible from enantiomerically pure building blocks is still urgent. 8-12One of the promising strategies to achieve this goal is the synthesis of ligands combining the advantages of or ganic and phosphorus chiral inductors. 13-15 The synthet ic approaches towards these ligands may involve either introduction of organocatalytic functional groups into the molecules of chiral phosphines or direct phosphorylation of different organocatalysts. For instance, thiourea P,P bi dentate ligand L A obtained via reaction of ferrocenyl aminobisphosphine with substituted phenyl isothiocyan ate shows excellent enantioselectivity in Rh catalyzed hydrogenation of nitroalkenes. 16 Amides derived from enantiomerically pure amino alcohols (these compounds are efficient organocatalysts for asymmetric reduction of ketimines with trichlorosilane and ketones with borane 17-20 ) can be regarded as suitable starting material for the introduction of the phosphorus chiral centers. Thus, phosphinite derivatives of diamides of oxalic acid with available chiral amino alcohols L B have been found to be effective in Ru catalyzed asymmetric transfer hydrogenation of aromatic ketones. 21-23 Howev er, the significant disadvantage of these compounds is their high sensitivity to oxidation and hydrolysis. 21

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“…These values suggest the anti-orientation of the pseudoequatorial exocyclic substituent at the phosphorus atom and the -(CH 2 ) 3 -part of the pyrrolidine fragment of the phosphabicyclic skeleton and, consequently, the synorientation of the phosphorus lone pair with respect to the C(8) atom (Figure 1). [13,18,[55][56][57][58][59] (S) In order to have an estimation of the steric bulk of ligands 4a-c and 5, we calculated their Tolman cone angles [60] by the reported method using semi-empirical quantum-mechanical AM1 techniques with full optimization of geometrical parameters. [61] The obtained results (Table 1) show that the steric parameters (q) of 4a-c and 5 vary within the interval of 121°-165°, peaking at diamidophosphite 4c.…”

Section: Resultsmentioning

confidence: 99%

Application of Hydroxyporphyrins-based Phosphite-type Ligands to Asymmetric Pd-Catalyzed Allylic Substitution Reactions

Konstantin¹,

Sergey²,

Marina³

et al. 2015

MHC

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Modular Synthesis of Novel Chiral Phosphorous Triamides Based on (S)‐N‐(Pyrrolidin‐2‐ylmethyl)aniline and Their Application in Asymmetric Catalysis

Cited by 54 publications

References 43 publications

Palladium-catalyzed allylic substitution assisted by 1,3,2-diazaphospholidine derivatives of (R,R)-N-naphthyltartarimide

Palladium-catalyzed allylic substitution assisted by 1,3,2-diazaphospholidine derivatives of (R,R)-N-naphthyltartarimide

Phosphorylated (S)-tert-leucinol isophthalic diamide as a ligand for Pd-catalyzed asymmetric allylic substitution

Application of Hydroxyporphyrins-based Phosphite-type Ligands to Asymmetric Pd-Catalyzed Allylic Substitution Reactions

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