Synthesis of chiral atropoisomeric square-planar nickel(II) and copper(II) complexes formed by macrocyclic ligands containing pendant polyether groups and a quaternary ammonium group

Belokoń, Yuri N.; Pritula, Ludmila K.; Tararov, Vitali I.; Bakhmutov, Vladimir I.; Struchkov, Yuri T.; Timofeeva, Tatiana V.; Belikov, V. M.

doi:10.1039/dt9900001867

Cited by 13 publications

(6 citation statements)

References 26 publications

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“…It was reduced with LiAlH 4 in THF at reflux for 18 h to afford diamine 24 a (620 mg, 45 %). 1 H NMR: δ = 1.37 (br s, 4 H, 2×NH 2 ), 2.81 (dd, J =12.6, 7.1 Hz, 1 H, 2‐C H H), 2.92 (dd, J =12.6, 5.3 Hz, 1 H, 2‐CH H ), 3.89 (dd, J =7.1, 5.3 Hz, 1 H, 1‐CH), 7.23–7.34 (m, 5 H, Ph); MS (ES): m / z : 137 [ M +H] + , in agreement with the literature data 18.…”

Section: Methodssupporting

confidence: 89%

“…Synthesis of ligands 12 a – d : Ligand ( R )‐ 12 a (Scheme ) was readily prepared by conversion of methyl phenylglycinate ( R )‐ 22 a into amide ( R )‐ 23 a (aq. NH 3 , toluene; 70 %),17 followed by reduction (LiAlH 4 , THF; 45 %),18 and transformation of the resulting diamine ( R )‐ 24 a into the desired bisamide ( R )‐(−)‐ 12 a [α‐picolinic acid, (PhO) 3 P, pyridine, 100 °C, overnight; 62 %] 19. 20 The remaining members of the series, that is, ( S )‐ 12 b – d , were synthesized in a similar fashion.…”

Section: Resultsmentioning

confidence: 99%

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Asymmetric Allylic Substitution Catalyzed by C₁‐Symmetrical Complexes of Molybdenum: Structural Requirements of the Ligand and the Stereochemical Course of the Reaction

Malkov

Gouriou

Lloyd‐Jones

et al. 2006

Chemistry A European J

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Application of new chiral ligands (R)-(-)-12 a and (S)-(+)-12 c (VALDY), derived from amino acids, to the title reaction, involving cinnamyl (linear) and isocinnamyl (branched) type substrates (4 and 5 --> 6), led to excellent regio- and enantioselectivities (>30:1, < or =98 % ee), showing that ligands with a single chiral center are capable of high asymmetric induction. The structural requirements of the ligand and the mechanism are discussed. The application of single enantiomers of deuterium-labeled substrates (both linear 38 c and branched 37 c) and analysis of the products (41-43) by (2)H{(1)H} NMR spectroscopy in a chiral liquid crystal matrix allowed the stereochemical pathways of the reaction to be distinguished. With ligand (S)-(+)-12 c, the matched enantiomer of branched substrate was found to be (S)-5, which was converted into (R)-6 with very high regio- and stereoselectivity via a process that involves net retention of stereochemistry. The mismatched enantiomer of the branched substrate was found to be (R)-5, which was also converted into (R)-6, that is, with apparent net inversion, but at a lower rate and with lower overall enantioselectivity. This latter feature, which may be termed a "memory effect", reduced the global enantioselectivity in the reaction of the racemic substrate (+/-)-5. The stereochemical pathway of the mismatched manifold has been shown also to be one of net retention, the apparent inversion occurring through equilibration via an Mo-allyl intermediate prior to nucleophilic attack. Incomplete equilibration leads to the memory effect and thus to lower enantioselectivity. Analysis of the mismatched manifold over the course of the reaction revealed that the memory effect is progressively attenuated with the nascent global selectivity increasing substantially as the reaction proceeds. The origin of this effect is suggested to be the depletion of CO sources in the reaction mixture, which attenuates turnover rate and thus facilitates greater equilibrium. The linear substrate was also converted into the branched product with net syn stereochemistry, as shown by isotopic labeling. An analogous process operates in the generation of small quantities of linear product from branched substrate.

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Section: Methodssupporting

confidence: 89%

Section: Resultsmentioning

confidence: 99%

Asymmetric Allylic Substitution Catalyzed by C₁‐Symmetrical Complexes of Molybdenum: Structural Requirements of the Ligand and the Stereochemical Course of the Reaction

Malkov

Gouriou

Lloyd‐Jones

et al. 2006

Chemistry A European J

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“…The addition of NiCl 2 ⋅6 H 2 O and NaBH 4 directly to the bio‐transformation medium after the OYE‐mediated reduction of model compound ( Z )‐ 2 a without the isolation of the intermediate (−)‐ 1 a (Scheme ) afforded the complete conversion of the nitro moiety into a primary amine. After work‐up, the crude product was acetylated with acetic anhydride in pyridine to give (−)‐( R )‐ 4 . The conversion of (−)‐ 1 a into (−)‐( R )‐ 4 confirmed the R absolute configuration assigned to the product of the OYE‐mediated reduction.…”

Section: Resultsmentioning

confidence: 92%

“…After work‐up, purification by column chromatography ( n ‐hexane with increasing amounts of EtOAc) gave compound ( R )‐ 4 (38.8 mg, 72 %): [α] D =−84.0 ( c =0.5, EtOH), Ref. for ( R )‐ 4 [α] D =−83.3 ( c= 0.12, EtOH); 1 H NMR (CDCl 3 , 400 MHz): δ =7.42–7.20 (m, 5 H, ArH), 6.95 (br s, 1 H, NH ), 6.37 (br s, 1 H, NH ), 5.06 (m, 1 H, CH NH), 3.73 (ddd, 1 H, J= 14.1, 9.8, and 4.3 Hz, CH HNH), 4.73 (dt, 1 H, J= 14.1, and 4.3 Hz, CH HNH), 2.00 (s, 3 H, CH 3 CO), 1.98 ppm (s, 3 H, CH 3 CO); 13 C NMR (CDCl 3 , 100.6 MHz): δ =172.2, 170.9, 139.4, 129.0, 128.0, 126.6, 55.1, 45.1, 23.4, 23.3 ppm; GC–MS (EI) t R =25.29 min, m / z (%)=220 [ M + ] (2), 148 (52), 106 (100).…”

Section: Methodsmentioning

confidence: 99%

Asymmetric Bioreduction of β‐Acylaminonitroalkenes: Easy Access to Chiral Building Blocks with Two Vicinal Nitrogen‐Containing Functional Groups

et al. 2017

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The reduction of (Z)‐β‐acylaminonitroalkenes catalyzed by ene‐reductases is described for the first time. The reaction occurs with a high conversion and excellent enantioselectivity and shows a wide substrate scope. The reduced products are valuable chiral synthons characterized by two vicinal nitrogen‐containing functional groups that can be further modified by functional group inter‐conversion thanks to the synthetic versatility of the nitro moiety. The chemo‐enzymatic synthesis of (R)‐N,N′‐(1‐phenylethane‐1,2‐diyl)diacetamide from easily accessible (Z)‐N‐(2‐nitro‐1‐phenylvinyl)acetamide is herein reported as a representative application of this synthetic procedure.

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“…All analytical data are in agreement with the literature. 18 The enantiomeric excess was determined by HPLC (chiral stationary phase, Daicel Chiralcel OJ-H column, eluent hexane/i-PrOH 9:1, flow rate 0.8 mL/min, λ = 210 nm): t R = 9 (minor), 10.4 min (major). In all the cases the enantiomeric excess was maintained during the reduction of the nitro group.…”

Section: Feature Syn Thesis (S)-nn′-diacetyl-1-phenylethane-12-diammentioning

confidence: 99%

A Continuous-Flow, Two-Step, Metal-Free Process for the Synthesis of Differently Substituted Chiral 1,2-Diamino Derivatives

et al. 2018

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The enantioselective organocatalytic reduction of aryl-substituted nitroenamines was successfully performed under continuous-flow conditions. After a preliminary screening with a 10-μL microreactor, to establish the best reaction conditions, the reduction was scaled up in a 0.5-mL mesoreactor, without appreciable loss of enantioselectivity, that remained constantly higher than 90%. The in-flow nitro reduction was also accomplished, either by Raney nickel catalyzed hydrogenation or by a metal-free methodology based on the use of the very inexpensive and readily available reducing agent trichlorosilane. The final aim is to develop a two-step, continuous-flow process for the stereoselective, metal-free, catalytic synthesis of differently functionalized chiral 1,2-diamines.

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Synthesis of chiral atropoisomeric square-planar nickel(II) and copper(II) complexes formed by macrocyclic ligands containing pendant polyether groups and a quaternary ammonium group

Cited by 13 publications

References 26 publications

Asymmetric Allylic Substitution Catalyzed by C₁‐Symmetrical Complexes of Molybdenum: Structural Requirements of the Ligand and the Stereochemical Course of the Reaction

Asymmetric Allylic Substitution Catalyzed by C₁‐Symmetrical Complexes of Molybdenum: Structural Requirements of the Ligand and the Stereochemical Course of the Reaction

Asymmetric Bioreduction of β‐Acylaminonitroalkenes: Easy Access to Chiral Building Blocks with Two Vicinal Nitrogen‐Containing Functional Groups

A Continuous-Flow, Two-Step, Metal-Free Process for the Synthesis of Differently Substituted Chiral 1,2-Diamino Derivatives

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Synthesis of chiral atropoisomeric square-planar nickel(II) and copper(II) complexes formed by macrocyclic ligands containing pendant polyether groups and a quaternary ammonium group

Cited by 13 publications

References 26 publications

Asymmetric Allylic Substitution Catalyzed by C1‐Symmetrical Complexes of Molybdenum: Structural Requirements of the Ligand and the Stereochemical Course of the Reaction

Asymmetric Allylic Substitution Catalyzed by C1‐Symmetrical Complexes of Molybdenum: Structural Requirements of the Ligand and the Stereochemical Course of the Reaction

Asymmetric Bioreduction of β‐Acylaminonitroalkenes: Easy Access to Chiral Building Blocks with Two Vicinal Nitrogen‐Containing Functional Groups

A Continuous-Flow, Two-Step, Metal-Free Process for the Synthesis of Differently Substituted Chiral 1,2-Diamino Derivatives

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Product

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Asymmetric Allylic Substitution Catalyzed by C₁‐Symmetrical Complexes of Molybdenum: Structural Requirements of the Ligand and the Stereochemical Course of the Reaction

Asymmetric Allylic Substitution Catalyzed by C₁‐Symmetrical Complexes of Molybdenum: Structural Requirements of the Ligand and the Stereochemical Course of the Reaction