Chiral recyclable Cu(II)-catalysts in nitroaldol reaction of aldehydes with various nitroalkanes and its application in the synthesis of a valuable drug (R)-isoproterenol

Das, Anjan Kumar; Kureshy, Rukhsana I.; Prathap, K. Jeya; Choudhary, Manoj K.; Rao, Ganga V.S.; Khan, Noor‐ul H.; Abdi, Sayed H. R.; Bajaj, Hari C.

doi:10.1016/j.apcata.2013.03.032

Cited by 42 publications

(7 citation statements)

References 56 publications

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“…The highest s ‐value (>20) was obtained using cyclohexanecarboxylic anhydride ( 7 c ) (entry 3). The absolute configuration of the recovered nitroalcohol 5 a was determined to be S upon comparison of its experimental optical rotation with the previously reported value …”

Section: Resultsmentioning

confidence: 99%

Acylative Kinetic Resolution of Racemic 2,2‐Dimethyl‐Substituted Nitroaldol (Henry) Adducts Using a Chiral Guanidine Catalyst: (R)‐(+)‐N‐Methylbenzoguanidine ((R)‐NMBG)

2019

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Non‐enzymatic acylative kinetic resolution of racemic 2,2‐dimethyl‐substituted nitroaldol (Henry) adducts was achieved using cyclohexanecarboxylic anhydride in the presence of chiral guanidine catalyst. The systematic evaluation of the substituents on the aromatic rings of the substrates were conducted to clarify the influence of the substituents. The reaction was smoothly proceeded with moderate to good s‐values, regardless of the kinds of the substituents. Based on the absolute configuration of the resulted product, the transition state of the reaction was predicted, and it was important the interaction between the nitro group on the substrate and the cation face of the acyl‐guanidium intermediate to determine the direction of the substrate.

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Section: Resultsmentioning

confidence: 99%

Acylative Kinetic Resolution of Racemic 2,2‐Dimethyl‐Substituted Nitroaldol (Henry) Adducts Using a Chiral Guanidine Catalyst: (R)‐(+)‐N‐Methylbenzoguanidine ((R)‐NMBG)

2019

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“…We therefore considered testing the ability of the corresponding reduced salen derivatives to act likewise as potential ligands to promote this reaction, with the aim of preparing more stable complexes possessing increased nitrogen basicity and framework flexibility (see scheme 8). [26]…”

Section: Scheme 7: Homogeneous and Heterogeneous Epoxide Ring Openingmentioning

confidence: 99%

Chiral salen complexes in polymeric main‐chains for heterogeneous asymmetric catalysis – a brief account

Dandachi

Hong

Ibrahim

et al. 2020

Vietnam Journal of Chemistry

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This brief account summarizes our contribution to the field of heterogeneous asymmetric catalysis with salen complexes. We have developed two different procedures to immobilize these highly efficient catalysts in polymeric main chains for multiple reasons. These heterogenized structures possess indeed solubility properties allowing their easy recovery by simple filtration. Furthermore, by avoiding the use of large either organic or inorganic supports, the introduced catalytic mass does not so much differ from the homogeneous one. Finally, catalytic sites location is precisely controlled, a parameter of major importance for some reactions in which bimetallic activation is needed. Their use and efficiency as insoluble catalysts is here described for the promotion of C‐O and C‐C bonds formation, with a specific emphasis on their reusability and cooperativity.

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“…Anti ‐selective reaction in basic conditions is reported by Ooi and co‐workers and later reported by other researchers . Salen ligands are one of the most privileged ligands for the asymmetric catalysis, and Cu (II) complexes of salen and salan ligands were largely used for nitro‐aldol reaction and efficiently active at mild reaction conditions . ( S )‐Proline‐based single chiral center salalen and salan ligands were first reported by Katsuki and co‐workers for the asymmetric epoxidation of non‐functionalised alkenes .…”

Section: Introductionmentioning

confidence: 96%

“…[53][54][55][56][57][58][59][60][61] Salen ligands are one of the most privileged ligands for the asymmetric catalysis, and Cu (II) complexes of salen and salan ligands were largely used for nitro-aldol reaction and efficiently active at mild reaction conditions. [62][63][64][65][66][67][68][69][70][71][72] (S)-Proline-based single chiral center salalen and salan ligands were first reported by Katsuki and co-workers for the asymmetric epoxidation of non-functionalised alkenes. 73 These ligands were also used by Kol and co-workers for polymerisation of α-olefins and stereoselective polymerization of lactide.…”

Section: Introductionmentioning

confidence: 99%

Synthesis of chiral salalen ligands and their in‐situ generated Cu‐complexes for asymmetric Henry reaction

2018

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Chiral salalen ligands derived from (S)‐proline and derivatives of salicyaldehydes were synthesized, and their in‐situ generated Cu (II) complexes were evaluated in the asymmetric Henry reaction. Salalen ligand of different substituents on the phenyl moiety showed remarkable effect on the enantioselectivity of nitro‐aldol product of 4‐nitrobenzaldehyde and nitromethane. Cu (II) complex generated in situ with (S)‐2‐(tert‐butyl)‐6‐((2‐(((2‐hydroxy‐3‐methylbenzylidene)amino)methyl)pyrrolidin‐1‐yl)methyl) phenol (10 mol%) and Cu (OAc)2.H2O (10 mol%), found to be better catalyst for nitro‐aldol reaction between 4‐nitrobenzaldehyde and nitromethane, gave corresponding product in 85% yield and 88% enantiomeric excess (ee) in isopropanol at 35°C after 40 hours. The catalyst also used for the Henry reaction with different substituted benzaldehydes and corresponding products were obtained in 22% to 99% yields with 66% to 92% ee. Henry reaction of 4‐nitrobenzaldehyde and prochiral nitroethane gave anti‐selective product (dr = 79/21; anti/syn) in a 91% yield with 80% ee.

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Chiral recyclable Cu(II)-catalysts in nitroaldol reaction of aldehydes with various nitroalkanes and its application in the synthesis of a valuable drug (R)-isoproterenol

Cited by 42 publications

References 56 publications

Acylative Kinetic Resolution of Racemic 2,2‐Dimethyl‐Substituted Nitroaldol (Henry) Adducts Using a Chiral Guanidine Catalyst: (R)‐(+)‐N‐Methylbenzoguanidine ((R)‐NMBG)

Acylative Kinetic Resolution of Racemic 2,2‐Dimethyl‐Substituted Nitroaldol (Henry) Adducts Using a Chiral Guanidine Catalyst: (R)‐(+)‐N‐Methylbenzoguanidine ((R)‐NMBG)

Chiral salen complexes in polymeric main‐chains for heterogeneous asymmetric catalysis – a brief account

Synthesis of chiral salalen ligands and their in‐situ generated Cu‐complexes for asymmetric Henry reaction

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