Pyrrolidine-Oxadiazolone Conjugates as Organocatalysts in Asymmetric Michael Reaction

Mahato, Chandan K.; Mukherjee, Sayan; Kundu, Mrinalkanti; Pramanik, Animesh

doi:10.1021/acs.joc.8b02393

Cited by 19 publications

(22 citation statements)

References 75 publications

(50 reference statements)

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“…Nitrile (4 S )- 4 or (4 R )- 4 (1.0 g, 4.7 mmol) was dissolved in MeOH (4.7 mL) and 3 N NaOH (4.7 mL, 14.1 mmol) and heated to 100 °C for one hour, at which time a homogeneous solution was obtained. The solution was cooled to room temperature and concentrated in vacuo to remove MeOH.…”

Section: Methodsmentioning

confidence: 99%

Synthesis and Stereochemical Assignment of Conioidine A: DNA- and HSA-Binding Studies of the Four Diastereomers

et al. 2020

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Conioidine A (1), isolated in 1993 with unknown relative and absolute configuration, was suggested to be a DNA-binding compound by an indirect technique. Four stereoisomers of conioidine A have been synthesized from D-and L-proline, and the natural product has been identified as possessing (4R,6R) absolute configuration. Binding of the conioidine diastereomers to calf thymus DNA (CT DNA) and human serum albumin (HSA) has been investigated by fluorescence spectroscopy and isothermal titration calorimetry (ITC). All stereoisomers display at least an order of magnitude weaker binding to DNA than the control compound netropsin; however, a strong association with HSA was observed for the (4R,6S) stereoisomer.

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Section: Methodsmentioning

confidence: 99%

Synthesis and Stereochemical Assignment of Conioidine A: DNA- and HSA-Binding Studies of the Four Diastereomers

et al. 2020

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“…Data ( syn ) agree with those reported in the literature. 11d Detected anti -isomer signals: δ = 7.19–7.13 (m, 2 H), 6.86–6.81 (m, 2 H), 4.79 (dd, J = 12.7, 9.7 Hz, 1 H), 3.93–3.87 (m, 1 H), 1.43–1.34 (m, 1 H).…”

Section: (2 R )-2-[(1 S )-1-(4-methox...mentioning

confidence: 99%

“…Data ( syn ) agree with those reported in the literature. 11d Detected anti -isomer signals: δ = 8.54–8.48 (m, 2 H), 7.67 (dt, J = 7.9, 1.9 Hz, 1 H), 4.91–4.83 (m, 2 H), 3.94–3.88 (m, 1 H), 2.80–2.72 (m, 1 H), 2.35–2.23 (m, 2 H), 1.97–1.87 (m, 1 H), 1.43–1.31 (m, 1 H).…”

Section: (2 R )-2-[(1 S )-2-nitro-1-p...mentioning

confidence: 99%

Amino Imidate Catalyzed Asymmetric Michael Reactions of Ketones and Nitroalkenes

Sosunovych¹,

Brown²,

Clarke³

2022

SynOpen

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The efficiency of an amino imidate organocatalyst was evaluated in the Michael reaction of ketones with nitroalkenes. tert-Butyl L-proline imidate was found to be a syn-selective catalyst generating products with moderate to good enantioselectivities, of up to 84% e.e. The best substrates were found to be cyclic ketones and -nitrostyrenes. The catalytic efficiency and enantioselectivity was enhanced by the addition of 10 mol% of benzoic acid.

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“…In view of developing a new generation of organocatalysts to be effective only in aqueous medium, we recently have shown that a novel pyrrolidine–oxadiazolone conjugate can successfully give the desired Michael adduct from nitrostyrene and cyclohexanone with >97:3 diastereoselectivity in water as a sole medium, although the enantiomeric excess for the syn isomer was found to be only 87% . The use of proline and proline derivatives as catalysts of multicomponent reactions performed in aqueous media has been summarized in a recent review .…”

Section: Introductionmentioning

confidence: 96%

Asymmetric 1,4-Michael Addition in Aqueous Medium Using Hydrophobic Chiral Organocatalysts

et al. 2021

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Organic transformations exclusively in water as an environmentally friendly and safe medium have drawn significant interest in the recent years. Moreover, transition metal-free synthesis of enantiopure molecules in water will have a great deal of attention as the system will mimic the natural enzymatic reactions. In this work, a new set of proline-derived hydrophobic organocatalysts have been synthesized and utilized for asymmetric Michael reactions in water as the sole reaction medium. Among the various catalysts screened, the catalyst 1 is indeed efficient for stereoselective 1,4-conjugated Michael additions (dr: >97:3, ee up to >99.9%) resulting in high chemical yields (up to 95%) in a very short reaction time (1 h) at room temperature. This methodology provides a robust, green, and convenient protocol and can thus be an important addition to the arsenal of the asymmetric Michael addition reaction. Upon successful implementation, the present strategy also led to the formation of an optically active octahydroindole, the key component found in many natural products.

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Pyrrolidine-Oxadiazolone Conjugates as Organocatalysts in Asymmetric Michael Reaction

Cited by 19 publications

References 75 publications

Synthesis and Stereochemical Assignment of Conioidine A: DNA- and HSA-Binding Studies of the Four Diastereomers

Synthesis and Stereochemical Assignment of Conioidine A: DNA- and HSA-Binding Studies of the Four Diastereomers

Amino Imidate Catalyzed Asymmetric Michael Reactions of Ketones and Nitroalkenes

Asymmetric 1,4-Michael Addition in Aqueous Medium Using Hydrophobic Chiral Organocatalysts

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