Ionic Liquids as Precatalysts in the Highly Stereoselective Conjugate Addition of α,β‐Unsaturated Aldehydes to Chalcones

Ta, Linda; Axelsson, Anton; Bijl, Joachim; Haukka, Matti; Sundén, Henrik

doi:10.1002/chem.201404288

Cited by 26 publications

(26 citation statements)

References 55 publications

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“…Gels of these compounds were only obtained in water/DMSO and water/ethanol mixtures, which is not ideal for biological applications . Recently, we disclosed the multicomponent synthesis of OTHOs (Figure ) and their ability to form gels in hydrocarbon‐based solvents such as heptane and hexanes . Herein we report on the three‐component synthesis of OTHO‐based hydrogelators and their rheological properties.…”

Section: Figurementioning

confidence: 99%

“…The OTHO reaction is highly modular and in order to increase the hydrophilicity of the lipophilic OTHO backbone, hydrophilic groups were introduced on the four tunable positions of the OTHO backbone (the three aromatic rings Ar 1 , Ar 2 , Ar 3 and the ester R, see Scheme ). The three aromatic rings are capable of forming π–π interactions and are suspected to be the driving force behind the gelation of the OTHOs . Thus, introduction of pyridinium rings on the OTHO backbone will increase the water solubility and, potentially, also impact the gel properties by pyridinium–π interactions.…”

Section: Figurementioning

confidence: 99%

“…Derivatives 1 – 5 were obtained using the multi‐component synthesis of OTHOs starting from the corresponding chalcones, cinnamaldehydes and alcohols (Scheme ) . After a facile filtration and washing protocol, compounds 1 – 5 were obtained in high purity.…”

Section: Figurementioning

confidence: 99%

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A Multi‐Component Reaction towards the Development of Highly Modular Hydrogelators

Sauvée

Ström

Haukka

et al. 2018

Chemistry A European J

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Herein we report a multi-component reaction approach for the development of a new class of hydrogelators based on the OxoTriphenylHexanOate (OTHO) backbone. A focused library of OTHOs has been synthesized and their hydrogelation features evaluated. The two most potent hydrogelators were studied by rheology revealing different stiffness, appearances and thixotropic behavior of the gels. The new gelators showcase the versatility of the OTHO backbone as a platform for the design of functionalized hydrogels with tunable gel properties.

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Section: Figurementioning

confidence: 99%

Section: Figurementioning

confidence: 99%

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A Multi‐Component Reaction towards the Development of Highly Modular Hydrogelators

Sauvée

Ström

Haukka

et al. 2018

Chemistry A European J

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“…Analyze the resulting oil by 1 H NMR and 13 C NMR to check that EMIMAc is present. 24 3. Use the recycled EMIMAc starting from step 1.2.…”

Section: Recycling Of Emimacmentioning

confidence: 99%

“…The IL has been recycled up to five times with no decrease in reaction yield. 24 Moreover, the 1,6-ketoesters are also potent gelators in hydrocarbon solvents such as hexane and heptane (Figure 4). 29 The gelation is concentration dependent and ketoester 1 gelates already at a concentration of 2 mg/ml within 10 min.…”

confidence: 99%

Highly Stereoselective Synthesis of 1,6-Ketoesters Mediated by Ionic Liquids: A Three-component Reaction Enabling Rapid Access to a New Class of Low Molecular Weight Gelators

Sundén

Axelsson

2015

JoVE

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In organic chemistry ionic liquids (ILs) have emerged as safe and recyclable reaction solvents. In the presence of a base ILs can be deprotonated to form catalytically active N-Heterocyclic Carbenes (NHCs). Here we have used ILs as precatalysts in the addition of α,β-unsaturated aldehydes to chalcones to form 1,6-ketoesters, incorporating an anti-diphenyl moiety in a highly stereoselective fashion. The reaction has a broad substrate scope and several functional groups and heteroaromatics can be integrated into the ketoester backbone in generally good yields with maintained stereoselectivity. The reaction protocol is robust and scalable. The starting materials are inexpensive and the products can be obtained after simple filtration, avoiding solvent-demanding chromatography. Furthermore, the IL can be recycled up to 5 times without any loss of reactivity. Moreover, the 1,6-ketoester end product is a potent gelator in several hydrocarbon based solvents. The method enables rapid access to and evaluation of a new class of low molecular weight gelators (LMWGs) from recyclable and inexpensive starting materials.

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Hydroboration of aldehydes with pinacolborane catalyzed by bulky 2‐iminopyrrolyl copper(I) triphenylphosphine complexes

Cruz,

Figueira,

Gomes

2023

Applied Organom Chemis

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Eight new copper(I) triphenylphosphine complexes of bulky 5‐substituted‐2‐iminopyrrolyl ligands [Cu{κ2N,N′‐5‐R‐NC4H2–2‐C(H) = N(2,6‐iPr2C6H3)}(PPh3)n] (for n = 2: R = 2,6‐Me2C6H3 (1), 3,5‐(CF3)2C6H3 (2); for n = 1: R = 2,4,6‐iPr3C6H2 (3), CPh3 (4), 2,6‐(OMe)2C6H3 (5), 2,4,6‐Ph3C6H2 (6), 2,6‐Me2C6H3 (7), 3,5‐(CF3)2C6H3 (8)) are presently reported. The complexes were prepared in good yields by: (1) the reaction of the previously reported binuclear complexes [Cu{κN,κN'‐5‐R‐NC4H2‐2‐C(H) = N(2,6‐iPr2C6H3)}]2 (D1–D6) with triphenylphosphine (PPh3); (2) the reaction of the respective 5‐R‐2‐iminopyrrolyl potassium salts (KL1–KL3 and KL5) and [Cu(NCMe)2(PPh3)2]BF4; or (3) the abstraction of one PPh3 ligand present in complexes 1 and 2 with one equivalent of tris(pentafluorophenyl)borane (only for complexes 7 and 8, respectively). All complexes were characterized by NMR spectroscopy, elemental analysis and, in selected cases, by single crystal X‐ray diffraction. The single crystal X‐ray diffraction structures of 1, 3, and 5–7 displayed tetrahedral (for 1) and trigonal planar (for 3 and 5–7) coordination geometries. All complexes catalyzed the 1,4‐hydroboration of some α,β‐unsaturated (E)‐2‐enals with pinacolborane (HBPin), with 1,4:1,2‐addition selectivities as high as 29:1, the maximum turnover frequencies being equal to 9.9 min−1, and the 1,4‐hydroboration selectivity being favored by increasing steric protection of the 5‐substituted‐2‐iminopyrrolyl scaffold. Additionally, these complexes also catalyzed the hydroboration of an array of other aldehydes, reaching TOFs as high as 9.9 min−1. A combination of control experiments suggests that the catalyst system operates via a non‐classical copper‐hydride outer sphere route.

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Ionic Liquids as Precatalysts in the Highly Stereoselective Conjugate Addition of α,β‐Unsaturated Aldehydes to Chalcones

Cited by 26 publications

References 55 publications

A Multi‐Component Reaction towards the Development of Highly Modular Hydrogelators

A Multi‐Component Reaction towards the Development of Highly Modular Hydrogelators

Highly Stereoselective Synthesis of 1,6-Ketoesters Mediated by Ionic Liquids: A Three-component Reaction Enabling Rapid Access to a New Class of Low Molecular Weight Gelators

Hydroboration of aldehydes with pinacolborane catalyzed by bulky 2‐iminopyrrolyl copper(I) triphenylphosphine complexes

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