100348-93-4Relevant articles and documents
Promotion of one-pot Robinson annelation achieved by gradual pressure and temperature manipulation under supercritical conditions
Kawanami, Hajime,Ikushima, Yutaka
, p. 5147 - 5150 (2004)
The one-pot Robinson annelation from 2-methyl-cyclohexane-1,3-dione with 3-buten-2-one can be achieved in high yield (95%) and high selectivity (95%) by pressure and temperature manipulation using supercritical carbon dioxide in the presence of MgO catalyst, whose method could be applied for various ketones to synthesize fused polycyclic compounds.
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Newkome,G.R. et al.
, p. 2098 - 2101 (1972)
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Synthesis and use of 3,3′-bimorpholine derivatives in asymmetric Michael addition and intramolecular aldol reaction
Sulzer-Mosse, Sarah,Laars, Marju,Kriis, Kadri,Kanger, Tonis,Alexakis, Alexandre
, p. 1729 - 1732 (2007)
The synthesis of 3,3′-bimorpholine and its N-alkyl derivatives is described. These new diamine derivatives were revealed to be efficient organocatalysts for the asymmetric Michael addition of aldehydes to nitroalkenes with excellent enantioselectivity (up to 90% ee). The potential of these organocatalysts was also demonstrated for the highly enantioselective intramolecular aldol reaction affording the Wieland-Miescher ketone with tremendous enantioselectivity (up to 95% ee). Georg Thieme Verlag Stuttgart.
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Scanio,C.J.V.,Hill,L.P.
, p. 651 - 652 (1970)
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One-pot synthesis of Wieland-Miescher ketone by enzymes
Lai, Yi-Feng,Zhang, Peng-Fei
, p. 4077 - 4082 (2015)
We first report that lipase from porcine pancreas catalyzed Robinson annulation in the organic media to synthesize the Wieland-Miescher ketone. The promiscuous catalytic activity of lipase in the Robinson reaction is due to an important role played by lipase activity in both the Michael addition and Aldol reaction.
Enantioselective synthesis of Wieland-Miescher ketone through bimorpholine-catalyzed organocatalytic aldol condensation
Kriis, Kadri,Kanger, T?nis,Laars, Marju,Kailas, Tiiu,Müürisepp, Aleksander-Mati,Pehk, T?nis,Lopp, Margus
, p. 1699 - 1702 (2006)
Novel bimorpholine-derived organocatalysts have been used for highly enantioselective intramolecular aldol reaction affording Wieland-Miescher ketone in high yield and enantioselectivity (up to 92% and 95%, respectively). Georg Thieme Verlag Stuttgart.
Recoverable silica-gel supported binam-prolinamides as organocatalysts for the enantioselective solvent-free intra- and intermolecular aldol reaction
Ba?ón-Caballero, Abraham,Guillena, Gabriela,Nájera, Carmen,Faggi, Enrico,Sebastián, Rosa María,Vallribera, Adelina
, p. 1307 - 1315 (2013)
Silica-gel supported binam-derived prolinamides are efficient organocatalysts for the direct intramolecular and intermolecular aldol reaction under solvent-free conditions using conventional magnetic stirring. These organocatalysts in combination with benzoic acid showed similar results to those obtained under similar homogeneous reaction conditions using an organocatalyst of related structure. For the intermolecular process, the aldol products were obtained at room temperature and using only 2 equiv of the ketone with high yields, regio-, diastereo- and enantioselectivities. Under these reaction conditions, also the cross aldol reaction between aldehydes is possible. The recovered catalyst can be reused up to nine times providing similar results. More interestingly, these heterogeneous organocatalysts can be used in the intramolecular aldol reaction allowing the synthesis of the Wieland-Miescher and ketone analogues with up to 92% ee, with its reused being possible up to five times without detrimental on the obtained results.
Total Synthesis of ent-Pregnanolone Sulfate and Its Biological Investigation at the NMDA Receptor
Kapras, Vojtech,Vyklicky, Vojtech,Budesinsky, Milos,Cisarova, Ivana,Vyklicky, Ladislav,Chodounska, Hana,Jahn, Ullrich
, p. 946 - 949 (2018)
A unique asymmetric total synthesis of the unnatural enantiomer of pregnanolone, as well as a study of its biological activity at the NMDA receptor, is reported. The asymmetry is introduced by a highly atom-economic organocatalytic Robinson annulation. A new method for the construction of the cyclopentane D-ring consisting of CuI-catalyzed conjugate addition and oxygenation followed by thermal cyclization employing the persistent radical effect was developed. ent-Pregnanolone sulfate is surprisingly only 2.6-fold less active than the natural neurosteroid.
Benzimidazole-pyrrolidine/H+ (BIP/H+), a highly reactive organocatalyst for asymmetric processes
Lacoste, Eric,Vaique, Emilie,Berlande, Muriel,Pianet, Isabelle,Vincent, Jean-Marc,Landais, Yannick
, p. 167 - 177 (2007)
A new chiral benzimidazole-pyrrolidine has been devised, which exhibits excellent activities in aminocatalyzed aldol reactions, leading to aldol products in high yields and enantioselectivities in the presence of an equimolar amount of a Broensted acid. This organocatalyst has demonstrated remarkable reactivities in aldol processes even with equimolar amounts of aldehyde and ketone in THF. A discussion of the role of the Broensted acid as a co-catalyst is provided along with some applications of this new class of organocatalyst in Robinson annelation and α-amination processes. Wiley-VCH Verlag GmbH & Co. KGaA, 2007.
Solid-supported Robinson annulation under microwave irradiation.
Takatori, Kazuhiko,Nakayama, Masayasu,Futaishi, Naoko,Yamada, Saori,Hirayama, Shinobu,Kajiwara, Masahiro
, p. 455 - 457 (2003)
Robinson annulation on alumina occurred efficiently on heating with microwave irradiation.
Assessing the Recyclability of Supramolecularly Assembled Organocatalytic Species: A Theoretical Insight
Llorens, Lluis,Llanes, Patricia,Fianchini, Mauro,Pericàs, Miquel A.
, p. 475 - 484 (2020)
Asymmetric organocatalytic synthesis is a powerful tool in organic chemistry to achieve desired stereoisomers in high purity via mild catalytic routes. The immobilization of homogeneous catalytic species onto heterogeneous phases embodies the evolution of asymmetric catalysis, since it allows the recycling of the catalyst for several runs until degradation. Previously reported non-covalent immobilization of proline-based catalysts for aldol reaction onto magnetic nanoparticles functionalized with β-cyclodextrin (MNP-β-CB) demonstrated the viability of the methodology. This paper proposes two new catalyst recycling strategies based on Cucurbit[7]uril (CB[7]) for the aldol reaction and the Robinson annulation. These recycling methodologies are conceptually different. The former relies on the homogeneous encapsulation of the catalyst in cucurbituril, CB[7] ? Cat, and its recycling in the aqueous phase by extraction of the aldol product with organic solvents. The latter relies on the heterogeneous encapsulation of the catalyst as MNP-CB[7] ? Cat2 system and its recycling by magnetic harvesting. Density functional theory (DFT) calculations have been employed to rationalize the thermodynamics of experimental results, and to suggest caveats and plausible improvements in view of a future catalytic design.
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Wendler et al.
, p. 3816 (1951)
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Structural constraints for C2-symmetric heterocyclic organocatalysts in asymmetric aldol reactions
Laars, Marju,Kriis, Kadri,Kailas, Tiiu,Mueuerisepp, Aleksander-Mati,Pehk, Tonis,Kanger, Tonis,Lopp, Margus
, p. 641 - 645 (2008)
Asymmetric aldol reactions were studied in the presence of heterocyclic bimorpholine- and bipiperidine-type organocatalysts. Bimorpholine derivatives were found to be more reactive and more selective in intramolecular, as well as intermolecular, reactions.
Kinetic and stereochemical evidence for the involvement of only one proline molecule in the transition states of proline-catalyzed intra- and intermolecular aldol reactions
Hoang, Lihn,Bahmanyar,Houk,List, Benjamin
, p. 16 - 17 (2003)
Contrary to the widely accepted mechanism of the Hajos-Parrish-Eder-Sauer-Wiechert reaction, we have obtained evidence for the involvement of only one proline molecule in the transition states of both inter- and intramolecular aldol reactions. Our conclusions are based on kinetic measurements and the absence of nonlinear and dilution effects on the asymmetric catalysis, and are supported by B3LYP/6-31G* calculations. Complementary to recent theoretical studies, our results provide the foundation of a unified enamine catalysis mechanism of proline-catalyzed inter- and intramolecular aldol reactions. Copyright
Asymmetric synthesis without solvent
Rajagopal, Desikan,Rajagopalan,Swaminathan
, p. 2189 - 2190 (1996)
Asymmetric syntheses of the diketones S-1, S-6, and S-10 from the precursors 3, 5 and 8 respectively have been carried out in the abscence of solvent employing S-proline as chiral auxiliary.
A Highly Active Polymer-Supported Catalyst for Asymmetric Robinson Annulations in Continuous Flow
Canellas, Santiago,Ayats, Carles,Henseler, Andrea H.,Pericàs, Miquel A.
, p. 1383 - 1391 (2017)
The preparation through Robinson annulation of enantiopure building blocks with both academic and industrial relevance, such as the Wieland-Miescher and Hajos-Parrish ketones, has suffered from important drawbacks, such as the need for high catalyst loading or extremely long reaction times. Here we report a heterogenized organocatalyst based on Luo's diamine for fast and broad-scope enantioselective Robinson annulation reactions. The polystyrene-supported diamine 19a enables the high-yield, highly enantioselective preparation of a wide range of chiral bicyclic enones under mild conditions, with reaction times as short as 60 min (batch) or residence times of 10 min (flow). In contrast with its homogeneous counterpart 19b, the catalytic resin 19a experiences a notable increase in catalytic activity with temperature in 2-MeTHF (a 10-fold decrease in reaction times without erosion in enantioselectivity is observed from room temperature to 55 °C). The scope of the transformation in batch mode has been illustrated with 14 examples, including examples only reported in poorly enantioenriched (22n) or in racemic form (22k). Enantiopure 22k has been used as the starting material for a straightforward formal synthesis of the antibiotic and antifeedant sesquiterpene (-)-isovelleral (24). The heterogenized catalyst 19a admits extended recycling (10 cycles) and has been used to develop the first asymmetric Robinson annulations in continuous flow. The potential of the flow process is illustrated by the large-scale preparation of the Wieland-Miescher ketone (65 mmol in 24 h of operation, TON of 117) and by a sequential flow experiment leading to a library of eight enantioenriched diketone compounds.
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Wieland,Miescher
, p. 2215,2224 (1950)
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Identification of Inhibitors of Cholesterol Transport Proteins Through the Synthesis of a Diverse, Sterol-Inspired Compound Collection
Laraia, Luca,Olsen, Asger Hegelund,Whitmarsh-Everiss, Thomas
supporting information, p. 26755 - 26761 (2021/11/17)
Cholesterol transport proteins regulate a vast array of cellular processes including lipid metabolism, vesicular and non-vesicular trafficking, organelle contact sites, and autophagy. Despite their undoubted importance, the identification of selective modulators of this class of proteins has been challenging due to the structural similarities in the cholesterol-binding site. Herein we report a general strategy for the identification of selective inhibitors of cholesterol transport proteins via the synthesis of a diverse sterol-inspired compound collection. Fusion of a primary sterol fragment to an array of secondary privileged scaffolds led to the identification of potent and selective inhibitors of the cholesterol transport protein Aster-C, which displayed a surprising preference for the unnatural-sterol AB-ring stereochemistry and new inhibitors of Aster-A. We propose that this strategy can and should be applied to any therapeutically relevant sterol-binding protein.
Hydrodealkenylative C(sp3)–C(sp2) bond fragmentation
Smaligo, Andrew J.,Swain, Manisha,Quintana, Jason C.,Tan, Mikayla F.,Kim, Danielle A.,Kwon, Ohyun
, p. 681 - 685 (2019/06/11)
Chemical synthesis typically relies on reactions that generate complexity through elaboration of simple starting materials. Less common are deconstructive strategies toward complexity—particularly those involving carbon-carbon bond scission. Here, we introduce one such transformation: the hydrodealkenylative cleavage of C(sp3)–C(sp2) bonds, conducted below room temperature, using ozone, an iron salt, and a hydrogen atom donor. These reactions are performed in nonanhydrous solvents and open to the air; reach completion within 30 minutes; and deliver their products in high yields, even on decagram scales. We have used this broadly functionality tolerant transformation to produce desirable synthetic intermediates, many of which are optically active, from abundantly available terpenes and terpenoid-derived precursors. We have also applied it in the formal total syntheses of complex molecules.
