20007-98-1Relevant academic research and scientific papers
Highly enantioselective organocatalysis of the Hajos-Parrish-Eder-Sauer- Wiechert reaction by the β-amino acid cispentacin
Davies, Stephen G.,Sheppard, Ruth L.,Smith, Andrew D.,Thomson, James E.
, p. 3802 - 3804 (2005)
The β-amino acid cispentacin promotes the Hajos-Parrish-Eder-Sauer- Wiechert reaction with levels of enantioselectivity comparable to or higher than proline. The Royal Society of Chemistry 2005.
Desymmetrisation of: Meso -diones promoted by a highly recyclable polymer-supported chiral phosphoric acid catalyst
Clot-Almenara, Lidia,Rodríguez-Escrich, Carles,Pericàs, Miquel A.
, p. 6910 - 6914 (2018/02/23)
A polystyrene-supported BINOL-derived chiral phosphoric acid has been applied to the desymmetrisation of meso-diones to produce enantioenriched cyclohexenones. The catalytic resin has proven highly active and robust, giving rise to Hajos-Parrish or Wieland-Miescher type products in good yields and enantioselectivities, while allowing for extended recycling.
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 (2017/08/09)
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.
Lipase-catalyzed domino Michael-aldol reaction of 2-methyl-1,3-cycloalkanedione and methyl vinyl ketone for the synthesis of bicyclic compounds
Sano, Kaoru,Kohari, Yoshihito,Nakano, Hiroto,Seki, Chigusa,Takeshita, Mitsuhiro,Tokiwa, Micho,Hirose, Yoshihiko,Uwai, Koji
supporting information, p. 46 - 54 (2016/01/09)
Synthesis of bicyclic compounds was achieved via a lipase-catalyzed, stereoselective, domino Michael-aldol reaction of 2-methyl-1,3-cycloalkanedione and methyl vinyl ketone. Appropriate reaction conditions, including the type of enzyme, solvent, and temperature, were determined. In addition, the effects of solvent polarity and addtives were investigated. The reaction proceeded in the presence of lipase AS in a solution of 20% acetone in dimethylsulfoxide (DMSO) at 10 °C for 8 days, followed by the addition of p-toluenesulfonic acid (TsOH) to afford bicyclic compounds in 51-83% yields with moderate stereoselectivity. Although this domino Michael-aldol reaction showed only moderate stereoselectivity, even with the acid-supported enhancement of the reaction, these results represent potential new applications for lipase.
Pyrimidine-derived prolinamides as recoverable bifunctional organocatalysts for enantioselective inter- and intramolecular aldol reactions under solvent-free conditions
Vizcaíno-Milla, Pascuala,Sansano, José M.,Nájera, Carmen,Fiser, Béla,G?mez-Bengoa, Enrique
supporting information, p. 2614 - 2621 (2015/04/27)
Chiral L-prolinamides 2 containing the (R,R)- and (S,S)-trans-cyclohexane-1,2-diamine scaffold and a 2-pyrimidinyl unit are synthesized and used as general organocatalysts for intermolecular and intramolecular aldol reactions with 1,6-hexanedioic acid as a co-catalyst under solvent-free conditions. The intermolecular reaction between ketone-aldehyde and aldehyde-aldehyde must be performed under wet conditions with catalyst (S,S)-2b at 10 °C, which affords anti-aldols with high regio-, diastereo-, and enantioselectivities. For the Hajos-Parrish-Eder-Sauer-Wiechert reaction, both diastereomers of catalyst 2 give similar results at room temperature in the absence of water to give the corresponding Wieland-Miescher ketone and derivatives. Both types of reactions were scaled up to 1 g, and the organocatalysts were recovered by extractive workup and reused without any appreciable loss in activity. DFT calculations support the stereochemical results of the intermolecular process and the bifunctional role played by the organocatalyst by providing a computational comparison of the H-bonding networks occurring with catalysts 2a and 2b. The intermolecular ketone-aldehyde and aldehyde-aldehyde aldol reactions and the Hajos-Parrish-Eder-Sauer-Wiechert versions with the employment of chiral L-prolinamides containing the (R,R)- and (S,S)-trans-cyclohexane-1,2-diamine scaffold and a 2-pyrimidinyl unit are successfully performed under solvent-free conditions; WMK = Wieland-Miescher ketone.
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 (2013/02/23)
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.
Novel supported and unsupported prolinamides as organocatalysts for enantioselective cyclization of triketones
Pedrosa, Rafael,Andrés, José María,Manzano, Rubén,Pérez-López, César
supporting information, p. 3101 - 3104 (2013/06/27)
A novel prolylsulfonamide derived from ethylene diamine and its supported counterpart has been prepared and tested as enantioselective intramolecular aldol reaction of cyclic and acyclic triketones. Good to excellent yields and enantioselectivities have been obtained in water and under solvent free conditions.
A practical protocol for asymmetric synthesis of wieland-miescher and hajos-parrish ketones catalyzed by a simple chiral primary amine
Xu, Changming,Zhang, Long,Zhou, Pengxin,Luo, Sanzhong,Cheng, Jin-Pei
, p. 1939 - 1945 (2013/07/26)
This article describes a simple chiral primary amine catalyzed efficient and practical protocol for the large-scale synthesis of Wieland-Miescher and Hajos-Parrish ketones as well as their analogues. Georg Thieme Verlag Stuttgart. New York.
Asymmetric synthesis of Wieland-Miescher and Hajos-Parrish ketones catalyzed by an amino-acid-derived chiral primary amine
Zhou, Pengxin,Zhang, Long,Luo, Sanzhong,Cheng, Jin-Pei
, p. 2526 - 2530 (2012/05/05)
This paper describes a simple chiral primary amine-catalyzed highly efficient and practical protocol for the synthesis of both Wieland-Miescher ketone and Hajos-Parrish ketone as well as their analogues. The reaction can be conducted in gram scale with 1%
Proline imidazolidinones and enamines in Hajos-Wiechert and Wieland-Miescher ketone synthesis
de Arriba, ángel L. Fuentes,Simón, Luis,Raposo, César,Alcázar, Victoria,Morán, Joaquín R.
scheme or table, p. 4841 - 4845 (2009/10/02)
Readily available aromatic prolinamides obtained from the acid chloride of proline hydrochloride and anilines induce large enantiomeric excesses in intramolecular aldol condensations. Imidazolidinones derived from the reaction of the catalyst and enamines
