457928-84-6Relevant academic research and scientific papers
Copper-Catalyzed Enantioselective Conjugate Addition to α,β-Unsaturated Aldehydes with Various Organometallic Reagents
Goncalves-Contal, Sylvie,Gremaud, Ludovic,Palais, La?titia,Babel, Lucille,Alexakis, Alexandre
, p. 3301 - 3308 (2016/09/12)
β-Substituted aldehydes constitute a very important class of compounds found in nature. Synthesis of this motif can be envisioned by C-C bond formation on enals. For this purpose, we report herein the development of enantioselective copper-catalyzed conjugate addition of various organometallic reagents to α,β-unsaturated aldehydes with (R)-H8BINAP, (R)-TolBINAP, and (R)-SEGPHOS as chiral ligands. Three sets of conditions were successfully developed and several enals were used. Reactivity and regio- and enantioselectivities were strongly dependent on reaction conditions and substrates. Good to excellent regio- and enantioselectivities were obtained with zinc reagents R2Zn and aluminum reagents R3Al. However, the asymmetric conjugate addition of Grignard reagents afforded only moderate to good regio- and enantioselectivities.
Copper-Catalyzed Asymmetric Conjugate Addition of Dimethylzinc to Acyl-N-methylimidazole Michael Acceptors: Scope, Limitations and Iterative Reactions
Drissi-Amraoui, Sammy,Schmid, Thibault E.,Lauberteaux, Jimmy,Crévisy, Christophe,Baslé, Olivier,de Figueiredo, Renata Marcia,Halbert, Stéphanie,Gérard, Hélène,Mauduit, Marc,Campagne, Jean-Marc
supporting information, p. 2519 - 2540 (2016/08/16)
An efficient copper-catalyzed enantioselective conjugate addition of dimethylzinc to unsaturated 2-acyl-N-methylimidazoles has been achieved using a chiral bidentate hydroxyalkyl-NHC ligand. The reactions proceed with excellent regioselectivity (1,4 vs. 1,6 and 1,8) in extended conjugated systems to afford the 1,4-adducts in high enantioselectivities. This regioselectivity could be ascertained by DFT studies highlighting the crucial role of the imidazole ring. Thanks to the development of efficient protocols to regenerate the unsaturated 2-acyl-N-methylimidazole moiety, an iterative process has been developed ultimately leading to 3,5,7 all-syn or anti-anti polydeoxypropionate stereodiads. (Figure presented.).
Effect of multinuclear copper/aluminum complexes in highly asymmetric conjugate addition of trimethylaluminum to acyclic enones
Endo, Kohei,Hamada, Daisuke,Yakeishi, Sayuri,Shibata, Takanori
, p. 606 - 610 (2013/02/23)
Al and friends: Asymmetric conjugate addition of Me3Al to β,β-disubstituted α,β-unsaturated ketones in the presence copper and L1 leads to a highly efficient construction of an all-carbon-substituted chiral quaternary center. This result is the first example of an asymmetric conjugate addition of Me3Al to acyclic enones to give a chiral quaternary carbon center with excellent yield and enantioselectivity under mild reaction conditions. Copyright
Enantioselective copper-catalyzed conjugate addition of trimethylaluminium to β,γ-unsaturated α-ketoesters
Gremaud, Ludovic,Alexakis, Alexandre
, p. 794 - 797 (2012/03/09)
Not a cop out: The copper-catalyzed asymmetric conjugate addition of organometallic reagents to Michael acceptors is an important methodology for forming a C-C bond in an enantioselective manner. Such an addition of Me 3Al to β,γ-unsaturated α-
Copper-catalyzed asymmetric conjugate addition to challenging michael acceptors and synthesis of relevant target molecules
Gremaud, Ludovic,Palais, Laetitia,Alexakis, Alexandre
scheme or table, p. 196 - 200 (2012/07/28)
We report herein the enantioselective Cu-catalyzed conjugate addition of organometallic reagents to sensitive Michael acceptors and their application to the synthesis of relevant target molecules. This is one of the most important methodologies to form a C-C bond in an enantioselective manner. A wide range of α,β-unsaturated aldehydes and β,γ-unsaturated-α- ketoesters has been successfully used. Reactivity, regioand enantioselectivities were strongly dependent on the reaction conditions, therefore moderate to very good results were obtained. Furthermore, γ-substituted-α-ketoesters were used as chiral building blocks for further derivatization with complete retention of the chiral information to obtain key compounds. Schweizerische Chemische Gesellschaft.
A new enantioselective catalytic route to Florhydral
Bovo, Sara,Scrivanti, Alberto,Bertoldini, Matteo,Beghetto, Valentina,Matteoli, Ugo
experimental part, p. 2547 - 2550 (2009/04/05)
The valuable fragrance Florhydral [3-(3-isopropylphenyl)butanal] has been synthesized in almost enantiomerically pure form by a new catalytic route. The key step of the process is the enantioselective hydrogenation of (E)-3-(3-isopropylphenyl)but-2-en-1-ol, which is carried out with asymmetric inductions of up to 97% using an iridium-phosphinooxazoline chiral catalyst. Georg Thieme Verlag Stuttgart.
Heck reactions of crotonaldehyde
Stadler, Michael,List, Benjamin
, p. 597 - 599 (2008/12/22)
A direct method for the synthesis of β,β-disubstituted-α, β-unsaturated aldehydes via Heck reaction of aryl halides with crotonaldehyde and related substrates has been developed. The reaction provides rapid access to products usually prepared via multistep sequences. The power of the method in combination with an organocatalytic transfer hydrogenation is illustrated with a short asymmetric synthesis of (S)-Florhydral. Georg Thieme Verlag Stuttgart.
