Catalytic asymmetric protonation of fluoro-enolic species: access to optically active 2-fluoro-1-tetralone
摘要:
Three racemic a-fluorinated benzyl beta-ketoesters have been synthesized by electrophilic fluorination with Selectfluor(TM). They were submitted to our well established palladium-mediated cascade reaction (deprotection, decarboxylation and protonation of the resulting enolic species) producing optically active alpha-fluoro ketones. With benzyl 2-fluoro-1-tetralone-2-carboxylate as substrate, (S)-(-)-2-fluoro-1-tetralone with up to 65% enantiomeric excess was obtained using quinine as the chiral base and Pd/C type 807104 from Merck as the heterogeneous catalyst. (C) 2003 Elsevier Ltd. All rights reserved.
Catalytic asymmetric protonation of fluoro-enolic species: access to optically active 2-fluoro-1-tetralone
摘要:
Three racemic a-fluorinated benzyl beta-ketoesters have been synthesized by electrophilic fluorination with Selectfluor(TM). They were submitted to our well established palladium-mediated cascade reaction (deprotection, decarboxylation and protonation of the resulting enolic species) producing optically active alpha-fluoro ketones. With benzyl 2-fluoro-1-tetralone-2-carboxylate as substrate, (S)-(-)-2-fluoro-1-tetralone with up to 65% enantiomeric excess was obtained using quinine as the chiral base and Pd/C type 807104 from Merck as the heterogeneous catalyst. (C) 2003 Elsevier Ltd. All rights reserved.
2,2′-Bipyridine-3,3′-dicarboxylic carbohydrate esters and amides. Synthesis and preliminary evaluation as ligands in Cu(II)-catalysed enantioselective electrophilic fluorination
作者:Aurélie Assalit、Thierry Billard、Stéphane Chambert、Bernard R. Langlois、Yves Queneau、Diane Coe
DOI:10.1016/j.tetasy.2009.02.050
日期:2009.3
A series of 10 new carbohydrate-substituted bipyridines were prepared from 2,2'-bipyridine-3,3'-dicarboxylic acid, itself easily available from ortho-phenanthroline. As a preliminary exploration of their use as chiral ligands, Cu(II)-catalysed asymmetric electrophilic fluorination of model beta-ketoesters using these simple and easily accessible chiral bipyridines was studied. Only modest enantioselectivity was observed in this reaction, although the ee was in a similar range as those provided by known and more elaborate ligands. (C) 2009 Elsevier Ltd. All rights reserved.
Enantioselective fluorination of β-ketoesters catalysed by complexes of new mono-oxazoline ligands
作者:Teng Niu、Xiping Han、Danfeng Huang、Ke-Hu Wang、Yingpeng Su、Yulai Hu、Ying Fu
DOI:10.1016/j.jfluchem.2015.02.017
日期:2015.7
A new kind of mono-oxazoline ligands which combined diaryl methyl units and chiral oxazoline units together using pyridine as linker was prepared. Their applications in enantioselective electrophilic fluorination of beta-ketoesters by NFSI were investigated, and the corresponding products were obtained in excellent yield (up to 90%) and good enantioselectivity (78%) in CH2Cl2 at -60 degrees C. (C) 2015 Elsevier B.V. All rights reserved.
Catalytic asymmetric protonation of fluoro-enolic species: access to optically active 2-fluoro-1-tetralone
作者:Markus A. Baur、Abdelkhalek Riahi、Françoise Hénin、Jacques Muzart
DOI:10.1016/s0957-4166(03)00585-8
日期:2003.9
Three racemic a-fluorinated benzyl beta-ketoesters have been synthesized by electrophilic fluorination with Selectfluor(TM). They were submitted to our well established palladium-mediated cascade reaction (deprotection, decarboxylation and protonation of the resulting enolic species) producing optically active alpha-fluoro ketones. With benzyl 2-fluoro-1-tetralone-2-carboxylate as substrate, (S)-(-)-2-fluoro-1-tetralone with up to 65% enantiomeric excess was obtained using quinine as the chiral base and Pd/C type 807104 from Merck as the heterogeneous catalyst. (C) 2003 Elsevier Ltd. All rights reserved.