Fluorinated Organocatalysts for the Enantioselective Epoxidation of Enals: Molecular Preorganisation by the Fluorine-Iminium Ion Gauche Effect
作者:Eva-Maria Tanzer、Lucie E. Zimmer、W. Bernd Schweizer、Ryan Gilmour
DOI:10.1002/chem.201201316
日期:2012.9.3
The fluorine‐iminium ion gauche effect is triggered upon union of a secondary β‐fluoroamine and an α,β‐unsaturated aldehyde, providing a useful strategy for controlling the molecular topology of intermediates that are central to organocatalytic processes. The β‐fluoroamine (S)‐2‐(fluorodiphenylmethyl)pyrrolidine (1) is an effective catalyst for the enantioselectiveepoxidation of α,β‐unsaturated aldehydes
This invention aims at providing a catalyst for producing an optically active aldehyde or an optically active ketone, which is an optically active carbonyl compound, by carrying out selective asymmetric hydrogenation of an α,β-unsaturated carbonyl compound, particularly a catalyst which is insoluble in a reaction mixture for obtaining optically active citronellal which is useful as a flavor or fragrance, by carrying out selective asymmetric hydrogenation of citral, geranial or neral; and a method for producing a corresponding optically active carbonyl compound. The invention relates to a catalyst for asymmetric hydrogenation of an α,β-unsaturated carbonyl compound, which comprises a powder of at least one metal selected from metals belonging to Group 8 to Group 10 of the Periodic Table, or a metal-supported substance in which at least one metal selected from metals belonging to Group 8 to Group 10 of the Periodic Table is supported on a support, an optically active cyclic nitrogen-containing compound and an acid.
Molecular Design Exploiting a Fluorine<i>gauche</i>Effect as a Stereoelectronic Trigger
作者:Yannick P. Rey、Lucie E. Zimmer、Christof Sparr、Eva-Maria Tanzer、W. Bernd Schweizer、Hans Martin Senn、Sami Lakhdar、Ryan Gilmour
DOI:10.1002/ejoc.201301730
日期:2014.2
Acyclic conformational control often relies on destabilising noncovalent interactions to give rise to predictable conformer populations. Pertinent examples of such strategies include allylicstrain (A1,2 and A1,3) and syn-pentane interactions. However, the incorporation of fluorine vicinal to an electron-withdrawing group (F–Cβ–Cα–X) can lead to predictable conformations as a consequence of stabilising
A Concise Synthesis of (S)-2-(Fluorodiphenylmethyl)pyrrolidine: A Novel Organocatalyst for the Stereoselective Epoxidation of α,β-Unsaturated Aldehydes
A concise synthesis of (S)-2-(fluorodiphenylmethyl)pyrrolidine from cheap, commercially available starting materials is described. Pertinent features of this synthetic route include ease of synthesis, facile purification steps, and an operationally simple deoxyfluorination step to install the C-F bond.
A synthesis of (S)-α-(fluorodiphenylmethyl)alkylamines by HF–pyridine treatment of 4-alkyl-5,5-diphenyl-oxazolidinones
作者:David O'Hagan、Frederique Royer、Mustafa Tavasli
DOI:10.1016/s0957-4166(00)00142-7
日期:2000.5
Treatment of enantiomerically pure (S)-4-alkyl-5,5-diphenyl-oxazolidinones, themselves derived from appropriate amino acids, with HF-pyridine (Olah's reagent) generated a range of (S)-alpha-(fluoro-diphenylmerhyl)alkylamines. These compounds represent a novel range of fluorinated chiral amines. (C) 2000 Elsevier Science Ltd. All rights reserved.