Diethylzinc-Mediated One-Step Stereoselective Synthesis of α-Fluoroacrylates from Aldehydes and Ketones. Two Different Pathways Depending on the Carbonyl Partner
摘要:
A efficient methodology allowing the one-pot stereoselective synthesis of alpha-fluoroacrylates, based on the addition of ethyl dibromofluoroacetate to a carbonyl derivative using diethylzinc as organometallic mediator, is described. Two different pathways have been identified depending on the involved carbonyl partner. In the case of aldehydes, an E2-type mechanism has been identified, whereas ketones go through an E1cb-type mechanism.
Diastereo- and Enantioselective Synthesis of Fluorine Motifs with Two Contiguous Stereogenic Centers
作者:Sudipta Ponra、Wangchuk Rabten、Jianping Yang、Haibo Wu、Sutthichat Kerdphon、Pher G. Andersson
DOI:10.1021/jacs.8b08778
日期:2018.10.24
motifs, in particular, chiral fluorine molecules with two contiguous stereogeniccenters, has attracted much interest in research due to the limited number of methods available for their preparation. Herein, we report an atom-economical and highlystereoselective synthesis of chiral fluorine molecules with two contiguous stereogeniccenters via azabicyclo iridium-oxazoline-phosphine-catalyzed hydrogenation
[EN] ARYL, HETEROARY, AND HETEROCYCLIC PHARMACEUTICAL COMPOUNDS FOR TREATMENT OF MEDICAL DISORDERS<br/>[FR] COMPOSÉS PHARMACEUTIQUES ARYLE, HÉTÉROARYLES ET HÉTÉROCYCLIQUES POUR LE TRAITEMENT DE TROUBLES MÉDICAUX
申请人:ACHILLION PHARMACEUTICALS INC
公开号:WO2018160889A1
公开(公告)日:2018-09-07
Complement Factor D inhibitors, pharmaceutical compositions, and uses thereof, as well as processes for their manufacture are provided. The compounds provided include Formula I, Formula II, Formula III, Formula IV, and Formula V, or a pharmaceutically acceptable salt, prodrug, isotopic analog, N-oxide, or isolated isomer thereof, optionally in a pharmaceutically acceptable composition. The inhibitors described herein target Factor D and inhibit or regulate the complement cascade.
Iridium Catalysts with Chiral Imidazole-Phosphine Ligands for Asymmetric Hydrogenation of Vinyl Fluorides and other Olefins
作者:Päivi Kaukoranta、Mattias Engman、Christian Hedberg、Jonas Bergquist、Pher G. Andersson
DOI:10.1002/adsc.200800062
日期:2008.5.5
New chiral bidentate imidazole-phosphine ligands have been prepared and evaluated for the iridium-catalysed asymmetric hydrogenation of olefins. The imidazole-phosphine-ligated iridiumcatalysts hydrogenated trisubstituted olefins with the same sense of enantiodiscrimination as known iridiumcatalysts possessing oxazole and thiazole as N-donors. The imidazole-based catalysts were shown to hydrogenate
E-selectivity was observed in the Horner-Wadsworth-Emmons (HWE) reactions of ethyl 2-fluoro-2-diethylphosphonoacetate 1 with alkyl aryl ketones 2a-f using Sn(OSO2CF3)2 and N-ethylpiperidine. Mg(II)-promoted HWE reactions of 1 with aldehydes 2h,i afforded α-fluoro-α,β-unsaturated esters 3h,i in a Z-selective manner depending on the reaction temperatures.
The synthesis of α-fluoroacrylates and α-bromo-α-fluoroalkenes was achieved in very good yields using aldehydes and ketones, triphenylphosphine, diethylzinc as promoter, and ethyl dibromofluoroacetate or dibromofluoromethane, respectively. A change in the addition sequence was critical in order to obtain exclusively α-fluoroacrylates in good yields.