Catalytic Enantioselective Addition of an Allyl Group to Ketones Containing a Tri-, a Di-, or a Monohalomethyl Moiety. Stereochemical Control Based on Distinctive Electronic and Steric Attributes of C–Cl, C–Br, and C–F Bonds
作者:Diana C. Fager、KyungA Lee、Amir H. Hoveyda
DOI:10.1021/jacs.9b08443
日期:2019.10.9
products enantioselectively but also in some cases there are hardly any instances of a catalytic enantioselectiveaddition of a carbon-based nucleophile (e.g., one enzyme-catalyzed aldol addition involving trichloromethyl ketones, and none with dichloromethyl, tribromomethyl, or dibromomethyl ketones). The approach is scalable and offers an expeditious route to the enantioselectivesynthesis of versatile
Formation of chiral fluoroalkyl products through copper-free enantioselective allylic alkylation catalyzed by an NHC ligand
作者:David Grassi、Hailing Li、Alexandre Alexakis
DOI:10.1039/c2cc36513h
日期:——
A valuable Cu-free protocol is reported where an NHC ligand has been employed to form quaternary carbon centers bearing fluoroalkyl units. The results obtained, from this allylic substitution, are better in terms of enantioselectivity and regioselectivity compared to the copper catalyzed system.
Decarboxylative fluorination of β-Ketoacids with N-fluorobenzenesulfonimide (NFSI) for the synthesis of α-fluoroketones: Substrate scope and mechanistic investigation
作者:Rui Zhang、Chuanfa Ni、Zhengbiao He、Jinbo Hu
DOI:10.1016/j.jfluchem.2017.08.010
日期:2017.11
Cesium carbonate (Cs2CO3)-mediated decarboxylativefluorination of β-ketoacids using NFSI in the MeCN/H2O mixed solvent system affords α-fluoroketones with a broad scope. Both electron-rich and electron-deficient α-non-substituted β-ketoacids are amenable to this protocol. The mechanistic study indicates that the reaction proceeds through electrophilic fluorination followed by decarboxylation, which
在MeCN / H 2 O混合溶剂体系中,使用NFSI进行碳酸铯(Cs 2 CO 3)介导的β-酮酸的脱羧氟化反应,可以得到范围很广的α-氟代酮。富含电子的和缺乏电子的α-非取代的β-酮酸均适用于该方案。机理研究表明,反应是通过亲电氟化反应继之以脱羧反应进行的,这不同于普通羧酸的脱羧氟化反应。
Synthesis of α-Fluoroketones by Insertion of HF into a Gold Carbene
an efficient synthesis of α‐fluoroketones by insertion of hydrogen fluoride (HF) into the gold carbene intermediate, generated from a cationicgold catalyzed addition of N‐oxides to alkynes. This method results in excellent chemical yields for a wide range of alkyne substrates and demonstrates good functional‐group tolerance.