1,3-γ-Silyl-elimination in electron-deficient cationic systems
作者:Michael A. Mercadante、Christopher B. Kelly、Trevor A. Hamlin、Kayla R. Delle Chiaie、Michael D. Drago、Katherine K. Duffy、Megan T. Dumas、Diana C. Fager、Bryanna L. C. Glod、Katherine E. Hansen、Cameron R. Hill、Rebecca M. Leising、Catherine L. Lynes、Allyson E. MacInnis、Madeline R. McGohey、Stephanie A. Murray、Marc C. Piquette、Shaina L. Roy、Ryan M. Smith、Katherine R. Sullivan、Bao H. Truong、Kristina M. Vailonis、Vitaliy Gorbatyuk、Nicholas E. Leadbeater、Leon J. Tilley
DOI:10.1039/c4sc01732c
日期:——
an electron-withdrawing trifluoromethyl group (–CF3) at a putative cationic centre enhances γ-silyl neighbouring-group participation (NGP). In stark contrast to previously studied γ-silyl-substituted systems, the preferred reaction pathway is 1,3-γ-silyl elimination, giving ring closure over solvent substitution or alkene formation. The scope of this cyclopropanation reaction is explored for numerous
The reaction of trifluoroacetaldehyde ethyl hemiacetal or hydrate with an equimolar amount of imine in hexane at reflux temperature for 1 h gave the corresponding β-hydroxy-β-trifluoromethyl ketones in good to excellent yields.
The Use of Trifluoroacetaldehyde Ethyl Hemiacetal or Hydrate in a Simple and Practical Regioselective Synthesis of β-Hydroxy-β-trifluoromethyl Ketones from Enamines and Imines
The reaction of trifluoroacetaldehyde ethyl hemiacetal or hydrate with an equimolar amount of enamines, derived from various methylketones, smoothly proceeded to give the corresponding beta-hydroxy-beta-trifluoromethyl ketones in high yields. An equimolar amount of imines derived from various methylketones with aliphatic, aromatic, and heteroaromatic substituents also readily reacted with trifluoroacetaldehyde