A novel synthetic approach to fluorine-containing acetylenic compounds based on Nicholas reaction
作者:Tsutomu Konno、Go Nagai、Takashi Ishihara
DOI:10.1016/j.jfluchem.2005.11.009
日期:2006.5
The fluorine-containing dicobalthexacarbonyl complex, prepared readily from γ-fluoroalkylated propargyl acetates and Co2(CO)8, reacted smoothly with various nucleophiles at the propargylic position, followed by oxidative decomplexation under the influence of Fe(NO3)3, to afford fluoroalkylated alkynes bearing various types of alkyl side chains in good to high yields.
Facile Preparation of CF3-Containing 1-Bromoallenes
作者:Takashi Yamazaki、Yohsuke Watanabe
DOI:10.1055/s-0029-1218383
日期:2009.12
The novel synthetic method is described for preparation of not only 1-bromo- but 1,3-dibromo-1-trifluoromethylated allenes from the corresponding propargylic alcohols with a combination of CBr4 and Ph3P. Selection of the organic solvent employed enabled us to access to these two different allenes quite readily.
Stereospecific Asymmetric N-Heterocyclic Carbene (NHC)-Catalyzed Redox Synthesis of Trifluoromethyl Dihydropyranones and Mechanistic Insights
作者:Alyn T. Davies、James E. Taylor、James Douglas、Christopher J. Collett、Louis C. Morrill、Charlene Fallan、Alexandra M. Z. Slawin、Gwydion Churchill、Andrew D. Smith
DOI:10.1021/jo401433q
日期:2013.9.20
N-Heterocyclic carbene (NHC)-catalyzed redox asymmetric hetero-Diels-Alder reactions of alpha-aroyloxyaldehydes with beta-trifluoromethyl enones generates synthetically useful dihydropyranones containing a stereogenic trifluoromethyl substituent in good yields (up to 81%) and excellent diastereoselectivity and enantioselectivity (up to >95:5 dr and >99% ee). The process is stereospecific, with use of either (E)- or (Z)-beta-trifluoromethyl enones forming syn- or anti-dihydropyranone products, respectively. Mechanistic studies through in situ kinetic analysis of the reaction reveal key differences in reactivity between chiral NHC precursor 1 and an achiral NHC precursor.