Regioselective preparation of α-nitro cyclohexyl triisopropylsilyl enol ethers
摘要:
Treatment of the triisopropylsilyl enol ethers 1a-h with tetra-n-butyl ammonium nitrate and trifluoroaceric anhydride at 0 degrees C afforded the alpha-nitro triisopropylsilyl enol ethers 2a-h in 40-72% yield.
Hypervalent Iodine Chemistry: New Oxidation Reactions Using the Iodosylbenzene−Trimethylsilyl Azide Reagent Combination. Direct α- and β-Azido Functionalization of Triisopropylsilyl Enol Ethers
作者:Philip Magnus、Jérôme Lacour、P. Andrew Evans、Michael B. Roe、Christopher Hulme
DOI:10.1021/ja953906r
日期:1996.1.1
Treatment of triisopropylsilyl (TIPS) enolethers with PhIO/TMSN3/at −18 to −15 °C rapidly (5 min) gave β-azido TIPS enolethers in high yields, with only traces of the α-azido adduct. The reaction...
A Catalytic Intermolecular Formal Ene Reaction between Ketone-Derived Silyl Enol Ethers and Alkynes
作者:Stephen D. Holmbo、Nicole A. Godfrey、Joshua J. Hirner、Sergey V. Pronin
DOI:10.1021/jacs.6b06847
日期:2016.9.28
A catalytic formal ene reaction between ketone-derived silylenolethers and terminal alkynes is described. This transformation is uniquely capable of bimolecular assembly of 2-siloxy-1,4-dienes and can be used to access β,γ-unsaturated ketones containing quaternary carbons in the α-position.
A triflic imide (Tf(2)NH) catalyzed isomerization of kinetically favourable silyl enol ethers into thermodynamically stable ones was developed. We also demonstrated a one-pot catalytic reaction consisting of (2 + 2) cycloaddition and isomerization. In the reaction sequence, Tf(2)NH catalyzes both of the reactions.
For a series of 6-(4-methylphenylsulphonyl)amino-1-triisopropylsilyl(oxy)-cyclohexenes the preferred conformation, in the solid state, has the –NHTs (Ts = 4-methylphenylsulphonyl) group in an axial orientation; if the axial-NHTs group experiences a 1,3-diaxial interaction with a methyl group, the equatorial conformation becomes the thermodynamically more stable form.