Cuts both ways: The title reaction consists of an addition/cyclization/dehydration sequence and affords the biologically important chiral 3,5‐diaryl‐5‐(trifluoromethyl)‐2‐isoxazolines 1 in excellent yields with high ee values. The flexibility of accessing either the S or R enantiomers of the products has been achieved by the appropriate choice of phase‐transfer catalyst (2).
Efficient and Highly Enantioselective Construction of Trifluoromethylated Quaternary Stereogenic Centers via High-Pressure Mediated Organocatalytic Conjugate Addition of Nitromethane to β,β-Disubstituted Enones
A very effective high-pressure-induced acceleration of asymmetric organocatalyticconjugateaddition of nitromethane to sterically congested β,β-disubstituted β-CF3 enones has been developed. A combination of pressure (8–10 kbar) and noncovalent catalysis with low-loading of chiral tertiary amine-thioureas (0.5–3 mol %) is shown to provide very efficient access to a wide range of γ-nitroketones containing
This work describes the optimization process for the synthesis of β-trifluoromethylated ketonesfrom trifluoromethylated allylicalcohols. This transformation proceeds through a ruthenium catalyzed isomerization under mild conditions with high atom economy. The effect of the CF3 group was analyzed and it provides fundamental insights into the isomerization reaction.
the 4,4,4-trifluorobut-2-en-1-ol system undermetal-freeconditions to afford the corresponding saturated ketones in high to excellent chemical yields using such a convenient and easy-to-handle base as DBU at the toluene refluxing temperature, and utilization of the corresponding optically active substrates unambiguously demonstrated that this transformation proceeded in a highly stereoselective fashion
A synthetic approach to chiral β‐CF3‐substituted saturated carbonyl compounds has been developed in which ruthenium complexes efficiently catalyze the redoxisomerization of CF3‐bearing allylicalcohols by an intramolecular suprafacial enantiospecific 1,3‐hydrogen transfer (see scheme). This method was used for the enantioselective synthesis of (S)‐CF3‐citronellol.