It all adds up: The activation of aromatic isoxazoles with a nitro group at the 4‐position has enabled the first regio‐ and diastereoselective trifluoromethylation at the 5‐position of isoxazoles by nucleophilic addition using Me3SiCF3 (see scheme; DMF=N,N′‐dimethylformamide). The process was demonstrated with a broad range of 3,5‐aromatic, heteroaromatic and aliphatic substrates.
所有这些加起来:在4位上带有硝基的芳香异恶唑的活化,使得能够通过Me 3 SiCF 3的亲核加成在异恶唑的5位上进行第一次区域和非对映选择性的三氟甲基化(参见方案; DMF = N ,N'-二甲基甲酰胺)。广泛的3,5-芳族,杂芳族和脂族底物都证明了该方法。
Catalytic enantioselective addition of isocyanoacetate to 3-methyl-4-nitro-5-styrylisoxazoles under phase transfer catalysis conditions
作者:Paolo Disetti、Maria Moccia、Diana Salazar Illera、Surisetti Suresh、Mauro F. A. Adamo
DOI:10.1039/c5ob01880c
日期:——
The reaction between 3-methyl-4-nitro-5-styrylisoxazoles and ethyl isocyanoacetate proceeded under phasetransfercatalysis to give enantioenriched monoadducts in high enantiomeric excess (up to 99% ee). The resulting adducts were subsequently cyclised to give 2,3-dihydropyrroles and substituted pyrrolidines in identical high ees and as a single diastereoisomer.