Divergent access to N-hydroxypyrroles and isoxazoles via the gold(I)-or Bronsted acid-catalysed regioselective cyclization of N-(2-trifluoromethyl-3-alkynyl) oximes

作者：Zeng, Qin; Zhang, Li; Xiao, Yuanjing^*; Zhang, Junliang^*

来源：Organic and Biomolecular Chemistry, 2018, 16(8): 1375-1380.

DOI：10.1039/c7ob03107f

• ONE-POT
• PYRROLES
• FACILE
• TRIFLUOROMETHYLATION
• CHROMOXYMYCIN
• CONDENSATION
• ACTIVATION
• REAGENTS
• NITRONES
• ALKYNES

The divergent regioselective cyclization of N-(2-trifluoromethyl-3-alkynyl) oximes by a suitable choice of a gold(I) or a Bronsted acid catalyst, leading to 4-trifluoromethyl-N-hydroxypyrroles or 4-trifluoromethyl-5-alkylisoxazoles was developed. In order to avoid the tedious separation of unstable N-(2-trifluoromethyl-3-alkynyl) oximes, an easy two-step, one-pot synthesis of 4-trifluoromethyl-5-alkylisoxazoles was realized via the sequential oxidation of the corresponding hydroxylamines and subsequent treatment with the reductant, sodium thiosulfate (Na2S2O3). This two-step, one-pot procedure is a complementary method for the synthesis of 4-trifluoromethyl-5-alkylisoxazole from those unstable N-(2-trifluoromethyl-3-alkynyl) oximes.

• 出版日期2018-2-28
• 单位复旦大学; 上海理工大学; 华东师范大学