A Modular Sydnone Cycloaddition/Suzuki-Miyaura Cross-Coupling Strategy to Unsymmetrical 3,5-Bis(hetero)aromatic Pyrazoles

作者:Delaunay Thierry; Genix Pierre; Es Sayed Mazen; Vors Jean Pierre; Monteiro Nuno*; Balme Genevieve
来源:Organic Letters, 2010, 12(15): 3328-3331.
DOI:10.1021/ol101087j

摘要

The [3 + 2] dipolar cycloaddition of 4-halosydnones with 1-haloalkynes opens a straightforward access to 3,5-dihalopyrazoles, valuable scaffolds for the elaboration of unsymmetrically 3,5-substituted pyrazole derivatives via site-selective Pd-catalyzed cross-coupling reactions. For instance, the flexible introduction of different (hetero)aryl substituents at the C-5 and C-3 positions of the PMP-protected pyrazole nucleus was achieved in a one-pot operation via sequential reactions with various boronic acids.

  • 出版日期2010-8-6