INVESTIGADORES
KAUFMAN Teodoro Saul
artículos
Título:
Wittig-Horner Mediated Synthesis of 4-Vinyl Sulfide Derivatives of Pyrazoles
Autor/es:
PADILHA, G.; KAUFMAN, T. S.; SILVEIRA, C. C.
Revista:
TETRAHEDRON LETTERS
Editorial:
PERGAMON-ELSEVIER SCIENCE LTD
Referencias:
Lugar: Amsterdam; Año: 2016
ISSN:
0040-4039
Resumen:
The synthesis of a series of 4-vinyl sulfide derivatives of 1,3-diarylpyrazoles, including their corresponding sulfoxides and sulfones, is reported. Access to the target vinyl sulfides was stereoselectively achieved, in moderate to good yields, by the n-BuLi-mediated Wittig-Horner reaction of 4-formylpyrazoles with arylthiophosphonates and á-chloro arylthiophosphonates in dimethoxyethane. Their oxidation with H2O2 in AcOH and mCPBA in CH2Cl2 afforded satisfactory yields of the expected vinyl sulfoxides and vinyl sulfones, respectively. Enrichment in the more stable isomers during both oxidation processes was detected and a plausible general mechanistic explanation was given to these observations.
