Chemo- and regioselective reactions of 5-bromo enones/enaminones with pyrazoles
作者:Paulo A. Moraes、Marcio M. Lobo、Mário A. Marangoni、Alexandre R. Meyer、Clarissa P. Frizzo、Helio G. Bonacorso、Marcos A. P. Martins、Nilo Zanatta
DOI:10.1039/c9ob00234k
日期:——
with pyrazoles provided a series of unexpected N,O-aminal derivatives, through a 1,4-conjugated addition at the β-carbon of the 5-bromo enones instead of the expected nucleophilic substitution of the bromine. This reaction also furnished the 1,3-regioisomer of the pyrazole. A similar reaction of pyrazoles using 5-bromo enaminones furnished only N-alkylated pyrazoles—with high regioselectivity and at