Cobalt-catalyzed regioselective hydrohydrazination of epoxides
作者:Xiangyu Liu、Heng Song、Xiaofang Zhai、Chen-Ho Tung、Wenguang Wang
DOI:10.1039/d0ob00037j
日期:——
= Me5C5-), we have achieved catalytic regioselective hydrohydrazination of epoxides to 1,1-hydrazinoalcohols in an atom-economical manner. The catalysis involves a cobalt-hydrazine intermediate, in which the NH2 group of the hydrazine binds to the metal center, inhibiting its nucleophilic reactivity and allowing the NH group to participate in the regioselective hydrohydrazination.
The oxidation of N-aminophthalimide (1) with lead tetraacetate in the presence of the phenylazoalkenes 2 afforded 2-phenylazo-1-(N-phthalimido)aziridines 3 or 2- phenyl[1,2,3]triazoles 7, as well as phthalimide (4). The reaction of 2-phenylazo-1-propene (2d) produced 5-methyl-2-phenyl-[1,2,3]triazole (7d) and N-[2-(phenylhydrazono)propylidene-amino]phthalimide (8d). The cyclic azoalkene 3,3,5-trimethyl-3H-pyrazole (11) gave a mixture of (Z)-3,3,5-trimethyl-[N-(phthalimido)amino]-3H-pyrazol-1-ium-2N-ide [(Z)-12] together with the regioisomers (E)- and (Z)-3,3,5-trimethyl-1-[N-(phthalimido)amino]-3H-pyrazol-2-ium-1N-ides [(E)- and (Z)-13].
DALLA CROCE P.; ZANIBONI A., SYNTHESIS, 1977, NO 8, 552