Facile deallylation protocols for the preparation of N-unsubstituted triazoles and tetrazoles.
Two facile deallylation protocols have been developed for the preparation of N-unsubstituted triazoles and tetrazoles. The first protocol is a direct deallylation using a combination of a catalytic amount of nickel complex, NiCl2(dppe), and a stoichiometric amount of Grignard reagent, tBuMgCl. The second protocol is a stepwise deallylation through consecutive reactions of isomerization and ozonolysis. The isomerization from N-allylazoles to N-vinylazoles is catalyzed by a ruthenium complex, HRuCl(CO)(PPh3)3, and the following ozonolysis of the derived N-vinyl intermediates affords N-unsubstituted azoles. These protocols can be used complementarily depending on the type of functional groups in the parent allylated azoles.
Kamijo
Shin
S
Department of Chemistry, Graduate School of Science, Tohoku University, Sendai 980-8578, Japan. skamijo@chem.fsu.edu
Huo
Zhibao
Z
Jin
Tienan
T
Kanazawa
Chikashi
C
Yamamoto
Yoshinori
Y