Facile Regioselective Synthesis of Pyrazolo[5,1-<i>a</i>]isoquinolines via Ring-Opening Cyclization/Oxidation Reactions of Stable Aroyldiaziridines of 3,4-Tetrahydroisoquinoline with Alkynes
作者:Howard Alper、Heriberto Ortega、Sara Ahmed
DOI:10.1055/s-2007-990888
日期:2007.12
4-tetrahydroisoquinolines undergo regioselective cycloaddition reactions with a number of both mono and disubstituted alkynes, affording five-membered ring products which, after oxidative aromatization of the pyrazoline ring, lead to the efficient preparation of pyrazolo[5,1-a]isoquinolines. The overall transformation is base-catalyzed and occurs more rapidly in the presence of oxygen, in halogenated
A novel copper-catalyzed oxidative formal [3 + 2] annulations of ketoximeacetates and tetrohydroisoquinolines for the synthesis of fused pyrazoles and imidazoles has been developed. A broad range of important isoquinoline-fused pyrazole and imidazole products were selectively generated by the key control of oxidant.