Monohydrochloride Assisted Synthesis of Functionalized Isoxazoles and Pyrazoles from Allenic Ketones: First Synthesis of (Z)-2-Methyl-7H-benzo[b]pyrazolo[5,1-d][1,5]oxazocines

摘要

A facile hydrochloride promoted regioselective synthesis of isoxazoles and pyrazoles from 1,2-allenic ketones is reported. The reaction has been scaled up to gram scale. A direct 8-endo dig ring annulations towards the first synthesis of (Z)-2-methyl-7H-benzo[b]pyrazolo[5,1-d][1,5]oxazocine has been developed.