I₂-Promoted site-selective C–C bond cleavage of aryl methyl ketones as C1 synthons for constructing 5-acyl-1<i>H</i>-pyrazolo[3,4-<i>b</i>]pyridines

Abstract

A novel iodine promoted [1 + 3 + 2] cleavage cyclization reaction for the synthesis of 1 H -pyrazolo[3,4- b ]pyridines from aryl methyl ketones, 5-aminopyrazoles and enaminones has been established.