Synthesis of 5,6-Dihydropyrazolo[5,1‑a]isoquinolines through Indium(III)-Promoted Halocyclizations of N‑Propargylic Sulfonylhydrazones

A novel method for the preparation of 5,6-dihydropyrazolo­[5,1-a]­isoquinoline via indium­(III)-promoted halocyclizations of N-propargylic sulfonylhydrazones has been developed. The pyrazole and 3,4-dihydroisoquinoline moieties were synchronously formed via a cascade cyclization reaction using easily assembled open-chain compounds. The pyrazole and 3,4-dihydroisoquinoline moieties were formed via a cascade cyclization reaction using easily assembled open-chain compounds.