Previously reported CH-diazomethane sulfonamides carrying various propargylic groups are generated in situ from their acetyl precursors. Without purification, these compounds undergo a slow, albeit clean and efficient, intramolecular [3+2] cycloaddition to give pyrazole-fused five-membered sultams. The latter are the first analogues of medicinally important (hetero)arene-fused five-membered sultams containing a five-membered nitrogenous heterocycle. The newly introduced scaffold can be further elaborated into N-arylated derivatives using the Chan–Evans–Lam protocol. The resulting compounds incorporate more than one privileged moiety and are highly suitable for interrogation of protein targets via biological screening.
Key words
diazo compounds - sultams - pyrazoles - [3+2] intramolecular cycloaddition - Mitsunobu alkylation - Chan–Evans–Lam arylation
