Construction of Sulfonyl Dihydrobenzo[c]xanthen-7-ones Core via NH4OAc/PdCl2/CuCl2‑Mediated Double Cyclocondensation of α‑Sulfonyl o‑Hydroxyacetophenones with 2‑Allylbenzaldehydes

NH4OAc/PdCl2/CuCl2 mediated domino double cyclocondensation of α-sulfonyl o-hydroxyacetophenones and 2-allylbenzaldehydes provides tetracyclic sulfonyl dihydrobenzo­[c]­xanthen-7-one core with good to excellent yields in MeOH. The intermediates contain a 3-sulfonyl flavanone motif. Only water is generated as a byproduct. The use of various catalysts and reaction conditions is studied for the facile-operational conversion.