The Catalytic Diels-Alder Reaction Using Combined Catalyst System of Diphenyltin Sulfide or Lawesson’s Reagent and Silver Perchlorate

Catalytic Diels-Alder reactions between several 1,3-dienes and α,β-unsaturated ketones are effectively promoted by the combined use of diphenyltin sulfide (Ph2Sn=S) and silver perchlorate or Lawesson’s reagent (2,4-bis(4-methoxyphenyl)-1,3-dithia-2,4-diphosphetane-2,4-disulfide) and silver perchlorate under mild conditions.