Regioselective synthesis of highly substituted aromatic sulfides via carbonyl-alkyne exchange reaction

Carbonyl-alkyne exchange reaction of 2,2-dimethyldihydropyran-4-thione-deri ved dienes with acetylenic ketones leads to highly substituted aromatic sul fides. The reaction proceeds with a high degree of regioselectivity and in good yields. Addition of Et2AlCl considerably increases the scope of usable acetylenic ketones. The starting materials, dihydropyran-4-one and alpha-a lkynyl ketone derivatives, are readily available reactive building blocks. Additional diversity can be introduced through straightforward derivatizati on reactions at the sulfur atom. The use of solid-supported reagents and tr apping agents allows the reaction to be carried out in a parallel format wh ich might render such a concept attractive for the synthesis of compound li braries.