Gold-catalyzed synthesis of 1-isochromene-4-carbaldehydes oxidative cascade cyclization

An efficient gold-catalyzed formation of indenylidene-derived 1 H -isochromene-4-carbaldehydes from substituted 1,5,10-triyne- O -silanes was developed under mild reaction conditions. In this reaction, gold-catalyzed selective oxidation, 1,2-migration, nucleophilic addition and then 5- endo-dig cyclization took place regioselectively. The indenylidene-derived isochromene-4-carbaldehydes were synthesized in moderate to very good yields via the formation of new C-C and C-O bonds in one pot. An efficient gold-catalyzed formation of indenylidene-derived 1 H -isochromene-4-carbaldehydes from substituted 1,5,10-triyne- O -silanes was developed via selective oxidation, 1,2-migration, nucleophilic addition and regioselective 5- endo-dig cyclization.