Palladium-catalyzed functionalization of indoles with 2-acetoxymethyl-substituted electron-deficient alkenes

A new functionalization of indoles through the Pd[(OAc).sub.2]-catalyzed reaction of indoles with 2-acetoxymethyl-substituted electron-deficient alkenes to afford 3-(2-methoxycarbonyl-2-propenyl)indoles in which [beta]-OAc functional group was used for the regeneration of Pd(II) species is reported. It was found that for N-protected indoles the reaction proceeded smoothly in the presence of 5 mol % of Pd[(acac).sub.2] and 10 mol % of PP[h.sub.3] at 80 degree Celsius in HOAc, while for N-unprotected indoles, the reaction was carried out by using 5 mol % of Pd[(dba).sub.2] or 2.5 mol % of P[d.sub.2][(dba).sub.3]-CHC[l.sub.3] with 10 mol % of 2,2'-bipyridine as the catalyst in toluene.