Microwave-assisted solid-phase organic synthesis (MASPOS) as a key step for an indole library construction

graphics Microwave-assisted solid-phase organic synthesis (MASPOS) has been demonstrated to significantly facilitate the Cu(II)- or Pd(II)-mediated ring closure of the resin-bound 2-alkynylanilides. Under microwave irradiation at 200 degreesC [for Cu(OAc)(2), NMP] or 160 degreesC [for Pd(MeCN)(2)Cl-2, THF] for 10 min, 1-acyl-2-alkyl-5-arenesulfamoylindoles were obtained, after cleavage from the resin, in 95-99% purities and in 65-82% overall yields via a 5-step synthetic sequence.