The value of 1-(benzenesulfonyl) pyrrole-3-carboxaldehyde as a synthon in heterocyclic chemistry, especially for the preparation of highly functionalized indoles,'has impelled the search for methods of preparation based on direct formylation? However, although 1- (benzenesulfonyl) pyrrole displays an unusual proclivity toward P-substitution in aluminum chloride mediated Friedel-Crafts acylations? all previous attempts to introduce one carbon ...