Task-specific ionic liquid-catalyzed efficient couplings of indoles with 1,3-dicarbonyl compounds: an efficient synthesis of 3-alkenylated indoles

Direct alkenylation of indoles at the 3-position with 1,3-dicarbonyl compounds under Brّnsted acidic ionic liquid catalysis has been developed. The yields were excellent, and the catalyst can be reused at least six times without noticeable loss of catalytic activity.