Synthesis of Indoles and Benzofurans Using a Graphene Oxide-Grafted Aminobisphosphine-PdII Complex

Palladium complexes with an annellated mesoionic carbene (MIC) ligand: catalytic sequential Sonogashira coupling/cyclization reaction for one-pot synthesis of benzofuran, indole, isocoumarin and isoquinolone derivatives

A Pd(ii) complex containing a mesoionic carbene and phosphine ligands is an efficient catalyst for tandem coupling/cyclization reaction.

Potassium tert-Butoxide-Mediated Condensation Cascade Reaction: Transition Metal-Free Synthesis of Multisubstituted Aryl Indoles and Benzofurans

An efficient and facile method to synthesize valuable disubstituted 2-aryl indoles and benzofurans in good yields has been demonstrated, based on a tert-butoxide-mediated condensation reaction involving a vinyl sulfoxide intermediate. Products are obtained from N- or O-benzyl benzaldehydes using dimethyl sulfoxide as a carbon source. The methodology features a wide functional group tolerance and transition metal-free environment. Preliminary mechanistic studies suggest that the reaction involves a tandem aldol reaction/Michael addition/dehydrosulfenylation/isomerization sequence through an ionic protocol.

Facile synthesis of 2-substituted benzo[b]furans and indoles by copper-catalyzed intramolecular cyclization of 2-alkynyl phenols and tosylanilines

A catalytic amount of CuCl and Cs₂CO₃ was employed to synthesize a variety of 2-substituted benzo[b]furans and indoles by an intramolecular cyclization of 2-alkynyl phenols and tosylanilines. This protocol features mild conditions, high yields and broad substrate scope, which makes it a practical method for the synthesis of 2-substituted benzo[b]furans and indoles.

A facile and inexpensive copper-catalyzed method was developed for the synthesis of 2-substituted benzo[b]furans and indoles.