title: Dual hard/soft gold catalysis: intermolecular Friedel-Crafts-type α-amidoalkylation/alkyne hydroarylation sequences by N-acyliminium ion chemistry.
abstract: Gold catalysts have been applied in cascade-type reactions for the synthesis of different nitrogen-based compounds. The reactions likely proceed by a new gold-catalyzed cascade intermolecular α-amidoalkylation/intramolecular carbocyclization cascade process by unifying both the σ- and π-Lewis acid properties of the gold salts. In the first part of this report we show that the σ-Lewis acidity of gold(I) and gold(III) could be exploited to efficiently catalyze the nucleophilic substitution of various alkoxy- and acetoxylactams. The reaction was found to be applicable to a wide range of cyclic N-acyliminium ion precursors and various nucleophiles, including allyltrimethylsilane, silyl enol ethers, arenes, and active methylene derivatives. As a logical progression of this study, a combined hard/soft binary catalytic gold system was then used to implement an unprecedented tandem intermolecular Friedel-Crafts amidoalkylation/intramolecular hydroarylation sequence allowing an expedient access to new, complex, fused polyheterocyclic structures from trivial materials.
authors.affiliation: URCOM, EA,CNRS, FR, Université du Havre, Le Havre, France.
authors.forename: Liliana
authors.initials: L
authors.lastname: Boiaryna
authors.forename: Mohamed Kamal
authors.initials: MK
authors.lastname: El Mkaddem
authors.forename: Catherine
authors.initials: C
authors.lastname: Taillier
authors.forename: Vincent
authors.initials: V
authors.lastname: Dalla
authors.forename: Mohamed
authors.initials: M
authors.lastname: Othman