Gold(I)‐Catalysed Hydroarylation of Lactam‐Derived Enynes as an Entry to Tetrahydrobenzo[g]quinolines

Abstract

The gold(I)‐catalysed cyclization of N‐tosyl‐protected 5‐benzyl‐6‐((trimethylsilyl)ethynyl)‐1,2,3,4‐tetrahydropyridines, prepared by the Sonogashira coupling of lactam‐derived enol triflates, provides tetrahydrobenzo[g]quinolines whose skeleton represents a recurrent motif in natural compounds. The Au(I)‐catalysed reaction is carried out with (C6F5)3PAuCl/AgNTf2 as the catalyst system and proceeds via a 6‐exo‐dig cyclization to form an exocyclic double bond, which eventually isomerises to the aromatic tetrahydrobenzo[g]quinoline. The mode of cyclization is discussed and supported by DFT calculations.

Advances in gold catalyzed synthesis of quinoid heteroaryls

“…In another study, 100 protodeauration to form exo intermediate C, which aromatizes rapidly to yield the nal product 2l. 101…”

Triflamides and Triflimides: Synthesis and Applications

“…The combination of AgNTf 2 33 and the AuCl-based ligand was also successfully used in the cycloisomerization of 1,6-enyne to 3-azabicyclo[4.1.0]heptene [66], as well as in the asymmetric synthesis of fused bicyclic N,Oand O,O-acetals [67]. The (C 6 F 5 ) 3 PAuCl/AgNTf 2 catalyzed cyclization of N-tosyl-protected 5-benzyl-6-((trimethylsilyl)ethynyl)-1,2,3,4-tetrahydropyridines obtained by the Sonogashira reaction in the presence of enol triflate lactam derivatives gives tetrahydrobenzo[g]quinolines, the skeletal framework of which is a recurring motif in natural products [68].…”

An all-in-one approach for synthesis and functionalization of nano colloidal gold with acetylacetone

“…All the calculations of ground states were performed with the density functional theory (DFT) using the Gaussian 16 software package [40]. Geometry optimization was conducted at the ωB97XD/def2-SVP [41] level of theory followed by frequency calculations to verify that the stationary points obtained were the local energy minimal, and to evaluate the zero-point vibrational energies and thermal corrections at 298 K. The energies of the species after optimization were calculated at the ωB97XD/def2-TZVP [42] level of theory. The excited states were computed using time-dependent density functional theory (TD-DFT).…”