Gold‐Catalyzed Synthesis of Quinolines from Propargyl Silyl Ethers and Anthranils through the Umpolung of a Gold Carbene Carbon

Abstract

A gold-catalyzed cascade annulation of propargylic silyl ethers with anthranils proceeds through a sequential ring opening/1,2-H-shift/protodeauration/Mukaiyama aldol cyclization. This method offers a regiospecific and modular access to 2-aminoquinolines and other quinoline derivatives under mild conditions and with a broad functional-group tolerance. The conversion is possible on a gram scale, which underlines the synthetic practicability of this methodology. The versatility of the obtained scaffold has been demonstrated by useful postfunctionalization.

Gold-catalyzed heterocyclic syntheses through α-imino gold carbene complexes as intermediates

“…This methodology has been developed in our research group and implies an initial gold catalyzed intramolecular 5-endodig cyclization of 1H-propargyl benzotriazoles 244, giving rise to the formation of dipolar 1,2,3-triazapentalenes 245 (Scheme 60). This reaction, in addition to the examples reported by Hashmi et al 61,67,68 and R.-S. Liu et al 63,64 using anthranils and isoxazoles, respectively, remains, to the best of our knowledge, as the sole intermolecular examples of this type of processes that do not require the participation of highly polarized alkynes.…”

Recent Progress on Cyclic Nitrenoid Precursors in Transition‐Metal‐Catalyzed Nitrene‐Transfer Reactions

“…silyl ethers leading to quinolines (Scheme 88). [93] Key to this report was a1 ,2-H migration of the resultingg old-carbenoid complex. The resulting N-aryl-a,b-unsaturated imines underwent Mukaiyama aldol condensation to give 3-acylquinolines.…”

Gold(III)‐Catalyzed Site‐Selective and Divergent Synthesis of 2‐Aminopyrroles and Quinoline‐Based Polyazaheterocycles

“…In line with this principle, various nitrenoid equivalents have been realized for intermolecular nitrene‐transfer processes to ynamides, generating highly electrophilic gold carbene intermediates A . Typically, a nucleophilic functionality tethered on the nitrene‐transfer reagent traps the gold carbene, leading to formal [3+2] cycloadducts (Scheme , top); or a new C−C double bond is formed via a 1,2‐hydride shift if the α‐hydrogens exist (middle) ,. The site‐selective trapping by the R 1 substituent at the ynamide is more challenging, as the competing nucleophilic site Z can induce undesired side reactions.…”