One-Pot Synthesis of 2-(Alkylsulfanyl)quinolines from Aryl Isothiocyanates and Allenes or Alkynes

In this work, a conceptually novel approach to diversely substituted 2-(alkylsulfanyl)quinolines is described. The approach includes the assembly of the target molecules from allenic or acetylenic carbanions, aromatic isothiocyanates, and alkylating agents. The process proceeds in a single synthetic operation via the formation and 6 pi-electrocyclization of N-aryl-1-aza-1,3,4-trienes, R2R3C=C=C(R1)C(SAlk)=NAr, with the participation of the carbon-carbon double bond of the phenyl group and the azadiene fragment of the azatrienic system. A simple and convenient approach to new families of variously substituted 2-(alkylsulfanyl)quinolines, which are difficult to access via traditional methods for quinolines synthesis, is reported. Allenes or alkynes, aryl isothiocyanates, and alkylating agents have been shown to be readily available building blocks for the one-pot assembly of functionalized quinoline systems. image