Regioselective synthesis of tetrahydroquinolines via syn- and anti-nucleopalladation-initiated cascade processes

摘要: Palladium(II)-catalyzed regioselective syn-chloropalladation and anti-acetoxypalladation-initiated cascade processes were developed for the synthesis of functionalized tetrahydroquinolines. A series N-propargyl arylamines tethered with an α,β-unsaturated carbonyl scaffold underwent atom economical reactions to deliver chloro- acetoxy-substituted tetrahydroquinolines bearing exocyclic double bond in high yields. mechanism is proposed these involving a sequential or anti-acetoxypalladation alkynes followed by intramolecular olefin insertion (6-exo-trig) protonolysis steps. The reaction was completely terminal aryl/alkyl group propargyl moiety dictated regiochemistry initial nucleopalladation. role bidentate nitrogen ligand crucial trigger acetoxypalladation-initiated sequence contrast chloropalladation-initiated process.