Oxidative Pictet-Spengler cyclisations through acceptorless iridium-catalysed dehydrogenation of tertiary amines

Syntheses of Tetracyclic Indoline Derivatives Via Gold(I)-Catalyzed Hydroamination/Cycloisomerization Cascade of 2-Ethynyltryptamides

“…Tetrahydro-β-carboline alkaloids are naturally occurring indole alkaloids and have drawn much attention for their extensive and unique biological activity, of which indolizino­[8,7- b ]­indole (Figure , labeled in blue) and indolo­[2,3- a ]-quinolizine (Figure , labeled in red) are two representative structures . At present, some natural products containing such skeletons have been used as drugs in clinic or lead compounds in medicinal chemistry, and the total synthesis of such natural products has attracted research interest of chemists . The main strategies for the syntheses of these key skeletons are N -acyl-iminium ion or iminium ion cyclizations, , including Pictet–Spengler reaction, , Bischler–Napieralski reaction, enzyme-mediated oxidation, , transition metal-catalyzed dehydrogenation , etc.…”