Three-component,four-centered,one-pot synthesis of 1-(arylethynyl)-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indole derivatives

An efficient three component, four-centered A3 coupling strategy has been developed for the synthesis of a novel series of 1-arylethynyl-tetrahydro-β-carboline derivatives in good yields with high selectivity. This method is also useful for the preparation of 1-arylethynyl tetrahydroisoquinolines, which can be used for the synthesis of biologically active molecules such as homolaudanosine, dysoxyline, methopoline and almorexant. The use of a readily available ZnCl₂/Et₃N reagent system makes this method simple, convenient and practical.