A facile and efficient method to introduce alkyne groups to the C-1 position of biologically interesting 1,2,3,4-tetrahydroisoquinolines via direct C-H-functionalization is reported. Various alkynylated N-substituted 1,2,3,4-tetrahydroisoquinolines could be obtained by using copper(I)-chloride as catalyst, alkynoic acids as alkyne source and t-BuOOH as oxidant, in a one-pot two-step decarboxylation-alkynylation reaction in moderate to high yields. Furthermore, a one-pot protocol of a three-step decarboxylation-alkynylation-1,3-dipolar cycloaddition reaction leading to 1-triazolyl-tetrahydroisoquinolines was developed, a hitherto unknown reaction cascade. (C) 2016 Elsevier B.V. All rights reserved.