Synthesis of (alk-1-ynyl)cyclopropenium salts via the reaction of (alk-1-ynyl)chlorocarbenes with diphenylacetylene

1-(Alk-1-ynyl)-2,3-diphenylcyclopropenium perchlorates 7 have been prepared via the generation of (alk-1-ynyl)chlorocarbenes 3 from 1,1-dichloroalk-2-ynes 1 or 3-bromo-1,1,1-trichloro-3-phenylpropane 2 by the interaction with Bu^tOK in the presence of tolan followed by the treatment of the reaction mixture with perchloric acid, whereas the treatment of the reaction mixture with HBr resulted in (2-bromoalk-1-enyl)cyclopropenium bromides 9