Recently, we have described that Hg(OTf)2 and it's tetramethylurea (TMU) complex show highly efficient catalytic activity for the hydration of terminal alkynes to give methylketones, hydroxylative 1,6-enyne cyclization leading to exomethylene five-membered ring products, and arylalkyne cyclization leading dihydronaphthalene derivatives in excellent yield. We would like to discribe herein our recent observation dealing with Hg(OTf)2-catalyzed cyclization of yne-ene-aryl substrate to give tricarbocyclic product. This is the first example of metal salt-catalyzed biomimetic tandem cyclization. We also disclose Hg(OTf)2-catalyzed furan systhesis, cyclic enolether synthesis, ω-methylene-ω-lactone synthesis, novel glycosyration reaction, indol sysnthesis, hydroxylative enone synthsis from propargyl acetates, and inter molecular condensation of alkyne with carbon nucleophiles.
