Table 1. Optimization of the Cu-transannulation reaction conditions ^a .

Entry	Catalyst, mol%	T (°C)	Yield b
1	CuCl, 15%	100	N.R.
2	CuOTf·0.5C6H6, 15%	100	38%
3	Cu(OTf)2, 15%	100	25%
4	Cu(MeCN)4PF6, 15%	100	50%
5 c	Cu(MeCN)4PF6, 15%	120	96%
6 c	Cu(MeCN)4PF6, 15%	130	99%
7 d , e	Cu(MeCN)4PF6, 15%	130	99%
8	No catalyst	100	N.R.
9	Rh2(hfb)4, 1%	100	N.R. f

^aTriazole (1 equiv.), alkyne (3 equiv.), Cu cat. (15 mol%), toluene (1 M) in a Wheaton V-vial capped with a Mininert syringe valve.

^bGC/MS yields are given.

^c1.2 equiv. of alkyne was used.

^dIn air with 1.2 equiv. of alkyne.

^eLower catalyst loading led to decreased reaction yields.11

^fPolymerization of the alkyne was observed; hfb = heptafluorobutyrate.