Effect of reaction conditions on coupling of terminal alkyne 1a with 2a^a.

Entry	Catalyst	Base	Solvent	Time (h)	% Yieldb
1	10% Pd/C/CuI	K2CO3	DMF	6	0c
2	10% Pd/C/PPh3/CuI	K2CO3	DMF	6	15d
3	Pd(OAc)2/PPh3/CuI	K2CO3	DMF	6	20d
4	Pd(OAc)2/PPh3/CuI	Et3N	DMF	6	30d
5	Pd(OAc)2/PPh3/CuI	Et3N	EtOH	6	20d
6	Pd(PPh3)2Cl2/CuI	Et3N	EtOH	6	40c
7	Pd(PPh3)2Cl2/CuI	Et3N	Et3N	2	85 c
8	Pd(PPh3)2Cl2/CuI	Et3N	Et3N	6	83c
9	Pd(PPh3)2Cl2	Et3N	Et3N	6	0c
10	CuI	Et3N	Et3N	6	0c

^aReactions were carried out using alkyne 1a (1 mmol), 2a (1.2 mmol), catalyst and base (2.0 mmol) in a solvent (5 mL) under nitrogen at 60 °C.

^bIsolated yield.

^c5 mol% of each catalyst used.

^d5 mol% of each catalyst and 10 mol% of PPh₃ used.