Table 2. Optimization of [Pd]-Catalyzed Annulation.

entrya	catalyst	ligand	base	yieldc
9	Pd(OAc)2	dppf	K3PO4	65%
10	PdCl2	dppf	K3PO4	16%
11	PdO	dppf	K3PO4	20%
12	Pd(OAc)2	Xantphos	K3PO4	33%
13b	Pd(OAc)2	dppf	K3PO4	42%
14	Pd(OAc)2	dppf	Cs2CO3	72%
15	Pd(OAc)2	dppf	K2CO3	81%
16	PdCl2(PPh3)2		K3PO4	n.dd
17	Pd(dppf)Cl2		K3PO4	34%
18	[(C6H5)3P]2Pd(CH2C6H5)Cl		K3PO4	trace
19	PdCl2·(CH3CN)2		K3PO4	trace

^aReaction conditions: 10a (0.5 mmol), catalyst (5 mol %), ligand (10 mol %), base (1 mmol), 1,4 dioxane (5 mL), reflux, overnight.

^bMicrowave, 120 °C, 30 min.

^cIsolated yields.

^dNot detected.