Table 1.

Optimization of reaction conditions for seven-membered lactone synthesis.

Entrya	[Pd], x mol%	Ligand, 7.5 mol%	Base, z equiv.	Yield/%b
1	Pd2(dba)3•CHCl3, 2.5	dppm	K3PO4, 4.0	5
2	Pd2(dba)3•CHCl3, 2.5	dppe	K3PO4, 4.0	52
3	Pd2(dba)3•CHCl3, 2.5	dppp	K3PO4, 4.0	67
4	Pd2(dba)3•CHCl3, 2.5	dppb	K3PO4, 4.0	57
5	Pd2(dba)3•CHCl3, 2.5	dpppe	K3PO4, 4.0	35
6	Pd2(dba)3•CHCl3, 2.5	dppf	K3PO4, 4.0	49
7	Pd2(dba)3•CHCl3, 2.5	DPEphos	K3PO4, 4.0	5
8	Pd2(dba)3•CHCl3, 2.5	Xantphos	K3PO4, 4.0	77(76)c
9	Pd2(dba)3•CHCl3, 2.5	Xantphos	K3PO4, 4.0	77d
10	Pd2(dba)3•CHCl3, 2.5	Xantphos	K2CO3, 4.0	70(74)c
11	Pd(OAc)2, 5	Xantphos	K2CO3, 3.0	76(76)c,e
12	PdCl2, 5	Xantphos	K2CO3, 3.0	73e
13	[(η-C3H6)PdCl]2, 2.5	Xantphos	K2CO3, 3.0	75e
14	Pd(OAc)2, 5	Xantphos	K2CO3, 3.0	64f

^aReaction condition: 1a (0.2 mmol), 2a (0.4 mmol), [Pd] (5 mol%), Ligand (7.5 mol%), base (z equiv.) in THF (2.0 mL), stirring under atmosphere of Argon at 80 °C for 24 h

^bNMR yields were determined using mesitylene as internal standard

^cIsolated yield

^dDioxane

^e12 h

^f1b was employed instead of 1a