Table 1. Optimization of the reaction conditions ^a .

Entry	Ligand	Base	Yield b (%)
1	dppp	Cs2CO3	44
2	dppe	Cs2CO3	19
3	dppf	Cs2CO3	85 (83)
4	dppf	K3PO4	51
5	dppf	KOtBu	80
6	dppf	DBU	27
7 c	dppf	Cs2CO3	73
8 d	dppf	Cs2CO3	72
9	No	Cs2CO3	13
10	dppf	No	31
11 e	dppf	Cs2CO3	78
12 f	dppf	Cs2CO3	N.D.
13 g	dppf	Cs2CO3	N.D.

^aReaction conditions: 1a (0.4 mmol).

^bYields were determined by crude ¹H NMR using dibromomethane as an internal standard, and the isolated yields are given in parentheses.

^cBase (0.4 mmol).

^dBase (0.6 mmol).

^eNo CsF.

^fNo [Ru(p-cymene)Cl₂]₂.

^gN₂ instead of CO₂. DBU = 1,8-diazabicyclo[5.4.0]undec-7-ene. N.D. = not detected.