Table 2. Optimization of Pd-Catalyzed Arylation of CsOH at Room Temperature^a.

entry	H2O (equiv)	solvent	conv. (%)b	yield of 4 (%)b
1	1c	1,4-dioxane	18	8
2	10	1,4-dioxane	100	96
3	20	1,4-dioxane	93	89
4	30	1,4-dioxane	57	53
5	1c	THF	28	20
6	10	THF	60	51

^aReaction conditions: 1-bromo-2,4-dimethylbenzene (0.25 mmol), CsOH (0.75 mmol), H₂O (1–30 equiv), 1 (2 mol %), L5 (2 mol %), solvent (0.5 mL), rt, 20 h; trace amounts of anisole and biaryl ether were detected by GCMS.

^bDetermined by GC.

^cThe water was from CsOH·H₂O; no extra water was added.