Table 1.

Reaction optimization.^[a]

Entry	Deviations from above	Yield[b] (3 a) [%]
1	–	55
2	1 equiv. 1 a, 3 equiv. 2 a	40
3	Pd source: PdCl2/Pd(TFA)2/Pd2(dba)3	trace/24/16
4	K2CO3 instead of Cs2CO3	trace
5	THF instead of PhH solvent	62
6	10 mol % RuPhos instead of Xantphos	3 a: n.d. 4: 63 %
7	10 mol % Pd(OAc)2, 20 mol % Xantphos, THF solvent	83 (81)[c]
8	cyclohexyl bromide instead of 2 a	trace
9	reaction in the dark	no reaction

[a] Reaction conditions: 0.6 mmol 1 a (3 equiv.), 0.2 mmol 2 a (1 equiv.), 0.4 mmol (2 equiv.) Cs₂CO₃, 5 mol % Pd(OAc)₂, 10 mol % Xantphos were dissolved in 1 mL benzene under argon atmosphere, irradiated with 3 W blue led (470 nm) at room temperature overnight. [b] The yield was determined by ¹H NMR spectroscopy of the crude reaction. The internal standard was CHBr₃. [c] Isolated yield.