Table 1.
Conditions: 0.1 mmol of 1a, 2.0 equiv of NBS, 10 mol% of Pd(OAc)2, 10 mol% of ligand, 1.5 equiv of PhI(OAc)2, 1.0 mL of DCE, 80 °C, under air, 20 h.
The yield was determined by 1H NMR analysis of the crude product using CH2Br2 as the internal standard.
Optimal conditions: 0.1 mmol of 1a, 1.75 equiv of NBS, 10 mol% of Pd(OAc)2, 10 mol% of ligand L6, 1.5 equiv of PhI(OAc)2, 5.0 equiv of AcOH, 1.0 mL of DCE, 70 °C, under air, 20 h.