2a (175 mg, 0.59 mmol) and 4-(3-mercapto-phenyl)-tetrahydro-pyran-4-ol (2b, 150 mg, 0.71 mmol) were combined in 1,4-dioxane (6 mL) and degassed with N2 for 10 minutes. iPr2NEt (0.33 mL, 1.8 mmol) was added, followed by Pd2dba3 (14 mg, 0.02 mmol) and 4,5-bis(diphenylphosphino)-9,9-dimethylxanthene (16 mg, 0.03 mmol). The mixture was degassed with N2 for an additional 10 minutes, and then heated to 80° C. for 24 hours. The reaction was cooled to room temperature, concentrated, and purified by silica gel chromatography (0-20% MeOH in EtOAc) to give the desired product, 2c.
