Initially, the direct palladium-catalyzed vinylation of 1 was investigated using the combination of Pd(OAc) 2 pre-catalyst, Cs 2 CO 3 as the base and dioxane as the solvent, which proved effective in the analogous direct (hetero)arylation of 1 with aryl halides 6 (Scheme 1 and Table 1). The performance of the ligand in the direct vinylation of 1 with 1-bromo-2-methylpropene carried out in dioxane in a sealed tube at 110 °C for 18 h is summarized in Table 1 (runs 1–10).
