or a heteroaryltrialkylstannane, in a solvent, such as toluene or tetrahydrofuran or n-butanol or 1,4-dioxane or 1,2-dimethoxyethane or a mixture of solvents, such as tetrahydrofuran and methanol, at an elevated temperature, such as 200??? C. or 120??? C. or 80??? C. achieved by either conventional or microwave heating, optionally in a sealed vessel to allow heating above the normal boiling point