3-Bromo-N-methylpyridinium iodide 3a was treated with tributylvinylstannane in the presence of 5 mmol% Pd(PPh 3 ) 4 in DMF at room temperature with 10 mmol% copper(I) iodide as co-catalyst (Method A). [10] In this case, however, only traces of the desired derivative were obtained. Repeated attempts at 80 ºC gave the 3-vinyl derivative 4a in only 20% yield. In contrast, coupling of 3a with donor [11] units such as phenylethynyl-, phenyl-, 2-thienyl-, 2- ...
