Triphenylgermane adds easily to acetylenes in the presence of Et3B to give (E)- or (Z)-alkenyltriphenylgermanes, respectively, under excellent control of regio- and stereoselectivities.
Treatment of 1-dodecyne with triphenylgermane in the presence of catalytic amounts of tributylmanganate at 25 °C provided 1-triphenylgermyl-1-dodecene in good yield. The reaction proceeded in a radical pathway and treatment of diene afforded the corresponding radical cyclization product.