Treatment of acetylenes with Ph3SnH or Ph3GeH in the presence of a catalytic amount of Pd(PPh3)4 provides the corresponding alkenyltriphenylstannanes or alkenyltriphenylgermanes in good yields.
Triphenylgermane adds easily to acetylenes in the presence of Et3B to give (E)- or (Z)-alkenyltriphenylgermanes, respectively, under excellent control of regio- and stereoselectivities.
Isomerization of olefins with R3SnH–Et3B (R = Ph or n-Bu) system has been studied. Treatment of (Z)-1-triphenylstannyl-1-octene (1) or (E)-1-triphenylstannyl-1-octene (2) with a catalytic amount of Ph3SnH–Et3B provided an equilibrium mixture of 1/2 = 2/8. Partial isomerization was observed in the reaction of trivial alkenes such as 6-dodecene and 2,2-dimethyl-3-dodecene with R3SnH–Et3B system. Whereas
Treatment of 1-alkenylsulfides or 1-alkenylstannanes with Ph3GeH in the presence of Et3B provides 1-alkenyltriphenylgermanes in good yields. 1-Alkenylstannanes are converted into 1-alkenylsulfides easily with PhSH–Et3B, whereas 1-alkenyltriphenylgermanes are recovered unchanged upon treatment with Ph3SnH–Et3B or PhSH–Et3B.
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.