Iridium and Ruthenium Catalyzed Syntheses, Hydroborations, and Metathesis Reactions of Alkenyl-Decaboranes

The selective syntheses of new classes
of 6,9-dialkenyl- and 6-alkenyl-decaboranes and 6-alkyl-9-alkenyl-decaboranes
have been achieved via iridium and ruthenium catalyzed decaborane
and 6-alkyl-decaborane alkyne-hydroborations. Reactions employing
[Cp*IrCl2]2 and [RuCl2(p-cymene)]2 precatalysts gave β-E-alkenyl-decaboranes,
while the corresponding reactions with [RuI2(p-cymene)]2 gave the α-alkenyl-decaborane isomers,
with the differences in product selectivity suggesting quite different
mechanistic steps for the catalysts. The alkenyl-decaboranes were
easily converted to other useful derivatives, including coupled-cage
and functionally substituted compounds, via iridium-catalyzed hydroborations
and ruthenium-catalyzed homo and cross olefin-metathesis reactions.