Metalation of olefinic positions in norbornadiene: enhancement and attenuation of kinetic CH-acidities by a neighboring enesilane moiety

When treated with BuLi in the presence of Na or K tert-butoxide, 2-(trimethylsilyl)- and 2-(triethylsilyl)norbornadiene undergo H/metal-exchange mainly at the 5-position. The latter position is slightly activated relative to unsubstituted norbornadiene while the 2 other olefinic positions prove to be a quite inert. Two side reactions are obsd.: the metalation of Si-attached Me groups and the replacement of the entire trialkylsilyl group by a metal atom.