Thermal isomerization of 1,2-diadamantoyltetrakis(trimethylsilyl)disilane via a 2,3-disilabutadiene intermediate

Heating a benzene solution of 1,2-diadamantoyltetrakis(trimethylsilyl)disilane (1a) at 120 °C gave an isomerization product, 3,4-diadamantyl-2,2-bis(trimethylsiloxy)-1,1-bis(trimethylsilyl)-1,2-disilacyclobutene (2), in 24% yield. Similar treatment of 1a in the presence of an excess of methanol at 120 °C afforded a methanol adduct in 39% yield. A mechanistic interpretation including a 2,3-disiladiene intermediate is described for the formation of 2.