Reaction of 9,10-dimethyl-9,10-dihydro-9,10-disilaanthracene with alkyne in the presence of palladium

Reaction of 9,10-dimethyl-9,10-dihydro-9,10-disilaanthracene (1) with alkynes in the presence of palladium catalyst was examined. The formal Diels–Alder adduct was isolated from the reaction mixture, indicating the possibility of the intermediacy of 9,10-disilaanthracene, a novel silaaromatic compound. It was found that the [4+2] adduct was obtained only from the cis isomer of the 9,10-dihydro-9,10-disilaanthracene.