Addition of a cyclopropyl alkyne to tetramesityldisilene: Evidence for a biradical intermediate and formation of a stable 1,2-disilacyclohepta-3,4-diene

The intermediate formed during the addition of an alkyne to tetramesityldisilene has been determined to be a biradical by the use of a newly developed mechanistic probe, designed to discriminate among vinyl radicals, cations, and anions.