Addition of Organometallic Reagents to a Stable Silene and Germene

A variety of alkyllithium (R = Me, Bu, t-Bu) reagents and potassium tert-butoxide were added to the highly reactive silene Mes2Si=CHCH2t-Bu (1) and the germene Mes2Ge=CHCH2t-Bu (4) in diethyl ether. 1,2-Addition products were obtained regioselectively and in good yield after treatment with a weak acid with no evidence for any rearrangement products and no polymerization observed. The reactivity of the silene 1 and germene 4 toward organometallic reagents is compared to previous studies of analogous silenes and germenes. (Chemical Equation Presented).