The Reaction of Group 14 Dimetallenes with Alkenes: Electron-Poor Alkenes

Abstract

The addition reactions of tetramesitylgermasilene with methyl vinyl ketone (MVK), crotonaldehyde, and acrylonitrile were studied. When tetramesitylgermasilene was allowed to react with MVK, [2 + 4] cycloaddition and nonregioselective carbonyl [2 + 2] cycloaddition products were isolated. When tetramesitylgermasilene was allowed to react with crotonaldehyde, the carbonyl [2 + 2] adduct was produced exclusively. The regiochemistry was not determined. The addition of acrylonitrile to tetramesitylgermasilene yielded a germasilacyclobutane, which is the formal [2 + 2] cycloadduct between the germasilene and the C−C double bond of acrylonitrile. Tetramesityldisilene was also found to yield a formal [2 + 2] adduct with acrylonitrile. However, tetramesityldigermene rearranges to a germylgermylene at a faster rate than acrylonitrile addition.