Addition of Free Me2Ge: to Alkenes and Alkynes on Glass Surfaces in the Presence of Water

Traces of water on glass surfaces (even after heating) can decisively influence the course of a reaction. This is shown by the reactions of Me2Ge: with alkenes such as acrylonitrile and alkynes such as phenylacetylene in “anhydrous” medium. These reactions afforded poor yields of 1 and 2, respectively. On the other hand, reaction in the presence of water and silica gel gave 1 and 2 in nearly quantitative yield; the presence of water alone did not increase the yield. These findings indicate that acidic H atoms, formed on the silica surface, are essential for the reaction of the expected products with water.