The versatile reaction chemistry of penta-coordinated silanes of type [C6H4CH2N (CH3) 2 2](H2C CH)(CH3) SiH (1a) and [C6H4CH2N (CH3) 2 2](H2C CH) SiH2 (1b) with different substrates is described. The reaction behavior along with the structure and bonding of the compounds obtained is compared with tetravalent silicon molecules. Hypervalent 1a and 1b react, without added catalysts, with alcohols, water and benzoylic acid to produce ...