Facile cleavage of Si-C bonds during the sol-gel hydrolysis of aminomethyltrialkoxysilanes - A new method for the methylation of primary amines

The reaction of chloromethyltriethoxysilane with (1R,2R)-bis(methylamino)cyclohexane (1) afforded the corresponding bis-silylated compound 2. The sol-gel hydrolysis of 2 did not give the expected bridged silsesquioxane owing to quantitative Si-C-bond cleavage. Instead, silica and (1R,2R)-bis(dimethylamino)cyclohexane (3) were obtained. This reaction was exploited to propose a new route for the methylation of amines. Such methylation reaction of amines could be extended to other amines and provides a new method for the selective monomethylation of primary amines. ((C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004).