Thiol-isocyanate Click Reaction for Rapid and Efficient Generation of a Library of Organofunctional Silanes

Herein, we report a simple, very fast, and efficient method for the synthesis of a library of organofunctional alkoxysilanes based on an amine-catalyzed thiol-isocyanate click reaction. At first, systematic studies were carried out to select the most active catalyst and its concentration for the model reaction involving 3-isocyanatopropyltriethoxysilane (ICPTES) and 1-octanethiol. Six tertiary amines were studied using an in situ FT-IR technique. After an effective catalytic system was selected, a set of alkoxysilanes containing various functional groups were synthesized. In addition, new thiols and thioacetates (sequentially reduced to thiols) were obtained as a result of the thiol–ene reaction. Two synthetic routes were applied to obtain alkoxysilanes, the reaction between ICPTES and functional-group-containing thiols or between 3-mercaptopropyltriethoxysilane (MPTES) and functional-group-containing isocyanates. The developed procedure permitted the synthesis of 13 new organosilicon compounds. The silanes obtained contain various functional groups, i.e. long alkyl or fluoroalkyl chain, phenyl, trisiloxane, naphthyl, trisilylamine, or polyether.