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Nonhydrolytic Synthesis of Branched Alkoxysiloxane Oligomers Si[OSiH(OR)2]4 (R=Me, Et)


  • We are grateful to Dr. T. Shibue (MCCL, Waseda University) for help with the 29Si–1H HMBC and high-resolution EI-MS measurements, and also to S. Inoue (MCCL, Waseda University) for the high-resolution FAB-MS measurement of Si(OCHPh2)4. This work was supported in part by a Grant-in-Aid for Scientific Research (no. 20245044) and the Global COE program “Practical Chemical Wisdom” from MEXT (Japan). R.W. acknowledges a Waseda University Grant for Special Research Projects (2009A-899). K.K. is grateful for financial support provided through a Grant-in-Aid for JSPS Fellows from MEXT, and support by the Elements Science and Technology Project “Functional Designs of Silicon-Oxygen-Based Compounds by Precise Synthetic Strategies” from MEXT (Japan).


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Beyond silanol: A branched siloxane oligomer bearing terminal dialkoxysilyl groups was nonhydrolytically synthesized by direct alkoxysilylation of a tetraalkoxysilane with a chlorodialkoxysilane in the presence of the Lewis acid BiCl3 (see scheme). The reaction proceeds without the formation of intermediate silanol groups, and provides a selective route for siloxane-based oligomers.