A novel dibutyltin oxide-catalyzed transesterification reaction between acetylated maritime pine sapwood (Pinus pinaster Soland) and methyltrimethoxysilane (MTMS) was studied. The transesterification exchange between the acetyl moities and MTMS was confirmed by weight percent gain calculations, Fourier-transform infrared spectroscopy, as well as solid state C-13 and Si-29 cross-polarization with magic-angle spinning nuclear magnetic resonance spectroscopy. The silicon atoms in the MTMS-transesterifted wood were found to exist in the form of more or less condensed structures, concurrently formed by condensation between neighboring Si(OMe)(3) groups. An increase in the acetyl/MTMS exchange rate was also noted when the catalyst amount, temperature, or reaction time were increased. (c) 2007 Wiley Periodicals, Inc.