Silylation of cellulose regiocontrolled by bulky reagents and dispersity in the reaction media

Publisher Website
Google Scholar
Abstract
Reaction of cellulose (1) with the bulky thexyldimethylchlorosilane (TDMSCl) leads to regioselectively functionalized silyl celluloses with degree of substitution (DS) up to 2. Uniform 6‐O‐thexyldimethylsilyl cellulose (2) was obtained in ammonia‐saturated aprotic dipolar media, which was unexpected in a heterogeneous reaction. On the contrary, the 6‐O‐selectivity is low under homogeneous conditions in a N,N‐dimethylacetamide (DMA)/LiCl solution, and with an excess of TDMSCl 2,3‐di‐O‐thexyldimethylsilyl cellulose (3) can be synthesized. The polymer structures were characterized by two dimensional NMR spectroscopy after subsequent methylation (polymers 4 and 5), desilylation (polymers 6 and 7) and acetylation (polymers 8 and 9) as well as by HPLC after chain degradation of 4 and 5 to the complementary methyl glucoses.
Funding Information
  • Deutsche Forschungsgemeinschaft