Leaving Group Effects on the Selectivity of the Silylation of Alcohols: The Reactivity-Selectivity Principle Revisited

摘要

TBS protection of primary alcohol naphthalen-1-ylmethanol (4a) and secondary alcohol 1-(naphthalen-1-yl)ethanol (4b) has been studied under various reaction conditions. The primary/secondary selectivity is largest in the comparatively slow Lewis base catalyzed silylation in apolar solvents and systematically lower in DMF. Lowest selectivities (and fastest reaction rates) are found for TBS triflate 1b, where only minor effects of solvent polarity or Lewis base catalysis can be observed.