Direct coupling reaction between alcohols and silyl compounds: Enhancement of lewis acidity of Me3SiBr using InCl3

摘要

The combination of InCl3 and Me3SiBr provided an enhanced Lewis acid system that can be used to promote a wide range of direct coupling reactions between alcohols and silyl nucleophiles in non-halogenated solvents, such as hexane or MeCN. The enhanced Lewis acidity of this system was measured by the C-13 NMR in terms of the coordination to an alcohol. Moreover, the interaction between Me3SiBr and the In(III) species was revealed by Si-29 NMR spectral analysis. Highly chemoselective allylations toward a hydroxyl moiety over ketone and acetoxy ones have been demonstrated.