Abstract
A dehydrative cross-coupling of 1-phenylethanol catalysed by sugar derived, in situ
formed palladium(0) nanoparticles under acidic conditions is realised. The acidic
conditions allow for use of alcohols as a feedstock in metal-mediated coupling reactions
via their in situ dehydration and subsequent cross-coupling. Extensive analysis of
the size and morphology of the palladium nanoparticles formed in situ showed that
the zero-valent metal was surrounded by hydrophilic hydroxyl groups. EDX-TEM imaging
studies using a prototype silicon drift detector provided insight into the problematic
role of molecular oxygen in the system. This increased understanding of the catalyst
deactivation allowed for the development of the cross-coupling methodology. A 250-12,000
fold increase in molar efficiency was observed when compared to related two-step protocols
that use alternative feedstocks for the palladium-mediated synthesis of stilbenes.
This work opens up a new research area in which the active catalyst is formed, stabilised
and regenerated by a renewable sugar.
Key words
glucose - nanoparticles - catalysis - dehydrative heck - palladium