Silica-Supported Silver Nitrate as a Highly Active Dearomatizing Spirocyclization Catalyst: Synergistic Alkyne Activation by Silver Nanoparticles and Silica.
Silica-supported AgNO3(AgNO3-SiO2) catalyzes the dearomatizing spirocyclization of alkyne-tethered aromatics far more effectively than the analogous unsupported reagent; in many cases, reactions which fail using unsupported AgNO3proceed effectively with AgNO3-SiO2. Mechanistic studies indicate that this is a consequence of silver nanoparticle formation on the silica surface combined with a synergistic effect caused by the silica support itself. The remarkable ease with which the reagent can be prepared and used is likely to be of much synthetic importance, in particular, by making nanoparticle catalysis more accessible to non-specialists.
University of York, York, YO10 5DD, UK.
Aimee K
AK
Clarke
University of York, York, YO10 5DD, UK.
Michael J
MJ
James
University of York, York, YO10 5DD, UK.
Peter
P
O'Brien
University of York, York, YO10 5DD, UK. richard.taylor@york.ac.uk.
Richard J K
RJ
Taylor
University of York, York, YO10 5DD, UK. william.unsworth@york.ac.uk.
William P
WP
Unsworth
dearomatization; flow chemistry; heterogeneous catalysis; silver nanoparticles; spirocycles