Convenient Deoxygenation of Aromatic Ketones by Silica-Supported Chitosan Schiff Base Palladium Catalyst

Hydrogen-Bonding-Mediated Selective Hydrogenation of Aromatic Ketones over Pd/C in Ionic Liquids at Room Temperature

“…1,15−20 Although great progress has been achieved, selective reduction of aromatic ketones without benzene ring hydrogenation over Pd/C is very interesting for accessing aromatic alcohols or alkanes, but it still remains challenging, especially under mild conditions. 5,6 Ionic liquids (ILs) have emerged as a kind of molten salt composed of organic cations and organic/inorganic anions, which can be endowed with specific functions via designing the organic cations and/or anions, thus showing wide applications in many areas. 21−24 In particular, the presence of multiple interactions in IL-based systems, such as electrostatic interaction, van der Waals interaction, and π−π stack interaction, hydrophobic/hydrophilic force and hydrogen bonding (H-bonding), and basicity/acidity provide ILs with multiple roles in chemical reactions.…”

“…The reduction of aromatic ketones with hydrosilanes or hydrogen or alcohols has been widely investigated, which can produce various chemicals, including aromatic and saturated alcohols/alkanes depending on the catalysts and reaction conditions (Scheme ). − To date, concerted efforts have been attempted by combining transition metals involving Rh, Ru, Pd, and Co with strong Brønsted/Lewis acids, and much progress has been achieved. For example, using polymethylhydrosiloxane as the reductant Pd/C can catalyze the reduction of aromatic ketones to alkanes in phenyl chloride (PhCl) at room temperature (Scheme a) .…”

“…For example, using polymethylhydrosiloxane as the reductant Pd/C can catalyze the reduction of aromatic ketones to alkanes in phenyl chloride (PhCl) at room temperature (Scheme a) . The Ru, Co, Mn, and Fe complexes combined with acids or bases can realize selective hydrogenation of aromatic ketones either to aryl alcohols or alkanes at high temperatures. ,− Although great progress has been achieved, selective reduction of aromatic ketones without benzene ring hydrogenation over Pd/C is very interesting for accessing aromatic alcohols or alkanes, but it still remains challenging, especially under mild conditions. , …”

Efficient and Clean Catalytic Hydrogenolysis of Aromatic Ketones by Silica Supported Schiff Base Modify Chitosan-Palladium Catalyst

“…Finally, the silica supported Schiff base modify chitosan-palladium (SiO 2 -CS-Schiff base-Pd) was prepared according to the method of reported in literatures [18,19,23]. The SiO 2 -CS Schiff-base and PdCl 2 were weighed in 10:1 mass ratio and were added in ethanol solvent.…”

“…In the presence of active amino group, CS also exhibits the possibility of chemical modifications, including the preparation of Schiff bases by reaction with aldehydes and ketones [21][22][23]. Recently, we has prepared a silica supported Schiff base modified CS-Pd catalyst and found that it exhibited good catalytic activity in the hydrogenaolysis of 1-tetralone.…”