2129-31-9Relevant articles and documents
Silica-Supported Phosphine–Gold Complexes as an Efficient Catalytic System for a Dearomative Spirocyclization
Bibal, Brigitte,Buffière, Sonia,Cao, Zhen,Nlate, Sylvain,Oda, Reiko,Pouget, Emilie,Scalabre, Antoine
supporting information, p. 427 - 433 (2020/12/03)
The combination of metal catalyst and inorganic silica frameworks provides a greener approach to recyclable catalysis. In this study, three phosphine–gold chloride complexes have been successfully covalently grafted onto chiral silica nanohelices. The resulting 3D ensembles showed chiroptical properties that allowed the monitoring of the supported ligands. The heterogeneous gold chloride catalysts in cooperation with silver triflate exhibited high reactivity in various reactions, especially in the spirocyclization of aryl alkynoate esters, for which a catalytic loading of 0.05 mol % could be employed. The heterogeneous catalysts could be easily recovered and recycled seven or eight times without any loss of efficiency. By adding more silver triflate, 25 cycles with full conversion were achieved owing to a complex catalytic system based on silica and metallic species.
Electrophilic Phosphonium Cation-Mediated Phosphane Oxide Reduction Using Oxalyl Chloride and Hydrogen
Stepen, Arne J.,Bursch, Markus,Grimme, Stefan,Stephan, Douglas W.,Paradies, Jan
supporting information, p. 15253 - 15256 (2018/10/24)
The metal-free reduction of phosphane oxides with molecular hydrogen (H2) using oxalyl chloride as activating agent was achieved. Quantum-mechanical investigations support the heterolytic splitting of H2 by the in situ formed electrophilic phosphonium cation (EPC) and phosphane oxide and subsequent barrierless conversion to the phosphane and HCl. The reaction can also be catalyzed by the frustrated Lewis pair (FLP) consisting of B(2,6-F2C6H3)3 and 2,6-lutidine or phosphane oxide as Lewis base. This novel reduction was demonstrated for triaryl and diaryl phosphane oxides providing access to phosphanes in good to excellent yields (51–93 %).
A rhodium triphenylphosphine catalyst for alkene hydrogenation supported on neat superparamagnetic iron oxide nanoparticles
Dehe, Daniel,Wang, Lei,Müller, Melanie K.,D?rr, Gunder,Zhou, Zhou,Klupp-Taylor, Robin N.,Sun, Yu,Ernst, Stefan,Hartmann, Martin,Bauer, Matthias,Thiel, Werner R.
, p. 127 - 136 (2015/03/05)
A phosphonic acid functionalized triphenylphosphine rhodium complex was synthesized and grafted onto neat superparamagnetic iron oxide nanoparticles. The material was investigated by elemental analysis, IR spectroscopy, thermogravimetric analysis, XRD, N2-physisorption analyses, and TEM measurements. The obtained hybrid material could be used as a catalyst for the hydrogenation of alkenes with excellent yields and a broad substrate scope. The catalyst can be reused ten times without any loss of activity. According to the results from X-ray absorption spectroscopy, it is likely that formation of Rh nanoparticles occurs during the reaction.