Yttrium triflate is a complex inorganic compound of yttrium, fluorine, carbon, sulphur, and oxygen with the chemical formula . This is the yttrium(III) salt of triflic acid.
Properties The compound forms a colorless solid that is highly hygroscopic and forms hydrates. It is soluble in water and soluble in polar organic solvents such as acetonitrile, THF, and methanol.
Yttrium triflate is a specialised Lewis acid catalyst widely used in organic synthesis, particularly in carbon–carbon bond-forming reactions such as the aldol reactions, Diels–Alder cycloaddition, and Friedel–Crafts acylations. It is valued for its stability in water and resistance to decomposition, in contrast to traditional Lewis acids like aluminium trichloride or boron trifluoride.
Synthesis Yttrium triflate is prepared from yttrium(III) oxide and 50% aqueous trifluoromethanesulfonic acid.
The product is crystallised from water or an organic solvent and can be dried to remove excess water.
Alternatively, the compound may be synthesised from yttrium(III) chloride and silver triflate, but the oxide method is preferred for large-scale preparation.
Uses The compound catalyzes aldol reactions and cycloadditions. It can be fixed to silica to obtain a heterogeneous catalyst for Michael additions and Diels-Alder reactions. Other reactions catalyzed by yttrium triflate include the polymerization of caprolactone, the trimerization of nitriles to triazines, and the addition of amines to nitriles to form amidines.
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