phosphates doped with potassiumfluoride as heterogeneous catalysts for the Michaeladdition of aromatic and aliphatic amines to α,β-unsaturated carbonylcompounds is presented. The natural phosphate catalyst can be regenerated and reused without loss of activity, which makes it an attractive alternative to homogeneous basic reagents. Doping natural phosphate with potassiumfluoride significantly enhances
Natural Phosphate Modified with Lithium Nitrate: A New Efficient Catalyst for the Construction of Carbon–Carbon, Carbon–Sulfur, and Carbon–Nitrogen Bonds
of small amounts of lithium nitrate to natural phosphate followed by calcination gives a new catalyst Li/NP (weight ratio LiNO3/NP = 1/15). This material showed catalytic activity in the Michael addition of amines, mercaptans, and activemethylenecompounds to chalcone derivatives with high yields under mild reaction conditions. Li/NP is used as the catalyst for a facile synthesis of β-amino acids,