Dysprosium triflate

Preparative Method dysprosium triflate is commercially available. However, it can be prepared by adding an excess of commercially available Dy(III) oxide to an aqueous solution of tri-fluoromethanesulfonic acid (50% v/v) and heating at reflux for 30 min to 1 h before filtration to remove unreacted oxide. The water can then be removed under reduced pressure, and the hydrate can he dried by heating under vacuum at 180-200 °C for 48 h. 

Mannich-type Reactions. Due to the mild nature of rare earth triflates (RE(OTf)3), and their compatibility with basic nitrogen groups, they have been used extensively in Mannich-t)q)e reactions. Dysprosium triflate has been used to mediate the synthesis of benzotriazole derivatives from lV-(a-benzotriazolyl-alkyl)amides (eq 1). In this case, the more commonly employed Sc(OTf)3 and Yb(OTf)3 failed to produce appreciable quantities of the desired product. 

An intramolecular aza-Piancatelli rearrangement that constructs a fully substituted carbon centre bearing a nitrogen atom and a spirocyclic ring system in a single operation has been catalysed by dysprosium (Ill)triflate. The azaspirocycles are formed exclusively as the irons diastereomer, consistent with a electrocyclization (Scheme 99). ... 

Intramolecular Piancatelli rearrangement of 2-furylcarbinols with alcohols catalyzed by dysprosium(III) triflate led to oxaspirocycles (130L476). 

---