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Hafnium trifluoromethanesulfonate is a recyclable catalyst for the mononitration of o-nitrotoluene. It serves as a catalyst for homogeneous methoxycarbonylation and hydrocarboxylation reactions of phenylacetylene. It is also used as a reactant for direct Friedel-Crafts reactions of chromene hemiacetals, aminomethylation reactions under Lewis acidic conditions and prins-type cyclization reactions. It is also involved in the direct polycondensation of lactic acid. Further, it is used in cationic benzylation reactions, chemoselective thioacetalization and transthioacetalization of carbonyl compounds.
Lewis acid catalyst introduced by Kobayashi, effective at low concentrations under mild conditions in Friedel-Crafts acylation and alkylation reactions: Bull. Chem. Soc. Jpn., 68, 2053 (1995). Efficient catalyst for the Fries rearrangement of phenolic esters to acylphenols: Tetrahedron Lett., 37, 2053 (1996); Bull. Chem. Soc. Jpn., 70, 267 (1997). Superior to lanthanide triflates as catalyst for atom-economic aromatic nitration with a stoichiometric amount of nitric acid in DCM, avoiding the use of sulfuric acid: Tetrahedron Lett., 39, 1641 (1198); Synlett, 57 (2000). Efficient catalyst for allylations of imines with Allyltri-n-butyltin, L14087, and of Mannich-type reactions of imines with silyl enol ethers: Synlett, 1099 (1997). For use in combination with a catalytic amount of triflic acid for the Friedel-Crafts acylation of aromatics, see: Tetrahedron Lett., 39, 4697 (1998). For use in the catalytic decarboxylative ß-selective glycosylation via a mixed glycosyl carbonate, see: Synlett, 959 (2004). Catalyzes the conjugate addition of indoles to ɑß-enones: Synlett, 2492 (2005).
Ishitani, H.; Suzuki, H.; Saito, Y.; Yamashita, Y.; Kobayashi, S. Hafnium Trifluoromethanesulfonate [Hf(OTf)4] as a Unique Lewis Acid in Organic Synthesis. Eur. J. Org. Chem. 2015, 2015 (25), 5485-5499.
Adams, T. C.; Payette, J. N.; Cheah, J. H.; Movassaghi, M. Concise Total Synthesis of (+)-Luteoalbusins A and B. Org. Lett. 2015, 17 (17), 4268-4271.
Hazard Statements: H315-H319-H335
Causes skin irritation. Causes serious eye irritation. May cause respiratory irritation.
Precautionary Statements: P264b-P271-P280-P302+P352-P304+P340-P305+P351+P338-P312-P332+P313-P362-P501c
Wash face, hands and any exposed skin thoroughly after handling Use only outdoors or in a well-ventilated area. Wear protective gloves/protective clothing/eye protection/face protection. IF ON SKIN: Wash with plenty of soap and water. IF INHALED: Remove to fresh air and keep at rest in a position comfortable for breathing. IF IN EYES: Rinse cautiously with water for several minutes. Remove contact lenses, if present and easy to do. Continue rinsing. Call a POISON CENTER or doctor/physician if you feel unwell. If skin irritation occurs: Get medical advice/attention. Take off contaminated clothing and wash before reuse. Dispose of contents/ container to an approved waste disposal plant