Silver triflate, catalysis

The presence of catalytic amounts of cuprous triflate or silver(I) sulfonates exerts a remarkable influence on the activation energy and regiochemistry of alkynyl(phenyl)-iodonium tosylate and mesylate decompositions5,6. Such reactions proceed in acetonitrile at room temperature and afford moderate yields of alkynyl tosylates and mesylates (equations 82 and 83)5,6. It is noteworthy, however, that the treatment of alkynyliodonium triflates (R = n-Bu, r-Bu) with cuprous triflate in acetonitrile does not afford alkynyl triflates6. Silver(I) catalysis has similarly been applied to the conversion of bis(alkynyliodo-nium) tosylates to bisalkynyl tosylates (equation 84)43. As might be expected, mono-tosylate esters are also produced in these reactions. 

Durkee and co-workers have prepared polyferrocene block copolymers for use in catalysis.223 The reported polymers were synthesized via sequential anionic polymerization of vinylferrocene and isoprene, followed by oxidation using silver triflate. The fraction of ferrocene converted to ferrocenium was directly proportional to the amount of Ag+ added. These materials were tested for their catalytic activity toward the Michael addition reaction of ethyl-2-oxycyclopentane barboxylate and methylvinylketone. These materials showed k values similar in magnitude to the rates of iron(III) chloride. 

The combination of Pd(II)/bis-sulfbxide catalysis with a silver triflate cocatalysis allowed a chemo- and diastereoseleaive C-O allylic functionalization of terminal olefins leading to fw s-2-aminooxazolines 149 as major products from ambident 7V-nosyl urea precursors 148 (13JA12032). Starting from 2-hydroxycycloalkylureas, bicyclic 2-aminooxazolines were synthesized by an intramolecular diethylaminosulfur trifluoride (DAST)-mediated ring closure (13TL5802). 

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