Silver trifiate

The ring-opening of the cyclopropane nitrosourea 233 with silver trifiate followed by stereospecific [4 + 2] cycloaddition yields 234 [129]. (Scheme 93) Oxovanadium(V) compounds, VO(OR)X2, are revealed to be Lewis acids with one-electron oxidation capability. These properties permit versatile oxidative transformations of carbonyl and organosilicon compounds as exemplified by ring-opening oxygenation of cyclic ketones [130], dehydrogenative aroma-tization of 2-eyclohexen-l-ones [131], allylic oxidation of oc,/ -unsaturated carbonyl compounds [132], decarboxylative oxidation of a-amino acids [133], oxidative desilylation of silyl enol ethers [134], allylic silanes, and benzylic silanes [135]. 

C-Glycosides.1 The (l-thiopyridyl)-p-D-glucopyranose 1 on activation with silver ) trifiate reacts with various carbon nucleophiles to yield C-glycosides in which the a-isomer usually predominates, regardless of the nucleophile, the solvent, or the temperature. 

Acetylenic oxy-Cope rearrangement (12, 51). The oxy-Cope rearrangement of 5-hexen-l-yn-3-ols is accelerated in refluxing N-methyl-2-pyrrolidone (9, 316), but the required temperature (165°) can result in rearranged products. The rearrangement can proceed at 20-60° in the presence of silver trifiate (1 equiv.), which is known to complex with triple bonds.2. ... 

Having found that gold triflates were mesomorphic, we returned to silver and decided to look at other anions. In so doing, we made complexes of silver trifiate and nitrate, each of which exhibited similar patterns of liquid-crystal behavior namely, the formation of Sc and Sa phases at rather elevated temperatures (the phase diagram for the nitrates is reproduced in Fig. 40) (54). While neither of these systems showed a cubic phase, we did find a nematic phase in the triflates. 

The Whitesides group achieved a more efficient synthesis of a-sialosides from sialyl xanthates by modifying the reaction conditions of Sinay s system [11]. Previously, Lonn and coworkers had demonstrated that lower temperatures and the use of milder promoter, methylsulfenyl trifiate, increased the product yield and reaction stereoselectivity [12]. Whitesides and coworkers introduced an even milder promoter, phenylsulfenyl trifiate (PST), which itself was prepared in situ from silver trifiate and phenylsulfenyl chloride [11]. When sialylations of xanthate donor 27 were pro-... 

Solutions of indium (I) can be prepared by treatment of indium amalgam with silver trifiate in dry acetonitrile in the absence of oxygen, and then diluted with water to give the low-concentration aqueous solution, which plays a sizable role in the study of the details of intermolecular electron transfer processes in solution. Aqueous In(I) solution has been used to examine the behavior of this hypovalent center in inorganic redox transformations. Reactions with complexes of the type [(NH3)5Co (Lig)] and [(NH3)5Ru (Lig)] (Lig = Cl , Br , 1 or HC204 ) show two consecutive one-electron reactions initiated by the formation of the metastable state In , which is then rapidly oxidized to In and the first of which is predominating an inner-sphere mechanism. ... 

Again, -pentenyl orthoester 23 (S = Pent) and NPG 26b are both glycosyl donors, but they have very different properties, notably towards acids. Further donor versatility comes from the fact that titration with bromine affords bromide 29b, the classic glycosyl donor, ready for reaction with silver trifiate [18]. 

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