Antimony triflate

Besides the traditional coupling between alkenes and aryl (vinyl) halides, other functionalized aryl derivatives can also couple with alkenes in the Heck reaction, including aryl silanes,stannanes, bismuth, antimony,triflates, boric acid, phosphonic acid, carboxylic acid, and diazonium salt. ... 

Friedel-Crafts Acylation. The Friedel-Crafts acylation of furan was achieved using antimony triflate as catalyst (eq 1). The desired acylated product was afforded in good yield using 5 mol % of the catalyst. 

Antimony triflate was also effective for the acetylation of 2,3-benzofuran leading to the 2-acetylated product as the major isomer (eq 2). ... 

The substrates R OH were partially protected (benzylated and benzoylated) glycosides or thioglycosides. Some glycosidations were greatly promoted by using silica gel. A substantial improvement involved the use of various acid catalysts such as tin (II) triflate or mixtures of antimony (III) and silver perchlorate [53], Similar reactions were performed with BTI (Section 4.5). The conversion of the thiocar-bonyl into carbonyl group using IOB in acetone has been reported in some 2-thiouracils [54],... 

Diels-Alder reaction is one of the premiere reactions in synthetic organic chemistry. The traditional approach to the normal Diels-Alder reaction is to activate the di-enophile by means of a Lewis acid such that the transformation can be carried out under practicable conditions. A variety of Lewis acids catalyze this reaction selectively and among these copper(II) compounds have been very successful in enantioselective transformations. The use of bisoxazolines in combination with copper triflate or copper antimony hexafluoride has afforded high selectivity. Pioneering work in this area by Evans, Jprgensen, Kanemasa, and others has shed light on the different controlling features of the copper Lewis acids. 

P, P] A single example of a stereoselective, Lewis-acid-assisted addition of silyl enol ether to an a,/J-unsaturated thioester has been reported by Mukaiyama and co-workers (76). In this report, silyl enol ether 36.1 was added to thioester 36.2 under the influence of an antimony(V) chloride-tin(II) triflate mixture to give a 94 6 (anti/syn) mixture of diastereomers in 70% yield (Scheme 36). 

P, P] By using antimony(V) chloride and tin(II) triflate, monothioketene acetals can be induced to add to a,/J-unsaturated thioesters (76). Interestingly, neither antimony(V) chloride nor tin(II) chloride by themselves effectively promote the reaction, implying that the combination of Lewis acids produces a new species. The stereochemistry of these additions is summarized in Scheme 44 and Table 16. For all cases studied, the reaction uniformly provides the anti diastereomers with good selectivity. The selectivity observed is somewhat lower than the optimized results observed with thioketene acetals and enones (vide supra). 

Table 3.7 Effect of lithium perchlorate addition on product distribution in the reaction between 2-MN and AAN catalyzed by antimony(lll) triflate...

The reaction of Tf20 with a catalytic amount of antimony(V) fluoride at 25 °C produces trifluoromethyl triflate in 94% yield (eq 42). ... 

Catalytic amounts (5 mol%) of trityl chloride and tin(II) chloride, or antimony(V) chloride and tin(II) triflate, have also been used to promote the Michael additions, with stereoselectivity in favor of the anti isomers and slightly reduced ratios in comparison with the above results. No stereoselectivity was observed with catalytic amounts (10 mol %) of ytterbium(III) trifluoromethanesulfonate. ... 

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