Diphenyliodonium tetrafluoroborate

It has been reported that diphenyliodonium triflate reacts with the lithium enolates of some cyclic ketones in the presence of copper cyanide to yield the corresponding a-phenylated or a-diphenylated ketones.58 There has been a detailed analysis of the products of thermal decomposition of diphenyliodonium tetrafluoroborate and hexafluorophosphate salts.59... 

The catalytic influence of 18-crown-6 on the production of fluorobenzene from diphenyliodonium tetrafluoroborate and KF in dichloroethane was documented some years ago [123]. More recently, diaryliodonium salts have been used for direct syntheses of [18F]-fluoroarenes [124,125]. After an initial study in which various counterions were surveyed, this was finally accomplished by the treatment of diaryliodonium triflates and trifluoroacetates with 18F K+-APE 2.2.2 (i.e., the aminopolyether 4,7,13,16,21,24,27-hexaoxa-l,10-diazabicyclo-[8.8.8]hexacosane) or Cs 18F in acetonitrile (Scheme 44). An added feature of these studies is rather extensive confirmation that nucleophiles are preferentially directed to the more deactivated ring of unsymmetrical diaryliodonium ions, unless one of the rings possesses ortho-substituents [125]. 

Ethylene reacted with iodonium salts in the presence of a palladium catalyst and a base to afford directly 1,2-bis arylated products (stilbenes). Styrene underwent arylation under similar conditions [44], Allylic cyclic carbonates were efficiently phenylated by diphenyliodonium tetrafluoroborate because of the mild conditions, no ring opening occurred, as was the case when iodobenzene was used. 

Pyridine was also phenylated at nitrogen by diphenyliodonium tetrafluoroborate, to jY-phenylpyridinium tetrafluoroborate (88%) [68]. The less polar bromide did not react, whereas the chloride in aqueous pyridine led to the formation of C-phenylated pyridines [69]. 

Cationic polymerization of thiiranes CMT (9-(thiiran-2-ylmethyl)-9//-carbazole) 217 and PMT (10-(thiiran-2ylmethyl)-1077-phenothiazine) 218 was studied by a Lithuanian group <2002JPH63>. Initiators were di-(/-butylphenyl)iodonium tetrafluoroborate (BPIT), diphenyliodonium tetrafluoroborate, cyclopropyldiphenylsulfonium tetrafluoroborate, and ( 7 -2,4-cyclopentadien-1 -yl) [1,2,3,4,5,6- )-( 1 -methylethyl)benzene]-iron(- -)-hexafluorophosphate(—1). The influences of temperature and initiator concentration on the polymerization rate and the conversion limit were determined. The values of initiator exponent and activation energy for the photopolymerization of CMT and PMT initiated with BPIT in 1,2-dichloroethane was established. 

Diphenylliodonium salts react with amines in the presence of a copper catalyst. Diphenyliodonium tetrafluoroborate, Ph2l+BF4, reacts with indole in DMF at 150°C with a Cu(OAc)2 catalyst, for example, to give A-phenylindole. ... 

Table 2.11 Influence of additives on the reaction of diphenyliodonium tetrafluoroborate with sodium...

The bicyclic and tricyclic tetrazoles ((1), (9), and (10)) could also be arylated <85M1227> directly by diphenyliodonium tetrafluoroborate with a similar regioselectivity as was shown in the alkylation reactions. Thus, l-phenyltetrazolo[l,5-u]pyridinium fluoroborate (17 R = Ph, X = Bp4) and 2-phenyltetrazolo[5,l-u]isoquinolinium fluoroborate (19 R = Ph, X = BF4) were prepared. 

Regioselectivity of methylation reactions of pyrido[2,l-/][l,2,4]triazinium-4-olates and 4-thiolates (obtained from the 4-olates with P2S5) (68 X = 0 or S) was studied <88JHC437, 90JHC1673>. With methyl iodide, 3-NMe and SMe derivatives, respectively, were exclusively formed. Mixtures of (69) and (70) were obtained with trimethyloxonium fluoroborate (Equation (4)). Phenylation of the 4-olate with diphenyliodonium tetrafluoroborate gave a 3-NPh derivative, whereas phenylation of the 4-thiolate afforded 4-SPh derivatives of type (70 X = S)... 

Single-crystal X-ray structures have been reported for the following aryl- and heteroaryliodo-nium salts diphenyliodonium triiodide [412], (2-methylphenyl)(2-methoxyphenyl)iodonium chloride [413], (2-methoxy-5-methylphenyl)(4-methoxy-2-methylphenyl)iodonium trifluoroacetate [414], (2-methoxy-5-methylphenyl)(4-methoxyphenyl)iodonium trifluoroacetate [415], a complex of diphenyliodonium tetrafluoroborate with pyridine [416], a complex of diphenyliodonium tetrafluoroborate with 1,10-phenanthroline [417], a complex of diphenyliodonium tetrafluoroborate with 18-crown-6 [418], 1-naphthylphenyliodonium tetrafluoroborate [419], 3,10-dimethyl-10//-dibenzo[, e]iodinium tetrafluoroborate [420], aryl(pentafluorophenyl)iodonium tetrafluoroborates [421], 4,4 -[bis(phenyliodonium)]-diphenylmethane ditriflate [422], [bis(4-methoxyphenyl)](diethylaminocarbodithioato)iodine(in) [423], di(p-tolyl)iodonium bromide [424], diphenyliodonium chloride, bromide and iodide [425,426], diphenyliodonium nitrate [427], diphenyliodonium tetrafluoroborate [428], thienyl(phenyl)iodonium salts [401], (anft-dimethanoanthracenyl)phenyliodonium tosylate and hexafluorophosphate [429] and 3-mesityl-5-phenylisoxazol-4-yl(phenyl)iodonium p-toluenesulfonate [409]. 

Cationic iodonium and sulfonium salts of strong acids are well known as UV-activatable strong acid sources, but they have also found use as heat-activatable acid sources in epoxy resins. Diaryliodonium salts, such as diphenyliodonium tetrafluoroborate (67), have found use with activators, e.g., benzopinacol, in epoxy adhesive and coating formulations. Cure times of several minutes at 160 C were claimed, with good room temperature latency. In a series of patents issued to Asahi Denka Kogyo K.K., several strong acid salts of aliphatic sulfonium compounds have been described as catalysts in heat curing epoxy compositions (68). " The counteranions... 

Related Reagents. Diphenyliodonium tetrafluoroborate diphenyliodoniumhexafluorophosphate diphenyliodonium chloride diphenyliodonium nitrate. 

O-Functionalization. The oxygen atom of the IV-oxide can be alkylated under various reaction conditions methyla-tion, for instance, uses trimethyloxonium tetrafluoroborate in dichloromethane (eq 4). The corresponding o-arylation is quantitative and is carried out in the presence of diphenyliodonium tetrafluoroborate in refluxing acetonitrile. A common aspect of the reactivity of 4-methoxypyridine M-oxide is its ability to bind to metals and serve as ligand in the preparation of organometal-lic complexes. This includes the formation of new and well-characterized palladium, platinum, rhodium, and iron species. O-Functionalization is often used to enhance the reactivity of the C2-position as described in the following section. 

Arylations of weak organic nucleophiles are best achieved with iodonium salts possessing nucleofugic anions and, in some cases, can be facilitated with transition metal catalysts. Recent examples include Cu(II)-catalyzed S-phenyla-tions of 1-benzothiophenes with diphenyliodonium triflate [118], and Co(II)-catalyzed N-arylations of imidazoles with diaryliodonium tetrafluoroborates (Scheme 42) [119]. 

The UV sensitivity of the polyphthalaldehyde-onium salt system is dependent on the concentration and structure of the onium salts. At 10 wt% loading the sensitivity to narrow band width 254 nm radiation is 1-7 mJ/cm2 and is insensitive to the structure of the salts. However, at 2 wt% loading of triphenylsulfonium or diphenyliodonium hexafluoroarsenates or -hexyloxybenzenediazonium tetrafluoroborate much higher doses are required to achieve self-development and the sensitivity decreases with the salt structures in the sequence listed. 

Diphenyliodonium chloride and tetrafluoroborate undergo light-catalyzed reaction with triphenylphos-phine to give tetraphenylphosphonium salts (Equation 110.9). 

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