Diphenyliodonium triflate

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... 

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]. 

Elimination of iodobenzene alone from 2-phenyliodonio benzoate leads to generation of another transient 1,4-dipole which was trapped by phosphaalkynes [55], A new precursor, 2-trimethylsilyl-diphenyliodonium triflate, obtained from 1,2-bis-trimethylsilylbenzene, (diacetoxyiodo)benzene and triflic acid, permitted the generation of benzyne with tetrabutylammonium fluoride, at room temperature [56] ... 

This new benzyne precursor combines practical facility in its preparation with relative stability and safety in handling in addition, its conversion into benzyne does not require a strong base or high temperature. Another useful feature of this methodology is that, as with substituted diphenyliodonium 2-carboxylates, only one aryne can be formed from substituted precursors. Indeed, two methyl analogues of 2-trimethylsilyl-diphenyliodonium triflate, in the presence of furan, afforded quantitatively the corresponding adducts high yields of benzyne-diene adducts were also obtained with other 1,3-dienes. 

In contrast with the palladium(IV) metallacycle obtained by reaction with an alkyl halide (Eq. 18) the one shown in Eq. 38 could not be isolated, probably because reductive elimination is much faster. The literature, however, reports that diphenyliodonium triflate can arylate palladium(II) to form a palladium(IV) complex [45]. 

Figure 1 UV Absorption Spectra of Diphenyliodonium Triflate and Photoproducts...

The rate of acid generation from BTf was larger than that of diphenyliodonium triflate(ITf). Deprotection of poly(tert-butyloxycarbonyloxystyrene) (tBOCHS) with BTf was 3 times faster than that with ITf after postexposure bake at same temperature. BTf with higher sensitivity and thermal stability may be expected to be PAG of diazo compounds applicable to microlithography resists. 

Enantioselective a-arylation of aliphatic aldehydes has been achieved by a combination of catalyses by a copper(I)-organocatalyst complex and diphenyliodonium triflate [Ph2-I" OTf] under mild conditions. " ... 

Preparative Methods diphenyliodonium triflate can be prepared by reaction of benzene with elemental iodine in tbe presence of potassium persulfate and trifluoroacetic acid in dicbloroetbane followed by ligand exchange with NaOTf in 71% yield. A one-pot reaction of iodobenzene and benzene with m-CPBA and trifluoromethanesulfonic acid at room temperature for 10 min also affords diphenyliodonium triflate in 92% yield. Diphenyliodonium triflate can be obtained in near-quantitative yield by reacting an excess of benzene (i.e., 4 equiv) with elemental iodine in the presence of m-CPBA and trifluoromethanesulfonic acid. More tedious and somewhat less efficient synthetic routes to diphenyliodonium triflate have been reported using iodosylbenzene (PhIO) or iodobenzene /J-diacetate (PhI(OAc)2), trifluoromethanesulfonic acid, and benzene as starting materials. Another preparation of diphenyliodonium triflate implies the reaction of phenylboronic acid with PhI(OAc)2 and trifluoromethanesulfonic acid in dichloromethane and proceeds in >90% yield. ... 

Handling, Storage, and Precautions described as an air-and moisture-stable, easy to handle, and safe reagent. Diphenyliodonium triflate is mildly light sensitive and should be stored in the dark. 

An enantioselective version of this reaction has been performed in 84% yield and 90% enantiomeric excess by forming the eno-late of 4-tert-butylcyclohexanone with the Simpkins (/f,/f)-base, followed by reaction with diphenyliodonium triflate (eq 3). ... 

Direct a-Phenylations of Cyclic Ketones. Copper enolates obtained by reaction of the corresponding lithiate with stoichiometric amounts of anhydrous copper cyanide react with diphenyliodonium triflate to afford Q ,Q -diphenylated or a-phenylated ketones in moderate yields. Five-membered cyclic ketones gave only Q, o -diphenylated compounds, whereas larger cyclic ketones afford only cK-phenylated products (eq 1). It is noteworthy that copper enolates afford the best yields of phenylated compounds. 

Various a-phenylated cyclohexanones have also been prepared in high yields by reaction of the corresponding lithium enolates with diphenyliodonium triflate (eq 2). The cis/trans ratio depends on the nature of the R group. For example, 4-ferf-butylcyclohexanone affords the phenylated product with a cisitrans ratio >20 1, whereas the ratio is only 5 1 in the case of 4-phenylcyclohexanone and 1 15 if cyclohexanone bears a OTBDMS group at C4. 

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