Regio- and stereoselective iodofluorination of alkenes with bis(pyridine)iodonium(I) tetrafluoroborate

Barluenga, José; Campos, Pedro J.; González, José Manuel; Suárez, José Luis Lafuente; Asensio, Gregorio

doi:10.1021/jo00006a050

Cited by 88 publications

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“…In this regard, tetrafluoroboric acid is very useful due to the low nucleophilic character of the BF 4 ¹ counteranion. When simply the reagent, the acid and the alkene are mixed at low temperature, a clean, regio-and stereoselective iodofluorination takes place [3,4], as also depicted in Scheme 1 for the case of 1c.*Lecture presented at the 5th International Conference on Heteroatom Chemistry (ICHAC-5), London, Ontario, Canada, 5-10 July 1998, pp. 369-512.…”

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confidence: 99%

Transferring iodine: more than a simple functional group exchange in organic synthesis

Barluenga¹

1999

Pure and Applied Chemistry

112

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Some synthetic features of the IPy 2 BF 4 reagent are presented. Among others, its utility to promote unusual 'carbon-carbon' coupling processes will be discussed. Furthermore, the unique iodinating ability of this reagent towards aromatic and other unsaturated systems will be summarized.The rich chemistry of the carbon-iodine bond has made it a particularly rewarding synthetic tool of routine use for the purpose of functional group interconversion. Iodinated compounds are also credited as helpful diagnostic aids when the radioactive isotopes of the element are used [1]. Moreover, the growing presence and impact of hypervalent iodine compounds represents an additional source of interest in iodine containing reagents [2].The bis(pyridinium) iodonium (I) tetrafluoroborate (IPy 2 BF 4 ) is a stable and solid reagent, that acts as a mild source of iodonium ions towards different types of unsaturated compounds, as it will be shown in this article. Initial efforts were devoted to the development of a methodology that can be useful to accomplish vicinal iodofunctionalization of an alkene. Thus, when the reagent is mixed in CH 2 Cl 2 with an alkene and a nucleophile the corresponding products derived from the addition of an iodine atom and the nucleophile across the double bond are formed, for instance MeOH for 1a, in Scheme 1 [3]. Usually, an acid is required to neutralize the supply of pyridine molecules from the iodinating reagent, avoiding the formation of adducts, such as 1b, that incorporate pyridine as a nucleophile through a competition process for the capture of the intermediate iodonium ion. In this regard, tetrafluoroboric acid is very useful due to the low nucleophilic character of the BF 4 ¹ counteranion. When simply the reagent, the acid and the alkene are mixed at low temperature, a clean, regio-and stereoselective iodofluorination takes place [3,4], as also depicted in Scheme 1 for the case of 1c.*Lecture presented at the 5th International Conference on Heteroatom Chemistry (ICHAC-5), London, Ontario, Canada, 5-10 July 1998, pp. 369-512. Scheme 1Addition is the usual outcome of the reaction of IPy 2 BF 4 with alkenes. However, starting from vinylsilanes an easy substitution process occurs, resulting in a very efficient and simple procedure for the iodo-silicon exchange from E 2a, and Z 2b monosubstituted trimethylsilylalkenes, giving rise stereospecifically to the formation of compounds 3a and 3b, respectively (Scheme 2) [5]. Otherwise, this is known to be an elusive transformation.Interestingly, the reagent is also an efficient iodinating agent promoting addition reactions of alcohols to the same alkenylsilanes furnishing compounds 4 (Scheme 3), by simply running the transformation in the presence of the corresponding alcohol as cosolvent [6]. The resulting adducts can be dehydroiodinated with the tertiary base 1,8-diazobicyclo[5.4.0]undec-7-ene (DBU), giving the stereochemically well-defined trisubstituted enol ethers, in a stereospecific manner.The same sequence, but requiring t-butyldimethy...

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Transferring iodine: more than a simple functional group exchange in organic synthesis

Barluenga¹

1999

Pure and Applied Chemistry

112

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“…3 Regarding the stereochemistry of the reaction, it was found that cyclohexene leads exclusively to trans-1-fluoro-2-iodocyclohexane in 89% yield. The regioselectivity of the process is illustrated in the reaction of 1-hexene (eq 2).…”

Section: Universidad De Oviedo Oviedo Spainmentioning

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Bis(pyridine)iodonium(I) Tetrafluoroborate

Barluenga

Tomás

González

et al. 2006

Encyclopedia of Reagents for Organic Synthesis

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“…Recently, we needed to synthesize a number of [ 14 C]-labeled aromatic iodides with a 1,3-disubstitution pattern and found that an alternative strategy to conventional diazotization was required. The reaction of bis(pyridine)iodonium(I)tetrafluoroborate (IPy 2 BF 4 ) in the presence of tetrafluoroboric acid or trifluoromethanesulphonic acid with unsaturated compounds 1 and aromatic substrates 2 has been reported.…”

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confidence: 99%

A convenient synthesis of [¹⁴C]‐labeled aromatic iodides as versatile synthetic intermediates

Jones¹,

Woolley²,

Skagestad³

et al. 2007

Labelled Comp Radiopharmac

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Regio- and stereoselective iodofluorination of alkenes with bis(pyridine)iodonium(I) tetrafluoroborate

Cited by 88 publications

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Transferring iodine: more than a simple functional group exchange in organic synthesis

Transferring iodine: more than a simple functional group exchange in organic synthesis

Bis(pyridine)iodonium(I) Tetrafluoroborate

A convenient synthesis of [¹⁴C]‐labeled aromatic iodides as versatile synthetic intermediates

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Regio- and stereoselective iodofluorination of alkenes with bis(pyridine)iodonium(I) tetrafluoroborate

Cited by 88 publications

References 0 publications

Transferring iodine: more than a simple functional group exchange in organic synthesis

Transferring iodine: more than a simple functional group exchange in organic synthesis

Bis(pyridine)iodonium(I) Tetrafluoroborate

A convenient synthesis of [14C]‐labeled aromatic iodides as versatile synthetic intermediates

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A convenient synthesis of [¹⁴C]‐labeled aromatic iodides as versatile synthetic intermediates