Synthesis of β-Fluorovinyliodonium Salts by the Reaction of Alkynes with Hypervalent Iodine/HF Reagents

Abstract

The reaction of alkynes with PhIO and Py·HF followed by treatment with BF·OEt gave β-fluorovinyliodonium tetrafluoroborates in good to high yields. More conveniently, the reaction using PhI and Py·HF in the presence of m-CPBA also afforded β-fluorovinyliodonium tetrafluoroborates in good yields. These methods have the advantages that β-fluorovinyliodonium salts can be prepared without ArIF.

Convenient access to stable β-fluorovinyl-substituted 1,2-benziodoxolones

“…The synthesis of -fluorovinylbenziodoxolones from o-iodobenzoic acid was examined using 1-octyne as a model substrate according to the similar procedure reported before. 19 o-Iodobenzoic acid was treated with mCPBA and then reacted with HF•pyridine complex and 1-octyne (1a). The reaction mixture was treated with BF 3 •OEt 2 complex, and finally quenched with sodium hydrogen carbonate.…”

“…The best result (Table 1, entry 2) was obtained using o-iodobenzoic acid (0.75 mmol), 1a (0.5 mmol), HF•py (10 mmol HF), and BF 3 •OEt 2 (5 mmol), giving 2-fluoro-1-octenylbenziodoxolone 2a in 84% yield. Yields are determined by 19 F NMR.…”

“…Since we previously developed a convenient synthesis of -fluorovinyliodonium salts using the in-situ preparation of iodosylbenzene from iodobenzene, 19 we applied this procedure to the synthesis of fluorovinyliodonium salts bearing the benzoiodoxolone structure. Thus, we thought to be able to prepare fluorovinylbenziodoxolones from o-iodobenzoic acid.…”

Kitamura Electrophilic Fluorination Using HF as a Source of Fluorine

“…An interesting extension of this reaction cascade was demonstrated for other types of polyfunctional olefins, such as homoallyl alcohols and 3-butenoic acid derivatives [178]. The fluorination-cyclization cascade of homoallyl alcohols 56 (Scheme 19) was performed using the reagent system of PhI(OPiv) 2 and HF/Py in dichloromethane.…”

Synthesis of Multifunctional Aryl(trifloxyalkenyl)iodonium Triflate Salts

“…1 Although the number of applications of these hypervalent reagents increases, the synthesis and utilization of alkenyl derivatives 2 are still a less explored topic of hypervalent iodine chemistry. 3 However, the alkenyl function appears as an important molecular motif in innumerable syntheses of valuable chemical compounds. 4 Therefore, the design of direct alkenylation reactions and multifunctional alkenyl building blocks has great synthetic potential.…”