Norihiko Yoneda

Electrochemical fluorination of aliphatic aldehydes and cyclic ketones using Et3N-5HF electrolyte

Abstract The first electrochemical oxidative fluorination of aliphatic aldehydes ( 1 ) and cyclic ketones ( 3 ) has been successfully carried out using Base-HF as the supporting electrolyte and fluorine source. The selective displacement of formyl hydrogen by fluorine in aliphatic aldehydes electrochemically took place to give acyl fluorides ( 2 ) in good yields in the presence of the Et 3 N-5HF electrolyte. On the other hand, the selective α-bond cleavage between the carbonyl carbon and substituted α-carbon in cyclic ketones occurred in the presence of the Et 3 N-5HF electrolyte to give fluoroacyl fluorides ( 4 ), which were readily converted in good yields to the corresponding fluorocarboxylic esters ( 5 ) by the subsequent alcoholysis.

Facile preparation of aromatic fluorides by deaminative fluorination of aminoarenes using hydrogen fluoride combined with bases

Abstract One-pot deaminative fluorination of aminoarenes including heteroaromatics, namely, diazotization of aminoarenes followed by in situ fluoro-dediazoniation of the corresponding diazonium ions, was successfully accomplished to produce fluoroarenes in high yields by using hydrogen fluoride combined with base solutions. The diazotization stage has been found to play the most important part in yielding fluoroarenes effectively. It was greatly influenced by the composition of the HF solution and enhanced by employing appropriate amounts of bases such as pyridine under carefully controlled conditions. The fluoro-dediazoniation stage was effectively accelerated photochemically to afford fluoroarenes having polar substituents such as hydroxyl, nitro and so on in high yields.

Fluorocyclization of unsaturated alcohols and carboxylic acids by iodotoluene difluoride and amine-HF complexes

Abstract In the presence of amine-HF complexes, iodotoluene difluoride reacted with unsaturated alcohols and carboxylic acids to give cyclic fluoroethers and fluorolactones, respectively.

Advances in the preparation of organofluorine compounds involving iodine and/or iodo-compounds

Abstract The intriguing properties of iodine have drawn the attention of organic chemists. In this paper, we will describe the recent development of stereo- and/or regioselective synthesis of fluorine-containing organic compounds employing hypervalent iodine fluorides such as ArIF 2 ( 1 ), IF 5 ( 22 ), and ( E )-2-fluoro-alk-1-enyl-4-aryl iodonium salts R(F)C=C(H)IF–Ar ( 12 ). The electrochemical fluorination procedures involving iodo-compounds will also be presented to prepare fluoro-organic compounds.

A facile preparation of fluoropyridines from aminopyridines via diazotization and fluorodediazoniation in HF or HF-pyridine solutions

Abstract Fluoropyridines were prepared in high yields by the diazotization of aminopyridines in HF or HF-pyridine solutions, followed by dediazoniation in situ at 20 - 60 °C.

Electrochemical fluorination of β-dicarbonyl compounds using p-iodotoluene difluoride as a mediator

Abstract The selective and direct introduction of the fluorine atom into the α-position of β-dicarbonyl compounds was electrochemically achieved using iodotoluene difluoride as the mediator. The resulting α-fluoro-β-dicarbonyl compounds are important building blocks for biologically active compounds.

Stereoselective synthesis of (E)-1-fluoro-1,3-enynes

Abstract 1-Fluoro-1,3-enynes were stereoselectively prepared by the cross-coupling reaction of 1-alkynes with β-fluoroalkenyliodides obtained from (β-fluoroalkenyl)iodonium salts. As the reaction proceeds under mild conditions, polyfunctionalized 1-fluoro-1,3-enynes could be prepared, and the synthesis of a fluorinated analog of a natural compound was achieved using this method.

Stereoselective synthesis of (E)-β-fluoro-α,β-unsaturated esters by carbonylation of (E)-2-fluoro-1-iodo-1-alkenyliodonium salts

Abstract ( E )-β-Fluoro-α,β-unsaturated esters were stereoselectively obtained by the palladium-catalyzed carbonylation reaction of ( E )-2-fluoro-1-iodo-1-alkenyliodonium salts obtained by the addition of iodotoluene difluoride to 1-alkynes.

Fluorinative ring-contraction of cyclic alkenes with p-iodotoluene difluoride

Fluorinative ring-contraction of cyclic alkenes is induced by iodotoluene difluoride and Et3N-5HF to give difluoro cycloalkanes selectively.

Fluorinative ring-expansion of cyclic ethers using p-iodotoluene difluoride. Stereoselective synthesis of fluoro cyclic ethers

Fluorinated five- to seven-membered cyclic ethers were stereoselectively synthesized from four- to six-membered cyclic ethers having an iodoalkyl substituent by fluorinative ring-expansion reaction using p-iodotoluene difluoride.