Robert George Syvret

On the relative power of electrophilic fluorinating reagents of the NF class

Abstract Electrochemical measurements have been employed as a measure of the relative chemical reactivity of a series of NF class electrophilic fluorinating reagents. A correlation has been found between the potential for the first one-electron reduction of the reagents and their observed reactivity in synthetic fluorination reactions. Comparative electrochemical data in acetonitrile and dimethylformamide are reported.

1-Alkyl-4-fluoro-1,4-diazoniabicyclo[2.2.2]octane salts: a novel family of electrophilic fluorinating agents

Members of a new series of solid, easily handled, storable, transportable, commercially viable, site-selective electrophilic fluorinating agents of the +N–F class (tradenamed Selectfluor reagents) have been synthesized via direct fluorination of monoquaternary salts of 1,4-diazabicyclo[2.2.2]octane.

Industrial scale production of Selectfluor™ fluorination agent: from initial concept to full scale commercial production in a 5 year period

Abstract The Selectfluor™ electrophilic fluorination agent 1 is now produced in multi-ton per year quantities and is one of only a few fluorine-containing fine chemicals that are produced by direct fluorination with F 2 on an industrial scale. From the initial concept of the “ideal fluorination agent” to the present day industrial scale production of Selectfluor™, the route to the successful commercialization included a series of critical steps. A chronological account of the road to commercialization of Selectfluor™, noting the important product development factors, is provided herein.

N-Halogeno compounds. Part 14. “Transfer fluorination” of quinuclidine using F-TEDA-BFc (SelectfluorTM reagent): laboratory synthesis of N-fluoroquinuclidinium salts not requiring the use of elemental fluorine

Abstract N Fluoroquinuclidinium tetrafluoroborate ( 1b ) has been prepared in excellent yield by “transfer fluorination” of quinuclidine with 1 chloromethyl-4-fluoro-1,4-diazoniabi cyclo [2.2.2]octane bis(tetrafluoroborate) (F-TEDA BF 4 , Selectfluor TM reagent), which will also effect N -fluorination of pyridine and 2,4,6-trimethylpyridine.

Direct fluorination of bis(trifluoromethanesulfonyl)imide and its lithium salt and related studies

Abstract Studies on the direct fluorination of the acidic imide (CF3SO2)2NH and of its lithium salt (CF3SO2)2NLi have enabled us to establish a potentially-viable commercial route to N-fluorobis(trifluoromethanesulfonyl)imide, (CF3SO2)2NF, and to carry out hazard testing on this well-known electrophilic fluorinating agent.

The formation of halogenated succinates by liquid-phase direct fluorination with elemental fluorine

Abstract Direct fluorination of maleic anhydride with elemental fluorine has been investigated in different solvents at low temperatures. It was discovered that the net conversion of maleic anhydride, as well as the overall yield and composition of the halogenated products, depend strongly on the experimental conditions employed. Fluorinations conducted in fluorotrichloromethane, chloroform or mixtures thereof, in the presence of sodium fluoride, resulted in good yields of halogenated succinic acid derivatives: the predominant products being 2,3-dihalogenated succinic acids. Product distributions varied widely between experiments conducted at 0 °C and −25 °C, and also between experiments conducted in neat CHCl 3 and in CFCl 3 /CHCl 3 mixtures. Experimental details and some comments regarding the stereoselectivity of halogen addition are provided.

N-fluoro triethylene diamine derivatives. Applications to the site selective fluorination of organic compounds.

Abstract The bridgehead-amine derived electrophilic fluorinating reagent, 1-Fluoro-4-alkyl-1, 4-diazonia-bicyclo [2,2,2] octane ditriflate or ditetrafluoroborate (see structure below) prepared from 1-alkyl-Triethylene Diamine salts and elemental fluorine has proven to be very useful for the fluorination of a wide variety of nucleophilic organic substrates. One application of these reagents is the synthesis of α-fluoroketones via an intermediate enol ether, acetate or enamine. This technique has been successfully used to obtain a high yielding site selective fluorination of steroids with very high stereoselectvity. The fluorination of carbanions to produce alkyl and aryl fluorides represents another application of these reagents. The fluorination of aromatic compounds via an electrophilic aromatic substitution process and the directed fluorination of o-litho aromatics was carried out with a high degree of efficiency and regiocontrol. Other applications of these reagents include the fluorination of active methylene compounds and olefins. All of these reactions can be explained on the basis of a one-electron transfer mechanism. The high reactivity of these reagents, coupled with the stereo and regioselectivity on fluorination of a wide variety of substrates, serve to make these compounds an ideal source of electrophilic fluorine.