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. ▪