BASE-PROMOTED ELIMINATION OF HYDROGEN FLUORIDE FROM ALKYL FLUORIDES: REACTIVITY AND STEREOCHEMISTRY

Article abstract of DOI:10.1016/S0040-4020(88)90021-X

- The alcoholate-promoted dehydrohalogenation of 5-nonyl fluoride and cyclododecyl fluoride, typical straight-chain and, respectively, medium-size cyclic substrates, leads to cis- and trans-alkenes in an approximate ratio of 1:3.With bulky bases such as lithium diisopropylamide the trans isomer may be obtained almost exclusively.In general, the elimination of hydrogen fluoride proceeds very slowly.Increase of the base strength has only a moderate effect on the rates.Electrophilic assistance as provided by lithium cations in media of low polarity can, however, considerably accelerate the reaction. - Cyclododecyl fluoride cannot be prepared from cyclododecanol.It is, however, readily accessible by bromofluorination of cyclododecene and subsequent reduction of the adduct with stannane.