Base-promoted elimination of hydrogen fluoride from alkyl fluorides: reactivity and stereochemistry

The alcoholate-promoted dehydrohalogenation of 5-nonyl fluoride and cyclododecyl fluoride, typical straight-chain and, resp., medium-size cyclic substrates, leads to cis- and trans-alkenes in an approx. ratio of 1:3. With bulky bases such as lithium diisopropylamide the trans isomer is 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 prepd. from cyclododecanol. It is, however, readily accessible by bromofluorination of cyclodecene and subsequent redn. of the adduct with stannane. [on SciFinder (R)]


Published in:
Tetrahedron, 44, 10, 2855-63
Year:
1988
Keywords:
Note:
CAN 110:94222
22-4
Physical Organic Chemistry
Inst. Chim. Org.,Univ. Lausanne,Lausanne,Switz.
Journal
0040-4020
written in English.
1501-82-2 (Cyclododecene) Role: RCT (Reactant), RACT (Reactant or reagent) (bromination and fluorination of); 1724-39-6 (Cyclododecanol) Role: RCT (Reactant), RACT (Reactant or reagent) (bromination of); 502-56-7 (5-Nonanone) Role: PROC (Process) (conversion of, to (butylpentyl)trimethylammonium bromide); 2198-44-9 Role: RCT (Reactant), RACT (Reactant or reagent) (dehydrobromination of, kinetics and stereochem. of); 7664-39-3 Role: PRP (Properties) (dehydrofluorination, of nonyl fluoride and cyclododecyl fluoride, mechanism of); 119105-49-6 Role: RCT (Reactant), RACT (Reactant or reagent) (elimination reaction of, kinetics and stereochem. of); 623-93-8 (5-Nonanol) Role: RCT (Reactant), RACT (Reactant or reagent) (fluorination of); 7795-35-9P Role: RCT (Reactant), SPN (Synthetic preparation), PREP (Preparation), RACT (Reactant or reagent) (prepn. and dehydrobromination of, kinetics and stereochem. of); 61682-09-5P Role: RCT (Reactant), SPN (Synthetic preparation), PREP (Preparation), RACT (Reactant or reagent) (prepn. and dehydrofluorination of, kinetics and stereochem. of); 119105-48-5P Role: RCT (Reactant), SPN (Synthetic preparation), PREP (Preparation), RACT (Reactant or reagent) (prepn. and dehydrofluorination of, stereochem. of); 119105-50-9P Role: RCT (Reactant), SPN (Synthetic preparation), PREP (Preparation), RACT (Reactant or reagent) (prepn. and elimination reaction of, kinetics and stereochem. of); 52457-95-1P Role: RCT (Reactant), SPN (Synthetic preparation), PREP (Preparation), RACT (Reactant or reagent) (prepn. and quaternization of); 112650-17-6P; 112710-78-8P Role: RCT (Reactant), SPN (Synthetic preparation), PREP (Preparation), RACT (Reactant or reagent) (prepn. and reductive debromination of); 1129-89-1P; 1486-75-5P; 10405-84-2P; 10405-85-3P Role: SPN (Synthetic preparation), PREP (Preparation) (prepn. of)
Laboratories:




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