Question

Predict all the alkenes that would be formed by dehydrohalogenation of the following halide with sodium ethoxide in ethanol and identify the major alkene:

Cyclohexylmethylbromide

Answer 1

Cyclohexylmethyl bromide undergoes β-elimination when heated with sodium ethoxide in ethanol, resulting in the removal of HBr and formation of an alkene.

\[\ce{C6H11 - CH2 Br + NaOEt ->[ethanol][]C6H10 = CH2 + NaBr + EtOH}\]

Only one alkene is formed cyclohexylidene methane, is formed by elimination of a β-hydrogen from the ring carbon adjacent to the CH₂Br group.