The reaction of n-butyllithium and potassium t-amyloxide with butenes

1-Butene, cis/trans-2-butene and 2-methylpropene were polymetalated by treatment with the product obtained by combination of n-butyllithium and potassium t-amyloxide. Polymetalation was determined by quenching with deuterium oxide and analysis by gas chromatograph-mass spectrometer combination. The rate of metalation was followed by n-butane evolution. Approximately 20% of cis-2-butene exclusively was realized after H₂O quench of the reaction of 1-butene/n-butyllithium/ potassium t-amyloxide for 1.0 h at room temperature. A small amount (7%) of a cis/trans-2-butene mixture was isomerized to 1-butene and the remaining 2-butene was enriched in the cis-isomer. The assumption that n-butylpotassium was the active metalating species was confirmed by the dependency on lithium/potassium ratio, relative ease of organometallic decomposition at 70°, rapid reaction with monochlorostyrene at room temperature, and the similarity to organosodium and organopotassium isomerization of olefins.