ETHYLENATION OF SECONDARY AND TERTIARY ALKYLLITHIUMS .I. CONDITIONS AND LIMITS OF REACTION

The addition of ethylene to isopropyl- and t-butyllithium, previously reported,3 occurs also with sec-butyl- and cyclohexyllithium, but not with cyclobutyl-, phenyl-, benzhydryl-, or triphenylmethyllithium. An ether or an amine is a necessary catalyst; both are attacked by alkyllithiums, but not at the low temperatures (below – 10°) of these experiments, where the addition of ethylene is still rapid. No other acyclic, unconjugated olefin approaches ethylene in reactivity. The β-alkylethyllithium, which is formed quantitatively, has been characterized in each case both by carbonation to an acid-ketone mixture and by reaction with benzophenone to a tertiary alcohol whose methyl ether gives rise quantitatively in vapor chromatography to a 1,1-diphenylalkene. The ethylenation of secondary and tertiary alkyllithium is a reaction of potential synthetic utility. © 1969, American Chemical Society. All rights reserved.