Cyclopropylmethyl- and cyclobutylmethyllithium by an arene-catalyzed lithiation. Stability and reactivity

The reaction of (chloromethyl)cyclopropane 5 and (bromomethyl)cyclobutane 8 with lithium and a substoichiometric amount of DTBB, in the presence of different carbonyl compounds as electrophiles, in THF at −78 °C leads, after hydrolysis, to the corresponding cycloalkyl alcohols 6 and 9, respectively. However, when the same starting materials are lithiated using naphthalene as catalyst in diethyl ether and at higher temperature (0 or 25 °C), and then react with the same electrophiles, the final hydrolysis yields the corresponding unsaturated alcohols 7 and 10, respectively.