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

摘要

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 degrees 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 degrees C), and then react with the same electrophiles, the final hydrolysis yields the corresponding unsaturated alcohols 7 and 10, respectively.