ABOUT BASES AND SUPERBASES

Butyllithium requires activation in order to become capable of abstrac ting a proton from weakly acidic hydrocarbons like cyclopropanes, simp le olefins, or arenes. The addition of a stoichiometric amount of pota ssium tert-butoxide is a most effective means of enhancing the rate of a hydrogen/metal exchange process. The superbasic alkyllithium/potass ium alcoholate mixtures are endowed not only with an unsurpassed react ivity but also with a surprisingly high selectivity as evidenced by a series of optionally site-selective arene metalations.