Superbases for organic synthesis

Abstract

LICKOR” mixtures of organolithium reagents and bulky potassium alcoholates allow the smooth metalation and subsequent electrophilic substitution of low acidity hydrocarbons, in particular olefins. The allylpotassium intermediates exhibit peculiar conformational preferences which can be exploited in novel stereoselective carbon-carbon linking reactions. A few syntheses of simple natural products illustrate the method. A tentative explanation is given for the superior performance of LICKOR mixtures when compared with butylpotassium. © 1988 IUPAC