Selektive Synthesen mit Organometallen II: Metallierung und Abwandlung funktionell substituierter Alkene

Abstract

1,4‐Dienes, vinyl ethers, allyl ethers, allyl thioethers and propene‐thiolates are efficiently metalated by butyllithium in the presence of an activator such as potassium t ‐butoxide. Since the solvent, the counter‐ion or the temperature may be varied before subsequent treatment with an electrophilic reagent, the critical ratio of direct vs . vinylogous attack (substitution at the α‐ or γ‐position, respectively) can usually be adjusted within large limits. In many cases stereo‐selectivity is achieved as well.