Base-induced cyclization of 1-benzyloxy-2,2,4,4-tetramethylpentan-3-ones: intramolecular nucleophilic addition of an anion of a benzyl ether to the carbonyl moiety without the Wittig rearrangement or protophilic decomposition

Abstract

Alkyl benzyl ethers bearing a carbonyl moiety in the alkyl chain (1) cyclize effectively, without the Wittig rearrangement or protophilic decomposition, to give hydroxytetrahydrofurans (trans-2) on treatment with Bu^tOK in DMSO at room temperature, whereas LDA–THF induces the cyclization of 1 to afford predominantly the stereoisomer cis-2.