Journal article

a-Deprotonated allyl ethers: conformational mobility and conformational preferences

Tert-BuLi is best suited to accomplish an H-metal exchange at the a-position of g-alkyl branched allyl ethers. Rapid torsional equilibration occurs at the g-terminus of the deprotonated allyl unit, while the alkoxy group at the a-site has to occupy the exo position in order to minimize steric repulsions. Introduction of an alkoxy group into the terminal position of a g-branched 2-alkenyllithium lowers the barrier to torsional isomerization slightly (by a few kcal/mol). [on SciFinder (R)]


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