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)]
Keywords: Ethers Role: PRP (Properties) (allyl ; deprotonated; conformational mobility and conformational preferences in deprotonated allyl ethers); Conformation; Conformational transition; Deprotonation; Metalation; Torsional barrier (conformational mobility and ; deprotonated allyl ether conformation
Physical Organic Chemistry
Batiment de Chim. (BCh),Inst. Chim. Org. Univ.,Lausanne-Dorigny,Switz.
written in English.
594-19-4 (tert-Butyllithium); 598-30-1 (sec-Butyllithium); 2565-82-4 (Geranyl methyl ether); 2565-83-5 (Methyl neryl ether); 16302-35-5 (3,6-Dihydro-4-methyl-2H-pyran); 22093-99-8 (Methyl prenyl ether) Role: RCT (Reactant), RACT (Reactant or reagent) (conformational mobility and conformational preferences in deprotonated allyl ethers); 63500-69-6P; 102861-44-9P; 102861-45-0P; 214557-19-4P; 214557-20-7P; 214557-21-8P; 214557-22-9P; 214557-23-0P Role: SPN (Synthetic preparation), PREP (Preparation) (conformational mobility and conformational preferences in deprotonated allyl ethers)
Record created on 2006-03-03, modified on 2016-08-08