55190-63-1

Upstream product

• 5472-13-9 2-methylbenzhydrol 
• 74-88-4 methyl iodide 
• 67-56-1 methanol 
• 529-20-4 2-methylphenyl aldehyde 
• 108-86-1 bromobenzene 
• 1125-88-8 benzaldehyde dimethyl acetal 
• 2417-95-0 p-tolyllithium 

Downstream Products

• 83984-63-8 C₂₁H₂₂ 

Relevant academic research and scientific papers

Asymmetric nucleophilic substitution of acetals

Benzaldehyde dimethylacetal (1) and 2-aryl-1,3-dioxolanes 5 react with organolithium reagents 2 in the presence of chiral ligands such as sparteine (3), 1-alkoxy-2-aminoethanes, or 1,2-dialkoxyethanes and BF3 to afford monosubstitution products in high yields and in up to 81% enantiomeric excess. The enantioselectivity is strongly influenced by steric effects in the acetal and in the reagent. The highest ee was achieved with 2-(2-isopropyl)-1,3-dioxolane (5c) on treatment with 2-ethylphenyllithium (2i) in the presence of sparteine. The approach was applied to the synthesis of enantioenriched (S)-(-)-neobenodine (17) with 49% ee.

Lithium Dialkylamide Induced 1,4-Elimination of Methyl o-Methylbenzyl Ethers: Formation and Reactions of o-Xylylenes

Lithium dialkylamide induced 1,4-elimination is shown to be a general reaction of methyl o-methylbenzyl ethers, giving o-xylylenes as reactive intermediates.The fate of the intermediates depends on a variety of factors including the base used, the dienophile employed as solvent, or the presence of a suitable located double bond in the substrate.With lithium diisopropylamide (LDA), a significant reaction forms the amine derived from 1,4-addition to o-xylylene.The use of lithium tetramethylpiperidide (LTMP) avoids this addition and allows the study of in situ generated o-xylylene in intermolecular Diels-Alder reactions with simple olefins, where dimerization/polymerization is the major competing pathway.Yields of Diels-Alder adducts range from negligible (cyclohexene) to high (norbornene), with 1-hexene, isoprene, and cyclopentene giving intermediate values.Intramolecular Diels-Alder reactions to form six- and five-membered rings proceed well but are not observed for lower homologue.Second-order rate constants have been obtained for the elimination reaction of some of the substrate ethers, and the effects of structure and temperature on yields of cycloadduct are examined.LTMP is about twice as reactive as LDA in these 1,4-eliminations.