A study of the double bond reactivity in Δ3-cyclohexene derivatives with one polar substituent in the side chain and Me substituents in the ring has shown that the preferred conformation for these compounds, indepenent of their stereochemistry, has the polar group axial, giving rise to supra-annular interaction. Such interaction decreases the nucleophilicity of the ring double bond. A similar study
Enantioselective Diels-Alder Reactions of Carboxylic Ester Dienophiles Catalysed by Titanium-Based Chiral Lewis Acid
作者:Yogesh Choughule、Anand Patwardhan
DOI:10.13005/ojc/320217
日期:2016.4.28
A new titanium-based chiralLewisacid 1 has been developed using (1R,2R)-1,2-bis-(2methoxyphenyl)-ethane-1,2-diol as a chiral vicinal diol ligand. This chiral catalyst was found to exhibit uniformly high enantioselectivity towards carboxylic ester dienophiles in Diels-Alder reactions. The chiral vicinal ligand (1R,2R)-1,2-bis-(2-methoxyphenyl)-ethane-1,2-diol is inexpensive and is easily accessible