First Asymmetric Synthesis of Quinoline Derivatives by Inverse Electron Demand (IED) Diels-Alder Reaction Using Chiral Ti(IV) Complex

(matrix presented) R1, R2 = (-OCH2CH2-), (-OCH2CH2CH2-), (-CH=CH-CH2-), (-OCH2CH3, H) (R,R)-3-Aza-3-benzyl-1,5-dihydroxy-1,5-diphenylpentane (1) ligated Ti(IV) complex (1-TiCl2) is used as a chiral Lewis acid catalyst for promoting asymmetric IED Diels-Alder reaction between electron-rich dienophiles and electron-poor dienes. Here we introduce a facile route for the synthesis of asymmetric tetrahydroquinoline derivatives using the above-mentioned chiral catalyst reagent in the presence of 4 Å molecular sieves. The reactions proceed with moderate yields and at times high enantioselectivty.