Organo-Catalyzed Synthesis of 1,2-Dihydroquinolines

Significance

A diphenylprolinol TES-ether-catalyzed synthesis of 1,2-dihydroquinolines in high yields and good to excellent enantioselectivities is reported. The reaction follows a path involving formation of a chiral prolinol enamine intermediate of the α,β-unsaturated aldehyde followed by a Michael addition and an intramolecular aldol reaction with the ortho-aminobenzaldehyde. The scope of the reaction has been reasonably extensively investigated regarding the variation of the unsaturated aldehyde component but not with respect to the aminobenzaldehyde system.