Reactions of p-Quinols with Aldehydes and Imines: Stereoselective Access to Polyheterobicyclic and Tricyclic Systems

Dihydrobenzo[1,3]dioxolanones, tetrahydrobenzo[d]oxazolones and heterotricyclic derivatives have been stereoselectively synthesized from p-quinols upon reaction with aldehydes or benzaldimines under basic catalysis. Reactions occurred in an experimentally simple one-pot procedure through a domino sequence of two or three reactions. The choice of 4-(dimethylamino)pyridine (DMAP) or 1,4-diazabicyclo[2.2.2]octane (DABCO) as catalyst and MeOH, tetrahydrofuran (THF), or dichloromethane as solvent was essential to achieve the synthesis of bicyclic dioxolanes from aldehydes or bicyclic or tricyclic N,O-aminals from imines. The stereochemical course of these processes is highly dependent on the nature of the electrophiles.