[3+2] Coupling of Quinone Monoacetals by Combined Acid-Hydrogen Bond Donor

The expeditious and efficient [3 + 2] coupling approach of quinone monoacetals 1 with alkene nucleophiles 2 by the action of an activated Bronsted acid in the presence of a hydrogen bond donor perfluorinated alcohol has been achieved. With the optimized combined acid, the reaction could proceed under mild conditions by only mixing the two reactants to afford the cycloadducts 3 in a short time (within 10 min) with good to quantitative yields.