Cu-Catalyzed [1,3]-Alkoxy Rearrangement/Diels-Alder Cascade Reactions via in Situ Generation of Functionalized ortho-Quinol Imines.

A Cu-catalyzed cascade reaction between N-alkoxyanilines having an electron-donating functional group at the ortho position and dienophiles, such as N-methylmaleimide, styrene, and indene, proceeded via a dearomative [1,3]-alkoxy rearrangement followed by the Diels-Alder reaction, affording the corresponding ketimines with highly functionalized bicyclic skeletons in an efficient and stereoselective manner. Our mechanistic investigations indicated that the [1,3]-rearrangement is the rate-determining process, efficiently suppressing unfavorable side reactions.