Copper-Catalyzed Dehydrogenative Formal [4 + 2] and [3 + 2] Cycloadditions of Methylnaphthalenes and Electron-Deficient Alkenes.

Higher π-extended naphthalene, contained in methylnaphthalenes, which could capture alkyl radicals via SOMO-LUMO interactions, enabled the development of Cu-catalyzed formal [4 + 2] and [3 + 2] cycloadditions between methylnaphthalenes and electron-deficient alkenes. Under copper catalysis, a series of electron-deficient alkenes and methylnaphthalenes with different substituents were successfully incorporated with di-tert-butyl peroxide (TBP) as an oxidant and radical initiator, providing a wide range of cycloadducts.