Regiodivergent Formal [4+2] Cycloaddition of Nitrosoarenes with Furanyl Cyclopropane derivatives as 4π Components

Cyclopropanes are commonly used as valuable 3-carbon building blocks. Herein, we disclose a different reactivity pattern of furanyl cyclopropanes, which serve as 4-carbon component in Lewis acid-promoted [4+2] cycloadditions with nitrosoarenes to afford 1,2-oxazine derivatives. Importanly, the regioselectivity of the cycloaddition reaction can be controlled by the appropriate choice of the Lewis acid.