Conditions-ControlledDivergent Annulation of Bicyclo[1.1.0]butanesand Dioxopyrrolidines through Lewis Acid Catalysis

The divergent construction of unique ring systems poses a substantial challenge in organic chemistry. Herein, we describe the Lewis acid-catalyzed divergent annulations of bicyclo[1.1.0]butanes and dioxopyrrolidines. By precisely modulating the catalytic conditions, the identical substrates are directed to selectively undergo one of three different annulation pathways: (3 + 2), (3 + 4), or (2 + 4) cyclizations. This method facilitates the swift construction of diverse and unique ring systems, such as bicyclo[2.1.1]hexanes, oxabicyclo[4.1.1]octanes, and cyclobutanes, which are further amenable to various functional group transformations. Additionally, preliminary mechanistic studies have shed light on the basis of the observed reaction divergence.