Reaction Pathways through a [1,5]‐Hydride Shift Triggered by Acids: Approach to Bridged‐Ring Heterocycles and Polycycles

The [1,5]‐hydride shift/cyclization process as a new C sp³ –H bond functionalization has made tremendous advances over the past decades. Herein, we describe reaction pathways for a [1,5]‐hydride shift that is triggered by acid. In these transformations, the diene isoindoles are generated in situ and undergo a reaction with different dienophiles to provide access to a series of bridged‐ring heterocycles and polycycles in good yields (up to 94 %). In addition, we found that the choice of acid played a critical role and could be used to control the structure of the final product.