Leveraging Borylcupration for Enantioselective Cascade Spiroannulation: Access to Spirophthalide Boronates

Herein, we report a cascade reaction to produce spirophthalide boronate frameworks efficiently. This protocol involves borylcupration as a cascade triggering reaction followed by intramolecular aldol reaction, hemiacetalization, and subsequent oxidation, allowing the formation of optically pure spirophthalide boronates with excellent enantio- and diastereoselectivity (up to 99% ee and >20:1 dr). Scale-up synthesis and postmethodological manipulation of spirophthalide scaffolds are also achieved.