Coupling of 2H-Chromenes with Silyl Ketene Acetals Enabled by Borane Catalysis

Borane-mediated hydride abstraction has been shown to be a powerful tool for the C(sp3)–H functionalization of amines, but the same activity with ethers is unknown in the literature. Herein, we report that this activity was observed with 2H-chromenes and the catalytic C(sp3)–H functionalization reaction based on this activity was established by using silyl ketene acetals as the nucleophiles.