Synthesis of Indole‐Fused Eight‐Membered Oxa‐Rings via Palladium‐Catalyzed Asymmetric [4+4] Cycloaddition of Indole‐2,3‐Quinodimethanes with 2‐Alkylidenetrimethylene Carbonates

Comprehensive Summary We report a palladium‐catalyzed asymmetric [4+4] cycloaddition reaction between 2‐alkylidenetrimethylene carbonate and electron‐deficient indole‐2,3‐quinodimethanes ( IQDMs ). This reaction features exclusive regioselectivity, high yield (up to 98%), excellent enantioselectivity (up to 95% ee), and easy scale‐up without any loss of efficiency, making it valuable for the synthesis of indole‐fused eight‐membered oxa‐rings.