Fig. 4: The scope of reaction: stage-1 diversification of Diels–Alder products via decarboxylative coupling reactions.

Reaction conditions: either 2 or 3 (0.10 mmol) was used. aStandard conditions for arylation: Ni(glyme)Cl2 (20 mol%), dtbbpy (40 mol%), ArZnCl·LiCl (0.30 mmol), DMF (0.50 mL), THF (0.70 mL). bReaction performed at 50 °C. cStandard conditions for photo-induced iodination: LiI (0.20 mmol), PPh3 (10 mol%), acetone (1.0 mL), 30 W Blue LEDs irradiation. dNaI is used as the iodine source, then DBU (0.20 mmol). See General Procedures G–J in the Supplementary Information for detailed conditions. Yields refer to isolated yields. The dr ratios were determined by 1H NMR analysis of the crude mixture. The ee values were determined by HPLC analysis on a chiral stationary phase. tBu, tert-butyl; Bn, benzyl; Ph, phenyl.