Fig. 5: The scope of reaction: stage-2 diversification of Diels–Alder products via decarboxylative coupling reactions.

Reaction conditions: 6a to 6e (0.050 mmol) (derived from 4 or 5) were used. aStandard conditions for photo-induced borylation: B2cat2 (0.15 mmol), DMAc (0.50 mL) under 30 W Blue LEDs irradiation, then pinacol (0.20 mmol) and Et3N (0.20 mL). bDerivatized from the corresponding boronates 6g, 6h. See General Procedures K–N 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 by HPLC analysis on a chiral stationary phase. NHPI, N-hydroxyphthalimide; DIC, N,N’-diisopropylcarbodiimide; DMAP, 4-dimethylaminopyridine.