Modular Synthesis of gem-Difluorotetrahydrocarbazolone Scaffolds via Copper-Catalyzed Cascade Reaction of Bromodifluoroacetyl Indoles and Olefins. - Yu QH; Luo QY; Ye YH; Wu YF; Wu XP; Zhang ER; Zhuo XY; Du F; Pan B; Liang W (Organic letters, 2024)