Phosphine-Catalyzed Enantioselective Dearomative [3+2]-Cycloaddition of 3-Nitroindoles and 2-Nitrobenzofurans
Huamin Wang1, Junyou Zhang1, Youshao Tu2
1Shanghai Key Laboratory of Green Chemistry and Chemical Processes, School of Chemistry and Molecular Engineering, East China Normal University, Shanghai, 200062, P. R. China.
Abstract:
Over the past years, the metal-catalyzed dearomative cycloaddition of 3-nitroindoles and 2-nitrobenzofurans have emerged as a powerful protocol to construct chiral fused heterocyclic rings. However, organocatalytic dearomative reaction of these two classes of heteroarenes has become a long-standing challenging task. Herein, we report the first example of phosphine-catalyzed asymmetric dearomative [3+2]-cycloadditio of 3-nitroindoles and 2-nitrobenzofurans, which provide a new, facile, and efficient protocol for the synthesis of chiral 2,3-fused cyclopentannulated indolines and dihydrobenzofurans by reacting with allenoates and MBH carbonates, respectively through a dearomative [3+2]-cycloaddition.
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