Unprecedented Oxycyanation of Methylenecyclopropanes for the Facile Synthesis of Benzoxazine Compounds Containing a Cyano Group |
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Authors: | Yu‐Chao Yuan Dr Hai‐Bin Yang Prof Dr Xiang‐Ying Tang Prof Dr Yin Wei Prof Dr Min Shi |
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Institution: | State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai, China |
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Abstract: | A novel intramolecular oxycyanation of methylenecyclopropanes is reported that proceeds through oxidative cleavage of the N?CN bond and subsequent palladium transfer from N to O of the amide group. A range of substituted benzod]1,3]oxazines with a cyano group are readily furnished by this newly developed oxycyanation reaction. Tris(4‐trifluoromethylphenyl)phosphine as a ligand has been found to be crucial to effectively promote the transformation with high chemo‐ and regioselectivity. Moreover, the reaction outcome can be significantly affected by the electronic effect of the acyl group attached to the nitrogen atom of methylenecyclopropanes. When R3 is a chloromethyl group, the pyrrolo2,3‐b]quinoline derivative is obtained by thermal‐induced 3+2] cycloaddition of methylenecyclopropane to the methanediimine intermediate. |
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Keywords: | amides benzoxazines intramolecular oxycyanation palladium synthetic methods |
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