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Bran-New Four-Molecule and Five-Molecule Cascade Reactions for One-Pot Synthesis of Pyrano[3,2‑c]chromen-5-ones and Spiro[benzo[b][1,4]diazepine-2,2′-pyrano[3,2‑c]chromen]-5′-ones under Catalyst- and Solvent-Free Conditions

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journal contribution
posted on 18.10.2018, 16:36 by Guoxun Zhu, Zhou Yi, Jie Zhou, Zhiyong Chen, Pengran Guo, Yanying Huang, Jianghan Chen, Huacan Song, Wei Yi
Herein, two versatile bran-new methods have been developed for building three new kinds of complicated-framework compounds including 2,4,4-trimethyl-2-(phenylamino)-3,4-dihydro-2H,5H-pyrano­[3,2-c]­chromen-5-ones, 4,4,4′,4′-tetramethyl-1,3,3′,4,4′,5-hexahydro-5′H-spiro-[benzo­[b]­[1,4]­diazepine-2,2′-pyrano­[3,2-c]-chromen]-5′-ones, and 2,2,4′,4′-tetramethyl-2,3,3′,4′-tetrahydro-5H,5′H-spiro­[benzo­[b]­[1,4]-oxazepine-4,2′-pyrano­[3,2-c]­chromen]-5′-ones in a one-pot manner via four-molecule and five-molecule cascade reactions of commercially available 4-hydroxychromen-2-one, substituted anilines, and acetone. In consideration of these impressive features including no need of additional catalysts and solvents, moderate to good yields, excellent site-selectivity, and broad substrate/functional group tolerance, we believe that the two present protocols should have the potential for broad synthetic utility.