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An expeditious FeCl₃-catalyzed cascade 1,4-conjugate addition/annulation/1,5-H shift sequence for modular access of all-pyrano-moiety-substituted chromenes.

ABSTRACT: ortho-Alkynyl quinone methides are well-known four-atom synthons for direct [4 + n] cycloaddition in constructing useful oxa-heterocyclic compounds owing to their high reactivity as well as the thermodynamically favored aromatization nature of this process. Herein we report an operationally simple and eco-friendly protocol for the modular and regioselective access of (E)-4-(vinyl or aryl or alkynyl)iminochromenes from propargylamines and S-methylated β-ketothioamides in the presence of FeCl₃, and particularly under undried acetonitrile and air atmosphere conditions. This method exhibits a broad substrate scope and displays nice functional group compatibility, thus providing an efficient access of 3,4-disubstituted iminochromenes.

SUBMITTER: He X

PROVIDER: S-EPMC9682991 | biostudies-literature | 2022 Nov

REPOSITORIES: biostudies-literature

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An expeditious FeCl3-catalyzed cascade 1,4-conjugate addition/annulation/1,5-H shift sequence for modular access of all-pyrano-moiety-substituted chromenes.

He Xinwei X Li Ruxue R Choy Pui Ying PY Duan Jiahui J Yin Zhenzhen Z Xu Keke K Tang Qiang Q Zhong Rong-Lin RL Shang Yongjia Y Kwong Fuk Yee FY

Chemical science 20221103 45

ortho-Alkynyl quinone methides are well-known four-atom synthons for direct [4 + n] cycloaddition in constructing useful oxa-heterocyclic compounds owing to their high reactivity as well as the thermodynamically favored aromatization nature of this process. Herein we report an operationally simple and eco-friendly protocol for the modular and regioselective access of (E)-4-(vinyl or aryl or alkynyl)iminochromenes from propargylamines and S-methylated β-ketothioamides ...[more]

PMID: 36507178

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