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Cercosporin-Photocatalyzed [4+1]- and [4+2]-Annulations of Azoalkenes Under Mild Conditions
Published on: July 17, 2020
Metal-Assisted Synthesis of Diverse Porphyrinoids by Cyclization of an N-Confused Thia-Pentapyrrane
Hangchong Lu1, Qizhao Li1,2, Fangtao Ma1
1Shanghai Key Laboratory of Functional Materials Chemistry, Key Laboratory for Advanced Materials and Institute of Fine Chemicals School of Chemistry and Molecular Engineering, East China University of Science & Technology, 130 Meilong Road, Shanghai, 200237, China.
Abstract:
Oxidation of thia-pentapyrrane S-P4 with terminal β-linked pyrrole and thiophene units in the presence of various metal ions has been found to afford distinct porphyrinoids. Specifically, N-confused thiasapphyrin (1), Cu(III) norrole (2), neo-confused phlorin (3), and p-benzinorrole (4) were obtained, when S-P4 was oxidized with p-chloranil in acetonitrile in the presence of Ni2+, Cu2+, Cd2+, and Co2+, respectively. The structures of 1-4 have been clearly elucidated by NMR spectroscopy, HRMS, and X-ray crystal diffraction (for 2-4). This work indicates that the oxidative cyclization by linking highly reactive β-linked pyrrole unit with less reactive thiophene unit assisted by various metal ions shows great potential in the construction of various novel porphyrinoids.
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