American Chemical Society
ja7b09186_si_009.cif (418.22 kB)

Total Synthesis of Longeracinphyllin A

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posted on 2017-09-28, 00:00 authored by Jian Li, Wenhao Zhang, Fei Zhang, Yu Chen, Ang Li
The first and asymmetric total synthesis of longeracinphyllin A, a hexacyclic Daphniphyllum alkaloid, has been accomplished. A tetracyclic intermediate was prepared through silver-catalyzed alkyne cyclization and Luche radical cyclization. A phosphine-promoted [3 + 2] cycloaddition reaction was exploited to construct the sterically congested E ring bearing vicinal tertiary and quaternary centers. The cyclopentenone motif was assembled by using intramolecular Horner–Wadsworth–Emmons olefination. Raney Ni reduction delivered the tertiary amine from a thioamide precursor at a late stage.