Figure 4: Completion of the total synthesis of (±)-atropurpuran (3). | Nature Communications

Figure 4: Completion of the total synthesis of (±)-atropurpuran (3).

From: Total synthesis of atropurpuran

Figure 4

Conditions: (a) SOCl2, Py., 0 °C; (b) TsOH, acetone/H2O (10:1), 40 °C, 67% over two steps; (c) Ph3PCH3Br, t-BuOK, PhMe, rt, 75%; (d) Me3SI, t-BuOK, DMSO, THF, rt, 68%; (e) BF3·OEt2, PhMe, –20 °C, 92%; (f) TBAF, THF, reflux; (g) DMP, CH2Cl2, rt, 76% over two steps (∼1:1 dr); (h) t-BuOK, MeI, t-BuOH, rt; then 3N HCl, THF, 44% (75% brsm, 5:1 dr); (i) SeO2, t-BuO2H, CH2Cl2, 30 °C, 72% (5:1 dr); (j) DMP, CH2Cl2, rt, 76%; (k) NaBH(OMe)3, THF/MeOH (10:1), −30 °C, 85% (20:1 dr). DMP, Dess-Martin periodinane; THF, tetrahydrofuran.

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