A Combined Tamaru Allylation/Olefin Cross-Metathesis Approach for the Total Syntheses of (±)-Paniculidine B, (±)-Paniculidine C, and 2-Methylcarbazole

Abstract

A concise approach to the total syntheses of racemic paniculidines B and C is described. The route features a combined Tamaru allylation/olefin cross-metathesis sequence for the regiocontrolled synthesis of prenylindole intermediates. In addition, we report a transformation of the prenylated indole into 2-methylcarbazole catalyzed by sulfonic acid-functionalized silica gel.

Key words

prenylindoles - Tamaru allylation - cross-metathesis - carbazoles - total synthesis - alkaloids

• References and Notes

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β-Hydroxysulfonic acid-functionalized silica gel (HO-SAS; Chromatorex-DPR, 0.5 mmol/g of SO₃H) has been commercially developed by Fuji Silysia Chemical Ltd. For applications of HO-SAS as a catalyst in organic synthesis, see:
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