Convergent Total Syntheses of the Amaryllidaceae Alkaloids Lycoranine A, Lycoranine B, and 2-Methoxypratosine

The title alkaloids, 1, 2, and 3 respectively, have been prepared in a convergent manner by two related routes. The superior one involves C-H functionalization of the relevant 5-methoxyindole at C-7 using Hartwig's protocol and thus forming the corresponding borolated indole that could be coupled with the requisite 2-bromobenzoate to deliver the title natural products. Single crystal X-ray analyses of the synthetically derived samples of compounds 1 and 2 are reported.