Friedel–Crafts-type conjugate addition of indoles using fluorapatite doped zinc bromide as efficient solid catalyst

Fluorapatite doped zinc bromide was found to be a very efficient heterogeneous catalyst for the preparation of 3-substituted indoles from Michael addition of indoles to α,β-unsaturated ketones in good to excellent yields. The substitution on the indole nucleus occurred exclusively at the 3-position, and N-alkylation products have not been observed.