Sulfamic acid as a cost-effective and recyclable solid acid catalyst for Friedel-Crafts alkylation o

Sulfamic acid was proved to be a cost-effective and recyclable catalyst for Friedel-Crafts type reaction of indole with α,β-unsaturated carbonyl compound and benzyl alcohol. Various indoles, α,β-unsaturated carbonyl compounds and a benzyl alcohol were successfully used in this type of reaction, and the corresponding products were obtained in good to excellent yields.