Efficient synthesis of halo indanones via chlorosulfonic acid mediated Friedel–Crafts cyclization of aryl propionic acids and their use in alkylation reactions
... Tetrahedron. Volume 63, Issue 2, 8 January 2007, Pages 389–395. ... 2d and 2e A variety of Lewis acids catalyze this reaction including AlCl 3 , 3, 3a, 3b, 3c and 3d TiCl 4 , 4, 4a, 4b, 4c and 4d polyphosphoric acid, 5, 5a, 5b and 5c methanesulfonic acid, 6 HF, 7, 7a and 7b P 2 O 5 ...