Brønsted-Acid-Catalyzed Synthesis of 3-Alkoxy and 3-Sulfamido Indanones via a Tandem Cyclization.

Brønsted-acid-catalyzed allylic substitution reactions of the in situ generated 3-hydroxy indanones with alcohols and sulfamides were investigated, which provided a facile route for the synthesis of a large variety of 3-alkoxy and 3-sulfamido indanones. The key intermediates, 3-hydroxy indanones, were obtained through the intramolecular Meyer-Schuster rearrangement of o-propargyl alcohol benzaldehydes. The resulting 3-benzyloxy indanone could be selectively modified by allylic sulfonamidation and reduction reactions.