The first example of glucose-containing Brønsted acid synthesis and catalysis: efficient synthesis of tetrahydrobenzo[α]xanthens and tetrahydrobenzo[α]acridines in water

Glucose sulfonic acid (GSA) was synthesized for the first time and used as an efficient catalyst for the preparation of tetrahydrobenzo[α]xanthens and tetrahydrobenzo[α]acridines via the reaction of aromatic aldehydes, 2-naphthol (or β-naphthylamine), and dimedone in water. Up to four new bonds and one new ring were formed in one-pot with water as the only by-product in these two reactions. The work opens up a new and efficient synthesis and application of sugar-containing Brønsted acid.