Nano γ-Fe 2 O 3 -Quinuclidine-Based Catalyst as a Recyclable Organic Base for the Diastereoselective Synthesis of Trans-2,3-Dihydrofuro[3,2-C]Coumarins

A nano γ-Fe₂O₃-quinuclidine-based catalyst as a new, magnetically recyclable heterogeneous organic base was synthesised and used in the efficient synthesis of a series of 11 trans-3-aroyl-2-(4-halobenzoyl)-2,3-dihydro-4H-furo[3,2-c]chromen-4-ones by the reaction of N-(2-(4-halobenzoyl)-2-oxoethyl)pyridinium bromide with 4-hydroxycoumarin and an aryl glyoxal. The catalyst was easily isolated from the reaction mixture using a magnetic bar and reused at least 10 times without significant decrease in its activity.