A Facile Synthesis of trans-Fused Pyrano[3,2-c]benzopyrans Catalyzed by Scandium Triflate

Abstract

Scandium triflate has been utilized as an efficient Lewis acid for the intramolecular cycloaddition of o-quinonemethides (generated in situ from salicylaldehydes and unsaturated alcohols) to afford the corresponding trans-fused pyranobenzopyrans in high yields with high selectivity.

Key words

scandium triflate - o-quinonemethides - hetero Diels-Alder reaction - pyranobenzopyrans

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