Development of an iron(II)-catalyzed aerobic catechol cleavage and biomimetic synthesis of betanidin

An aerobic iron(II)-catalyzed cleavage of catechols was developed. This reaction allows for the preparation of 2-methoxy-2H-pyrans that can be employed as versatile building blocks for synthesis. The utility of this biomimetic oxidative cleavage is featured in the synthesis of betanidin, a natural colorant with antioxidant properties. Cut and paste: An aerobic iron(II)-catalyzed oxidative cleavage of catechol was developed. This reaction allows the preparation of 2H-pyrans that can be employed as versatile building blocks for synthesis. The utility of this biomimetic cleavage is featured in the synthesis of betanidin, the aglycone of red beets' principal colorant and itself a valuable antioxidant (see scheme).