Ir(III)‐Catalyzed C−H Alkylation of Aryl Ketone and Chromanone under Mild Conditions; Two‐Step Synthesis of Cytosporones B and N

Abstract

AbstractAn Ir(III)‐catalyzed ortho‐C−H alkylation of aryl ketones with diazo Meldrum's acid was developed for the synthesis of 2‐(2‐alkanoylaryl)acetate derivatives. The reaction took place under mild atmospheric conditions with broad substrate scope. Further, the developed catalytic system was found to be suitable for the selective C5‐alkylation of flavanone and chromanone derivatives. Mechanistic studies revealed that the reaction proceeds via initial Ir(III)‐catalyzed selective ortho‐alkylation followed by decarboxylative esterification with the alcohol to furnish the final product. Notably, the developed reaction was successfully applied in the total synthesis of cytosporones B and N in two steps starting from resorcinol.