Double O-H insertion reactions of cyclic rhodium carbenoids: diastereoselective synthesis of macrocyclic oxindoles

Double O-H insertion reactions of cyclic diazo amides 1 and dihydroxy compounds 2 in the presence of rhodium(II) acetate catalyst have been achieved, which ultimately led to the facile synthesis of prototype bis(3-oxy-1,3-dihydro-2H-indol-2-one) systems. This facile double O-H insertion reaction protocol was successfully applied to synthesize several C₂-symmetric macrocycles having oxindole units incorporated with complete diastereoselectivity.