Fig. 5. N–H insertion reactions in water. (a) N–H insertion of iron carbenoids into amino acid derivatives catalyzed by a water soluble iron porphyrin in citrate buffer (CBS) reported by Simonneaux. (b) Carbene insertions into N–H bonds of anilines catalyzed by copper or iridium complexes reported by Sivasankar. (c) Iron catalyzed annulation of 1,2-diamines and diazodicarbonyl compounds reported by Lee.