Secocorrinoid complexes carboxylic acid

The cadmium secocorrinoid carboxylic acid (102 M = Cd) also undergoes photocyclization to the acid (103 M = Cd), which on transmetallation to the nickel(II) complex (103 M = Ni) and treatment with triethylamine and acetic acid yields the parent corrin complex (100 M = Ni).268 The decarboxylation process is extremely facile. A related base-catalyzed cyclization of the secocorrinoid aldehyde (104) gives the corrin complex (105), which can be decarbonylated to the parent complex (100 M = Ni) by treatment with potassium hydroxide (Scheme 66).268... 

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