Superoxide hydrolysis, synthesis

By employing anionic techniques, alkyl methacrylate containing block copolymer systems have been synthesized with controlled compositions, predictable molecular weights and narrow molecular weight distributions. Subsequent hydrolysis of the ester functionality to the metal carboxylate or carboxylic acid can be achieved either by potassium superoxide or the acid catalyzed hydrolysis of t-butyl methacrylate blocks. The presence of acid and ion groups has a profound effect on the solution and bulk mechanical behavior of the derived systems. The synthesis and characterization of various substituted styrene and all-acrylic block copolymer precursors with alkyl methacrylates will be discussed. 

Synthesis of bimetallic /r-peroxo complexes has been described by Mimoun. In particular, for Co species reaction between a superoxo complex with a reduced metal is a feasible method, for Pt species acid catalyzed hydrolysis of peroxo complex may be used and for Rh or Pd the protocol implies reaction of potassium superoxide with appropriate precursors. 

In the synthesis of D-ristosamine (388), all that is required is inversion of the 5-methyl group of lactone 393. This is readily accomplished by opening the lactone ring with potassium superoxide, acidification to pH 4, and a Mitsunobu reaction. Once again, reduction of the lactone to lactol (71% yield) followed by Wittig reaction and acid hydrolysis (HCl, methanol) affords the desired sugar 388, isolated as the diacetate in 23% yield [124]. 

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