@misc{oai:ir.soken.ac.jp:00000208,
 author = {伊藤, 博一 and イトウ, ヒロカズ and ITO, Hirokazu},
 month = {2016-02-17},
 note = {Although most organic reactions are carded out in organic solvents, the use of water in place of organic solvents is becoming an urgent and important theme in current chemistry because of demands for the rapid development of clean chemical technologies.  To promote organic reactions in water, one should solve the solubility problem:  i.e., how can water-insoluble organic substrates be treated in water?  The author's basic idea for solving this problem is to use a water-soluble molecular container which can bind an organic substrate in an organic phase, bring it into the aqueous phase, and then let it react with an aqueous reagent.  If the product formed in the container is subsequently brought back to the organic phase and replaced by an unreacted substrate, the molecular container may act as a reverse phase-transfer catalyst, whose function is opposite to that of common phase-transfer catalysts which bring an tonic aqueous reagent into an organic phase.  When the organic substrate itself makes an organic phase, an organic solvent-free transformation can be achieved.  Only a few examples are known for the reverse phase-transfer catalysts where cyclodextrins are employed as the catalyst.
  Coordination nanocage 1, which was quantitatively self-assembled from ten small components (six Pd (II) metal blocks and four triangular ligands) has been recently found to bind large organic molecules in its spherical cavity.  In addition to the strong binding ability for neutral molecules, the high water solubility of the cage due to a highly charged (12+) framework prompts the author to examine the use of this cage compound as the reverse phase-transfer catalyst.  Accordingly, the author has developed some chemical transformations in aqueous media including olefin oxidation, isomerization, cyclization, cleavage, and disproportionation by exploiting nanocage 1 as a reverse phase-transfer catalyst.
  The present thesis is composed of six chapters.  Chapter I  includes the introduction and the general summary of the thesis.  Following this chapter, large-scale production of cage 1 is discussed in Chapter II.  Previous works on molecular containers or three-dimensional organic hosts required tedious and multi-step syntheses which were impractical for large-scale production.  In contrast, the author established a facile, ten-gram scale synthesis or Pd(II)-linked cage 1 as well as a related macrocycle.  The procedure developed here has been recently employed in the commercial production of this compound (Pd-NanoCage®).
  In Chapter III, nanocage 1 was found to act as a phase-transfer catalyst for Wacker-type oxidation.　 Thus, nanocage 1 promoted the aerobic, aqueous oxidation of styrene and its derivatives with the aid of (en)Pd(NO3)2.　Spectroscopic study showed that styrenes were first bound by the cage and gradually transformed into acetophenones in the aqueous phase.  Interestingly, the reaction was promoted by a double catalysis system:  i.e., nanocage 1 acted as a reverse phase-transfer catalyst while (en)Pd(NO3)2 acted as an oxidation catalyst.
  Chapter IV describes that nanocage 1 also promotes the isomerization of allylbenzene and the intermolecular oxidative cyclization of α-vinylphenols with the aid of (en)Pd(NO3)2 catalyst.  For example, allylbenzene was isomerized into trans-β-methyl styrene in water in the presence of 10 mol% of nanocage 1 and (en)Pd(NO3)2 in water.  Similarly, ο-1-propenylphenol was converted into 2-methylbenzofuran under the same conditions.
  In Chapter V, nanocage 1 was found to promote an oxidative cleavage of a-methylstyrenes with the aid of hydrogen peroxide and an iron (III) reagent.  It is remarkable that the oxidative olefin cleavage is efficiently promoted by inexpensive reagents (H2O2 and Fe(III)).  Concerning the reverse phase-transfer catalysis of nanocage 1, the catalytic cycle should involve the following steps.  First, α-methylstyrene, which itself forms organic phase, is enclathrated by nanocage 1 and transferred into aqueous phase.  (ii) α-Methylstyrene in the cage is oxidized by the action of an iron (III) reagent with hydrogen peroxide.  (iii) Acetophenone us replaced by unreacted α-methylstyrene.
  Finally, in Chapter VI, the author shows disproportionation of 1, 3-cyclohexachene by palladium (II) reagents.  The author found that nanocage 1 or aqueous palladium (II) reagent promotes the disproportionation of 1, 3-cylohexadiene into benzene and cyclohexene in a 1:1 ratio.  The reaction with nanocage 1 was suppressed in the presence of 1, 3, 5-trimethoxybenzene as an inhibitor., 総研大甲第509号},
 title = {Reverse Phase-Transfer Catalysis of a Self-Assembled Coordination Nanocage},
 year = {}
}