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@PHDTHESIS{Khler:61907,
      author       = {Köhler, Manuela},
      othercontributors = {Bolm, Carsten},
      title        = {{N}eue optisch aktive {P}hosphoniumsalze als
                      {P}hasentransferkatalysatoren sowie die {V}erwendung der
                      korrespondierenden {P}hosphane in der asymmetrischen
                      {K}atalyse},
      address      = {Aachen},
      publisher    = {Publikationsserver der RWTH Aachen University},
      reportid     = {RWTH-CONV-123520},
      pages        = {208 S. : graph. Darst.},
      year         = {2003},
      note         = {Prüfungsjahr: 2003. - Publikationsjahr: 2004; Aachen,
                      Techn. Hochsch., Diss., 2003},
      abstract     = {Within this thesis, primary the application of optically
                      active phosphoniumsalts in asymmetric phase transfer
                      catalysis is described. Emphasis is placed on the
                      Darzens-reaction of benzaldehyde and chloroacetophenone.
                      First, achiral phosphoniumsalts were used under variation of
                      the structure of the salt, temperature, reaction time and
                      base. This was followed by the synthesis of polymerbound
                      alkltriphenylphosphonium iodides , which were repeatedly
                      used up to 18 times in a row as phase transfer catalysts. To
                      obtain optically active phosphoniumsalts, first optically
                      active phosphane precursors were quarternised with methyl
                      iodine. Subsequently, phosphoniumsalts were derived from
                      diphenylphosphino benzoic acid amides. The use of
                      diphenylphosphino benzoic acid pentafluorophenol esters
                      paved the way for the synthesis of a wide range of amides,
                      which were obtained by conversion with diverse amines. It
                      was found that sterically demanding substituents in
                      alpha-position to the amide group led to the highest
                      enantiomeric excesses, whereas the enantioselectivity
                      dropped in case of substitution at the beta position. The
                      highest enantiomeric excess was obtained with the methyl
                      phosphonium iodine of ortho-diphenylphosphino benzoic acid
                      coupled with adamantyl glycinole in $36\%$ ee and $13\%$
                      yield. The role of the hydroxy group is not clear yet,
                      however it appears that an sp3-Carbon in alpha-position to
                      the nitrogen of the amide group has an advantage. The
                      application of an "inverse" salt derived from
                      diphenylphosphino aniline, as well as optically active
                      oxosulfoniumsalts and optically active copper complexes, led
                      to racemic products. Quite interesting results were observed
                      with an optically active P-chiral phosphoniumsalts, although
                      products were generated with moderate enantioselectivities
                      and yields $(7\%ee$ and $8\%$ yield). Except two, the
                      corresponding phosphanes are not reported in literature to
                      date. Thus, they were tested as ligands in numerous
                      metal-catalyzed reactions including: rhodium catalyzed
                      hydrosilylation, palladium catalyzed allylic substitutions,
                      hydroamination of cyclohexadiene, hydrovinylation,
                      rhodium-catalyzed 1,2-addition and ruthenium catalyzed
                      transfer hydrogenation.},
      keywords     = {Darzens-Reaktion (SWD) / Asymmetrische Reaktion (SWD) /
                      Phasentransfer-Katalyse (SWD) / Phosphoniumsalze (SWD) /
                      Optisch aktive Verbindungen (SWD)},
      cin          = {100000},
      ddc          = {540},
      cid          = {$I:(DE-82)100000_20140620$},
      typ          = {PUB:(DE-HGF)11},
      urn          = {urn:nbn:de:hbz:82-opus-8269},
      doi          = {10.18154/RWTH-CONV-123520},
      url          = {https://publications.rwth-aachen.de/record/61907},
}