@article{SundermeyerRadiusBurschka1992,
  author    = {Sundermeyer, Joerg and Radius, Udo and Burschka, Christian},
  title     = {Organometall-Imide - h{\"o}hervalente Derivate der d-Metall-S{\"a}uren, 3. Synthese ond Reaktionen von (Pentamethylcyclopentadienyl)(imido)-Komplexen des Molybd{\"a}ns und Wolframs und eine effiziente Strategie zur Synthese der Organometallate NBu\(_4\)[Cp*MO\(_3\)] (M = Mo, W)},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-31884},
  year      = {1992},
  abstract  = {A convenient and new entry into the chemistry of highvalent pentamethylcyclopentadienyl halfsandwich complexes of molybdenum and tungsten is described. The reaction of Mo-(NtBu)\(_2\)Cl\(_2\) or W(NtBu)\(_2\)Cl\(_2\)(py)\(_2\) with Cp*Li (Cp* = \(\eta^5\)-C\(_5\)Me\(_5\)) provides a high-yield route to new complexes Cp*Mo-(NtBu)\(_2\)CI (la) and Cp*W(NtBu)\(_2\)Cl (1 b) which are converted into a variety of diimido, monoimido, and oxo derivatives. Treatment of 1 a, b with MeLi yields the highly volatile methyl derivatives Cp*Mo(NtBu)\(_2\)Me (2a) and Cp*W(NtBu)\(_2\)Me (2b), while protolysis of 1 a, b with an excess of HCI gas leads to selective cleavage of only one imido function with formation of Cp*Mo(NtBu)Cl\(_3\) (3a) and Cp*W(NtBu)Cl\(_3\) (3b). In contrast, protolysis of 1 a, b with aqueous HCI provides a high-yield route to the well-known organometallic oxides [Cp*MoO\(_2\)](μ-0) (4a) and [Cp*WO\(_2\)](\(\mu\)-0) (4b). These two key compounds are easily converted into the organomolybdate and organotungstate salts NBu\(_4\)[Cp*MoO\(_3\)] (5a) and NBu\(_4\)[Cp*WO\(_3\)] (Sb) by cleavage of the M - 0 - M bridge with NBu\(_4\)[OH]. The Xray structure of 3a is reported.},
  subject      = {Pentamethylcyclopentadienderivate},
  language  = {de}
}
@inproceedings{BurschkaBringmannBusseetal.1992,
  author    = {Burschka, Christian and Bringmann, Gerhard and Busse, Holger and Guessregen, Stefan and Schoener, Bernd and Zagst, Rainer},
  title     = {Structure and dynamics of free and metallated benzonaphthopyranones and -pyrans},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-46858},
  year      = {1992},
  abstract  = {First calculations of the structures of metal-free and complexed biaryl lactones and their confrrmation by X-ray crystaIlography, the search for the transition states of their heIimerization processes, and the spectroscopic determination of the heIimerization barriers of related cyclic ethers by DNMR are reported.},
  language  = {de}
}
@article{BringmannOrtmannZagstetal.1992,
  author    = {Bringmann, Gerhard and Ortmann, Thomas and Zagst, Rainer and Schoener, Bernd and Assi, Laurent Ake and Burschka, Christian},
  title     = {+/- Dioncophyllacine A, a naphthylisoquinoline alkaloid with a 4-methoxy substituent from the leaves of Triphyophyllum peltatum},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-31873},
  year      = {1992},
  abstract  = {The isolation and structure elucidation of rac-dioncophyllacine A from the leaves of Triphyophyllun peltatum, is described. Unlike all other naphthylisoquinoline alkaloids, this fully dehydrogenated representative has an additional methoxy group at C-4, the position of which is deduced from NOE results. Dioncophyllacine A has a 7,1' site of the biaryl axis, as in dioncophylline A. Its constitution is confirmed by an X-ray structure analysis, which shows that the crystalline form of this new alkaloid is racemic.},
  subject      = {Dioncophyllaceae},
  language  = {en}
}
@article{BringmannHartungGoebeletal.1992,
  author    = {Bringmann, Gerhard and Hartung, Thomas and Goebel, Lothar and Schupp, Olaf and Ewers, Christian L. J. and Schoener, Bernd and Zagst, Rainer and Peters, Karl and Von Schnering, Hans Georg and Burschka, Christian},
  title     = {Novel concepts in directed biaryl synthesis, IX: Synthesis and structure of benzonaphthopyranones, useful bridged model precursors for stereoselective biaryl syntheses},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-46635},
  year      = {1992},
  abstract  = {A practicable two-step procedure for the preparation of a series of lactone-type bridged biaryls 7 as favorable substrates for subsequent atropisomer-selective ring-opening reactions is described. Due to the efficiency of the coupling step, which tolerates even a telt·butyl group next to the biaryl axis and avoids problems of regioselectivity, a variety of differently substituted representatives is prepared. These cover a broad range of steric hindrance and thus molecular distortion. The structures are investigated mainly by NMR spectroscopy and X-ray diffraction, showing the lactones 7 to be helically distorted, depending on the size of the residues R.},
  subject      = {Chemie},
  language  = {en}
}