@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} } @article{BringmannZagstSchoeneretal.1991, author = {Bringmann, Gerhard and Zagst, Rainer and Sch{\"o}ner, Bernd and Busse, Holger and Hemmerling, Martin and Burschka, Christian}, title = {Acetogenic Isoquinoline Alkaloids. XXIII. Structure of the Naphthyl Isoquinoline Alkaloid Dioncophylline A}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-31331}, year = {1991}, abstract = {No abstract available}, subject = {Chemie}, language = {en} } @article{KuehnBurschkaWerner1982, author = {Kuehn, A. and Burschka, Christian and Werner, H.}, title = {Synthesis and molecular structure of C\(_5\)H\(_5\)(P-/-Pr\(_3\))Pd(η\(^1\), η\(^3\)-C\(_3\)H\(_4\))Pd(P-/-Pr\(_3\))Br: a compound formed through insertion of allene into a metal-metal bond\(^1\)}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-46592}, year = {1982}, abstract = {No abstract available}, subject = {Chemie}, language = {en} } @article{PeachBurschka1982, author = {Peach, Michael E. and Burschka, Christian}, title = {Metal carbonyl complexes of some aromatic ortho bis(methylthio)ethers}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-31964}, year = {1982}, abstract = {Various complexes of the type M(CO)4L and [M(CO)4lzL, M = Cr, Mo, W, have been prepared and characterized. A series of aromatic ortho bis(methylthio)ethers were used as the ligand L. The crystal structures of the free ligand C6(SCH)6 and of the complex Cr(CO)4C6(SCH)6 are reported.}, subject = {Chemie}, language = {en} } @article{RiesAlbrightSilvestreetal.1986, author = {Ries, Wolfgang and Albright, Thomas and Silvestre, Jerome and Bernal, Ivan and Malisch, Wolfgang and Burschka, Christian}, title = {Unusual structural features of a siloxane}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-31925}, year = {1986}, abstract = {Crystals of the R, S diastereoisomer of [Cp(CO)\(_2\)-FeSiCH\(_3\)F]\(_2\)O are monoclinic, space group ndc (No. 14), with a = 846.0(3) [836.4(1»), b = 768.0(3) [757.1(1»), c = 1548.5(4) [1522.3(2)] pm, {3 = 97.34(3t [97.47(3t] at 300 K [120 K] with Z = 2. Even at 120 K the Si-O-Si fragment is found to be strictly linear due to crystallographically imposed symmetry. To explain the unusual electron distribution derived from the X-ray data collected, several types of possible disorders are discussed, none of which leads to a satisfying explanation. Retaining the Ci symmetry (linear Si-O-Si fragment in the final model) the important bond lengths are Fe-Si 226.7(1) [226.5(1)] pm, Si-F 160.9(2) [161.8(2)] pm, Si-O 160.3(1) [161.1(1)] pm, Si-C 185.0(3) [185.6(3)] pm. The electronic features of this compound were probed via molecular orbital calculations of the extended Hiickel type. It was found that the lone pairs on the siloxane oxygen were tipped away from cylindrical symmetry. The tipping was directed toward the fluorine substituents on the silicon atoms and away from the CpFe(CO)\(_2\) units. A pertubational approach was utilized to rationalize this effect.}, subject = {Chemie}, language = {en} }