Enantioselective Catalysis of the Aza-Cope Rearrangement by a Chiral Supramolecular Assembly

The chiral supramolecular catalyst Ga{sub 4}L{sub 6} [L = 1,5-bis(2,3-dihydroxybenzoylamino)naphthalene] is a molecular tetrahedron that catalyzes the 3-aza-Cope rearrangement of allyl enammonium cations. This catalysis is accomplished by preorganizing the substrate in a reactive conformation within the host. This work demonstrates that through the use of enantiopure assembly, its chiral cavity is capable of catalyzing the 3-aza-Cope rearrangement enantioselectively, with yields of 21-74% and enantiomeric excesses from 6 to 64% at 50 C. At lower temperatures, the enantioselectivity improved, reaching 78% ee at 5 C. This is the highest enantioselectivity to date induced by the chiral cavity of a supramolecular assembly

GTU - a workbench for the development of natural language grammars

In this report we present a grammar development and testing tool called GTU (German: Grammatik-Testumgebung; grammar test environment). GUT offers a window-oriented user interface that allows the development and testing of natural language grammars under three formalisms. In particular it contains a collection of German test sentences and a uniform and independent lexicon. This lexicon can be adapted to a given grammar via an integrated lexicon interface. GTU has been implemented in Prolog both under DOS and UNIX. It was originally developed as tutoring tool to support university courses on syntax analysis but in its UNIX-version it allows for the development of large grammars. (orig.)Available from TIB Hannover: RO 6844(1994,12) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

Faunistische Untersuchungen im Bereich der Steinzeile Ladenburg (Neckar-km 13,68 - 13,90)

Available from TIB Hannover: RN 4055(1052)+a / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

Operationelle Wasserstands- und Abflussvorhersagen

SIGLETIB: ZS 4060/1: Bes. Mitt.(51) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman