Hans-Otto Kalinowski

Isotopenstörung zum nachweis einer cope-umlagerung bei semibullvalenen

Abstract The trideuteriomethyl-semibullvalenes 2 b and 2 c synthesized by new methods via photo-addition of [1,1,1-D3]2-butyne were studied by 13C NMR spectroscopy. It emerges, that both are Cope systems and the trideuteriomethyl group prefers the allyl position.

Interconversion and preparative separation of enantiomeric enamides

Abstract Barriers to rotation about the CN single bond of enamides (Table 1) are rationalised. The barriers of 7 and 8 allow separations of the enantiomers.

13 C-NMR-untersuchungen an substituierten cycloalkenen : I. Trimethylsilylenolether

Zusammenfassung Es werden die 13C-NMR-spektroskopischen Daten von cyclischen Silylenolethern 1a-i im Hinblick auf Elektronenverteilung im Doppelbindungssystem, Konformation des Trimethylsilyloxygrestes sowie Konfiguration der Doppelbindung bei grosseren Ringen diskutiert.

Synthese und Diels-Alder-Reaktionen von Homodehydroisodicyclopentadien

Zusammenfassung Tetracyclic compound 6 is converted via a series of carbeniumion-rearrangements to 7a . This ketone serves as starting material for the synthesis of cyctopentadiene derivatives 4 and 5 . 4 forms Diels-Alder products preferentially from its exo face.

The conformational analysis of benzocycloalkanones using the lanthanide induced shift msthod

The conformations of the benzocycloalkanones 1a - 1d in solution were estimated by the use of the lanthanide induced shift method (LIS of 1H, 13C NMR spectra). The starting geometry was obtained from MNDO calculations. The torsional angle of the carbonyl group with respect to the benzene ring is 0° for compound 1a, 3° for 1b, 56° for 1c and 67° for the eight-membered ring compound 1d. These results are compared with the data obtained by other methods for similar compounds and are discussed with regard to kinetic measurements for solvolysis of chlorobenzocycloalkanes and oxidation of benzocycloalkanols, respectively.