0000000000020744
AUTHOR
Jochen Becker
Asymmetric Homoaldol Reactions with Cyclohex-2-enylN,N-Diisopropylcarbamate: Kinetic Resolution, Elucidation of the Stereochemical Course and Applications in the Synthesis of Hexahydroisobenzofuran-4-(1H)-ones
Enantio-enriched cyclohex-2-enyl N,N-diisopropylcarbamate (5) is stereospecifically deprotonated by sec-butyllithium/(–)-sparteine (9) to form the configurationally stable lithium complex 7·9. A kinetic resolution of rac-5 by n-butyllithium/(–)-sparteine (9) yielded (R)-5 with up to 99 % ee. Electrophilic substitution with tin electrophiles proceeds in a anti-SE′ fashion as shown by chemical correlations. The synthesized allylstannanes 10 undergo a highly stereospecific TiCl4-mediated homoaldol reaction with various aldehydes, yielding syn-configured homoaldol products 12. These were transferred into all-cis-configured hexahydroisobenzofuran-4(1H)-ones 22 by BF3·OEt2-mediated reactions with…
The Effect of Incongruence Between CEO and Corporate Brand Personality on Financial Analysts’ Attitudes and Assessment of a Company’s Performance
This research assesses the role of two types of nonfinancial information in investor relations: The personality of the Chief Executive Officer (CEO) and the personality of the corporate brand. As both personalities determine the identity of a company and the relationship with its stakeholders, we investigate their relevance and the effect of incongruence between these two personalities on financial analysts. Eleven semistructured interviews were conducted to answer the theoretically derived research questions. Empirical findings show that both personalities are relevant to analysts and that perceived incongruence between these personalities can cause adverse effects. Company size, stage of …
Acidimetrische Titration von Mikrogramm-Mengen von Basen, speziell von biogenen Aminen, mit coulometrischer Reagenserzeugung in wasserarmen L�sungsmitteln
Amine von biochemischen Interesse werden in Mengen von 10–100 μg acidimetrisch mit coulometrischer Reagenserzeugung titriert, wobei Standardabweichungen von einigen Prozenten beobachtet werden. Als Elektrolyt dient Natriumperchlorat-haltiges Aceton, das bis zu 2% Wasser enthalten kann. Zur Verbesserung der Auflosung der Amine wird Milchsaure benutzt. Ein Zusatz von Quecksilberacetat sorgt dafur, das auch Aminhydrochloride bestimmt werden konnen.