Entrepreneurial behavior in social contexts: the role of families, teams and employees for entrepreneurial individuals

This dissertation consists of five studies that focus on different social contexts of entrepreneurial individuals and that analyze important cognitive or affective processes in these contexts. The dissertation comprises different stages of the entrepreneurial process and shows the social context’s importance in these stages. Chapter 2 represents the first step in the entrepreneurial process, the formation of entrepreneurial intentions. The influence of individuals’ families of origin contingent on national culture on these intentions is analyzed. Chapters 3, 4, and 5 focus on a team context and are based on a team experiment with an entrepreneurial decision making task. Chapter 3 analyzes the team’s decision quality based on information exchange, experimentally manipulated information uncertainty, and team metacognitive knowledge. In a next step, chapter 4 analyzes the members’ and the teams’ ability to assess their performance in the decision making task dependent on the level of relationship conflict experienced in the team. Chapter 5 focuses on the team members’ affective reactions to conflicts experienced in the team task contingent on team efficacy and information uncertainty. Finally, Chapter 6 concentrates on a further social context of entrepreneurial individuals, new venture employees. It analyzes how the employees’ perceptions of their supervisor’s entrepreneurial passion influence their commitment to the venture via their positive affect at work and goal clarity. This dissertation concludes with implications and suggestions for future research at the intersection of entrepreneurship and organizational behavior which will improve the understanding of entrepreneurial individuals and of the interdependencies with their social contexts

Divalent triazole‐linked carbohydrate mimetics: Synthesis by click chemistry and evaluation as selectin ligands

Starting from an enantiopure 3‐amino‐substituted pyran derivative, the synthesis of a series of divalent 1,2,3‐triazole‐linked carbohydrate mimetics is described. The preparation of the required 3‐azido‐substituted pyran proceeds smoothly by copper‐catalyzed diazo transfer. Using different conditions for the Huisgen‐Meldal‐Sharpless cycloaddition, this azide reacts with several diynes to furnish the desired divalent carbohydrate mimetics bearing rigid or flexible linker units. The in situ generation of the 3‐azidopyran in the presence of Cu/C as catalyst followed by the reaction with the alkyne allows a direct one‐pot transformation from the 3‐aminopyran to the desired click products. We also examined the Sakai‐Westermann method that transfers primary amines with the aid of α,α‐dichlorotosylhydrazones into 1,2,3‐triazoles. These copper‐free click conditions were applied for the first time to the preparation of a divalent compound. The O‐sulfation of the carbohydrate mimetics was achieved using the SO3‐DMF complex under careful 1H‐NMR control. Five polysulfated compounds could be obtained in pure form and these were tested by surface plasmon resonance spectroscopy as inhibitors of L‐selectin giving IC50 values between 45 nm and 50 µm

Quantification of the nucleophilic reactivity of nicotine

Rate and equilibrium constants of the reactions of nicotine and structurally related compounds with benzhydrylium ions have been determined UV-Vis spectroscopically using stopped-flow and laser-flash techniques. The pyridine nitrogen of nicotine was identified as the site of thermodynamically and kinetically controlled attack. Quantum chemical calculations showed that the introduction of a pyrid-3-yl moiety into the 2-position of N-methylpyrrolidine (to give nicotine) reduces the Lewis basicity of the pyrrolidine ring by 24kJmol(-1), whereas the analogous introduction of a phenyl ring decreases this quantity by only 11kJmol(-1)

Ammonium Pertechnetate in Mixtures of Trifluoromethanesulfonic Acid and Trifluoromethanesulfonic Anhydride

Ammonium pertechnetate reacts in mixtures of trifluoromethanesulfonic anhydride and trifluoromethanesulfonic acid under final formation of ammonium pentakis(trifluoromethanesulfonato)oxidotechnetate(V), (NH$_{4}$)$_{2}$ [TcO(OTf) $_{5}$]. The reaction proceeds only at exact concentrations and under the exclusion of air and moisture via pertechnetyl trifluoromethanesulfonate, [TcO$_{3}$(OTf)], and intermediate Tc$^{VI}$ species. $^{99}$Tc nuclear magnetic resonance (NMR) has been used to study the Tc$^{VII}$ compound and electron paramagnetic resonance (EPR), $^{99}$Tc NMR and X-ray absorption near-edge structure (XANES) experiments indicate the presence of the reduced technetium species. In moist air, (NH$_{4}$)2[TcO(OTf)5] slowly hydrolyses under formation of the tetrameric oxidotechnetate(V) (NH$_{4}$)$_{4}$ [{TcO(TcO$_{4}$)$_{4}$}$_{4}$] ⋅10 H$_{2}$O. Single-crystal X-ray crystallography was used to determine the solid-state structures. Additionally, UV/Vis absorption and IR spectra as well as quantum chemical calculations confirm the identity of the species

Breslow intermediates (aminoenols) and their keto tautomers: first gas‐phase characterization by IR ion spectroscopy

Breslow intermediates (BIs) are the crucial nucleophilic amino enol intermediates formed from electrophilic aldehydes in the course of N‐heterocyclic carbene (NHC) catalyzed Umpolung reactions. Both in organocatalytic and enzymatic Umpolung, the question whether the Breslow intermediate exists as the nucleophilic enol, or in the form of its electrophilic keto‐tautomer, is of utmost importance for its reactivity and function. We herein report the preparation of charge‐tagged Breslow intermediates/keto tautomers derived from three different types of NHCs (imidazolidin‐2‐ylidenes, 1,2,4‐triazolin‐5‐ylidenes, thiazolin‐2‐ylidenes) and aldehydes. An ammonium charge‐tag is introduced by either the aldehyde unit or the NHC. ESI‐MS IR‐Ion spectroscopy allowed for the unambiguous conclusion that in the gas‐phase, the imidazolidin‐2‐ylidene derived BI indeed exists as a diamino enol, while both 1,2,4‐triazolin‐5‐ylidenes and thiazolin‐2‐ylidenes give the keto‐tautomer. This result coincides with the tautomeric states observed for the BIs in solution (NMR) and in the crystalline state (XRD), and is in line with our earlier calculations on the energetics of BI keto‐enol equilibria

Iodine-Catalyzed Carbonyl-Alkyne Metathesis Reactions

The reaction between aldehydes or ketones and alkynes –the carbonyl-alkyne metathesis– constitutes a very useful strategy for the synthesis of ,-unsaturated carbonyls. We now demonstrate that iodine is a highly efficient catalyst for both the intra- and intermolecular metathesis reaction in very small concentrations (0.1–1 mol%). Our protocol outperforms other catalytic systems, is operationally very simple, cheap, metal-free, and tolerates a large variety of functional groups (e.g., –CN, –CO2Me, –Br, –OH) at very low catalyst loadings. We can furthermore show that iodine-catalyzed carbonyl-alkyne metatheses can be combined with other iodine-catalyzed reactions in one-pot procedures to afford larger and more complex molecular structures. Finally, our mechanistic studies indicate that the iodonium ion is the active catalyst under the reaction conditions