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Department Chemie
Organische Chemie
Prof. Dr. Jan Paradies
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Frustrated Lewis Pairs

 A frustrated Lewis pair (FLP) consists of a Lewis acid and a Lewis base which do not quench their reactivities due to (mostly) steric and/or electronic reasons. This unquenched reactivity leads to the development of metal-free activations of molecular hydrogen (D. W. Stephan, Science, 2006).
We exploited this reactivity for the hydrogenation of olefins (Angew. Chem. 2012, Angew. Chem. 2014) and nitroolefins (Angew. Chem. 2013). The reactivity of FLPs can be adjusted to the application by the appropriate choice of the Lewis acid and Lewis base component (Chem. Sci. 2013). Furthermore our group is interested in mechanistic aspects of the hydrogen acitivation and the reactivity of FLPs in hydrogenations (Chem. Eur. J. 2015).

Multinuclear Transition Metal Complexes in Catalysis

Multinuclear complexes are ubiquitous in inorganic chemistry as well as catalysts for organic transformations. Especially Di- and trinuclear gold complexes are highly efficient catalysts for cycloisomerizations and addition reactions to double and triple bonds. Such catalysts often show superior reactivity and enantioselectivity compared to related mononuclear gold complexes. So far the reason for this increased efficiency has not yet been systematically analyzed, although dinuclear gold complexes are widely used in catalysis and cooperative activity has been reported for other multinuclear metal complexes. We have demonstrated that the kinetic analysis is a suitable tool to reveal cooperative effects in the amidation of aryl chlorides (Eur. J. Org. Chem. 2014) and in the gold-catalyzed hydroamidation (Eur. J. Inorg. Chem. 2012, Eur. J. Org. Chem. 2014). However, the origin of the non-additive rate enhancement and the role of the counter-ion are not yet clear and is currently invstigated in our group.

Carbon-Sulfur Cross Coupling

Chemical scientists have been inspired by natural product synthesis to develop highly sophisticated methodologies for organic transformations. Surprisingly, such tendency to develop methodologies for the efficient synthesis of organic materials can only be sparingly observed. However, the development of efficient methodologies for the synthesis of organic materials is of utmost importance. This lack of such synthetic methodology is addressed in the presented project by the efficient synthesis of sulfur-containing heteroacenes by modern transition metal catalysis. Sulfur-based anellated heteroacenes are semi-conductors, which find application in organic field-effect-transistors (OFET). The access to such structures is often limited by the use of highly toxic and/or moisture- and oxygen-sensitive sulfur reagents.
We developed a C–S cross coupling reaction using thiourea as easy-to-handle H2S-surrogate for the synthesis of diaryl sulfides, benzothiophenes and thienothiophenes (Org. Lett 2012). We further extended this methodology for the palladium-catalyzed two-step synthesis of dibenzo[d,d′]thieno[3,2-b;4,5-b′]dithiophene (DBTDT) and dithieno[3,2-b:2′,3′-d]thiophene (DTT) (Org. Lett 2014). Our interest is dedicated to the extension of these methodologies for the synthesis of larger sulfur-containing heteroacenes.

Group Leader

Prof. Dr. Jan Paradies

Organische Chemie - Arbeitskreis Paradies

Group Leader

Jan Paradies
+49 5251 60-5770
+49 5251 60-3245

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