P=C-N Systems: Potential of benzazaphospholes for transition metal complexes with non-classical P hybrid ligands, for bulky P-substituted heterocyclic phosphane ligands, complexes and catalysts and for benzazaphospholium salts as precursors of P,N-heteroc

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Reactivity studies of aromatically stabilized P=C-N heterocycles, specially of various N- and C-substituted 1,3-benzazaphospholes and related coplanar tetracyclic P=C-N-heterocycles, shall be carried out with the following objectives:- Synthesis and structural characterization of complexes of mono- and bidentate heterocyclic P=C-N-ligands and (P=C-N),P- or (P=C-N),N hybrid ligands with mono- and divalent transition metal ions as novel type of complexes for potential use in transition metal catalysis.- Development of a new synthesis strategy to mono- and bidentate bulky and electronrich P-tert-butyl substituted P,N heterocyclic phosphane ligands by controlled addition at the P=C-N structure group with emphasis to enantioselective P=C addition, induced by an asymmetric N-substituent. This shall lead to new asymmetric P,N ligands which might be useful for transition metal catalyzed enantioselective organic transformations. - Conversion of benzazaphospholes into N,P-dineopentyl-benzazaphospholium salts, exploration of their properties and synthesis potential for the access to novel P,N-heterocyclic carbene complexes. By isolation and structural characterization of such a complex we want to gain knowledge on the influence of the fixation of the two heteroatoms in a five-memebred ring on the properties of these carbenes. So far only acyclic representatives are known. Carbene complexes of various types have found extremely manifold applications in catalytic reactions.