| Summary: | AbstractThis thesis reports the independent synthesis of both enantiomers of P-chirogenic phosphine ligands and the building blocks thereof, which are suitable for parallel synthesis efforts and for the generation of more diverse libraries of P-chirogenic compound. The use of P-chirogenic phosphine boranes in transition metal-catalyzed reactions, such as palladium-catalyzed allylic alkylation and amination, is also described. Papers I and II describe the synthesis and evaluation of different chiral diamines in the enantioselective deprotonation of alkyl- and aryl-substituted prochiral phosphine boranes. Although (-)-sparteine ligated to sec-BuLi is reported to give high enantioselectivity in the deprotonation of prochiral phosphine-borane, this methodology suffers from the lack of availability of (+)-sparteine. We have shown that diamines derived from the quinolizidine alkaloid (-)-cytisine, which is extracted from the Golden Rain Tree (Laburnum anagyroides), are excellent substitutes for (+)-sparteine and thus facilitate the preparation of both enantiomers of a P-chirogenic phosphine via enantioselective deprotonation.The utility of P-chirogenic scaffolds obtained by desymmetrization is presented in Papers III, IV and V. A set of new P-chirogenic building blocks was synthesized via asymmetric deprotonation and utilized in the further syntheses of libraries of different P,N ligands or α-carboxyphosphine boranes. Applications of the phosphine boranes as pro-ligands in palladium-catalyzed reactions are also described.In Paper VI, a novel biocatalytic desymmetrization of prochiral phosphine-boranes mediated by lipase B of Candida antarctica is presented. Both enantiomers can be prepared with good to excellent enantioselectivity either through hydrolysis of a prochiral diacetate or via acylation of a prochiral diol.Finally, Paper VII describes a highly stereoselective and enantioselective Au(I)-catalyzed intermolecular olefin cyclopropanation. This reaction is based on an intermediate gold-carbenoid species, derived ...
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