Modular cyclodiphosph(V)azanes are synthesised and their affinity for chloride and actetate anions were compared to those of a bisaryl urea derivative (1). The diamidocyclodiphosph(V)azanes cis-[{ArNHP(O)(μ-tBu)}₂] [Ar=Ph (2) and Ar=m-(CF₃)₂Ph (3)] were synthesised by reaction of [{ClP(μ-NtBu)}₂] (4) with the respective anilines and subsequent oxidation with H₂O₂. Phosphazanes 2 and 3 were obtained as the cis isomers and were characterised by multinuclear NMR spectroscopy, FTIR spectroscopy, HRMS and single-crystal X-ray diffraction. The cyclodiphosphazanes 2 and 3 readily co-crystallise with donor solvents such as MeOH, EtOH and DMSO through bidentate hydrogen bonding, as shown in the X-ray analyses. Cyclodiphosphazane 3 showed a remarkably high affinity (log[K]=5.42) for chloride compared with the bisaryl urea derivative 1 (log[K]=4.25). The affinities for acetate (AcO⁻) are in the same range (3: log[K]=6.72, 1: log[K]=6.91). Cyclodiphosphazane 2, which does not contain CF₃ groups, exhibits weaker binding to chloride (log[K]=3.95) and acetate (log[K]=4.49). DFT computations and X-ray analyses indicate that a squaramide-like hydrogen-bond directionality and C_αH interactions account for the efficiency of 3 as an anion receptor. The C_αH groups stabilise the Z,Z-3 conformation, which is necessary for bidentate hydrogen bonding, as well as coordinating with the anion.

A series of bulky, modular, monodentate, fenchol-based phosphites has been employed in an intramolecular palladium-catalyzed alkyl-aryl cross-coupling reaction. This enantioselective α-arylation of N-(2-bromophenyl)-N-methyl-2-phenylpropanamide is accomplished with [Pd(C₃H₅)(BIFOP-X)(Cl)] as precatalysts, which are based on biphenyl-2,2′-bisfenchol phosphites (BIFOP-X, X=F, Cl, Br, etc.). The phosphorus fluoride BIFOP-F gives the highest enantioselectivity and good yields (64% ee, 88%). Lower selectivities and yields are found for BIFOP halides with heavier halogens (Cl: 74%, 47% ee, Br: 63%, 20% ee). NMR studies on catalyst complexes reveal two equilibrating diastereomeric complexes in equal proportions. In all cases, the phosphorus-halogen moiety remains intact, pointing to its remarkable stability, even in the presence of nucleophiles. The increasing enantioselectivity of the catalysts with the phosphorus halide ligands correlates with the rising electronegativity of the halide (bromine<chlorine<fluorine), as can be rationalized from structural parameters and DFT computations.

Two new classes of terpenol-based lithium phosphonates, i.e. phenylfenchyl phosphonates and 2,2′-biphenyldiylbis(terpenyl) phosphonates, are employed as umpolung catalysts for the enantioselective cross benzoin coupling. The structural characteristics of the phosphonates were investigated by means of X-ray, ³¹P-NMR analyses as well as DFT computations. The chiral lithium phosphonates were found to catalyze the cross benzoin coupling with enantioselectivities up to 54 % ee. For the phenylfenchyl phosphonates, the catalyst reactivities highly depend on the substituents in benzylic position. Modification of benzylic >CH₂ to >C(CF₃)₂ significantly increases the yield from 19 to 92 %. For phenylfenchyl phosphonate pre-catalysts, substitution of the benzylic >CH₂ group by >C(CF₃)₂ changes the sense of enantioselectivity from S- to the R-configured benzoin product.

New enantiopure pyridyl alcohols are efficiently accessible through few synthetic steps from commercially available terpenes, that is, (+)-fenchone, (−)-menthone and (−)-verbenone as well as 2,6-diphenylpyridine. These chelating pyridyl alcohols exhibit flexible pyridyl–phenylene axes, which give rise to P and M conformers. Alkylzincation of the hydroxy groups eliminates equilibria of the conformers and generates alkylzinc complexes with adjusted biaryl axes, as it is demonstrated by NMR studies. These alkylzinc catalysts perform well in the addition of dimethylzinc or diethylzinc to benzaldehyde with yields up to 99 % and ee’s up to 95 %. The adjusted pyridylphenylene conformations in the ligands now control enantioselectivities of the catalysts, which were also analysed by computations at the DFT level.

The CH functionalization of methane by means of direct CH borations with BH₃ or MeBH₂ is compared computationally (using the B3LYP/6-311⁺⁺G** method) to CH lithiations with LiH or LiMe as well as to other analogue C–metal (Be, Na, Mg, Al) formations. For the borations only, this internal electrophilic substitution at carbon (S_Ei) relies more on the electrophilicity of boron than on the basicity of the internal base Y, that is, H or Me. Such direct borations of methane are more favored for dehydrogenations than for dehydrocarbonations. Due to decreased electrophilicity, substituents at boron disfavor such borations. Hence, the BH₂ group appears to be most efficient for CH functionalizations by means of direct hydrocarbon borations.