Addition of a calcium hydride complex to diphenylacetylene gave a complex in which the stilbene dianion symmetrically bridges two Ca ions. DFT calculations discuss the effect of the metal stilbene coordination. The stilbene complex reacts as a base (with H) or an electron donor (with I) and catalyzes the reduction of diphenylacetylene.

A stereodivergent synthesis using inexpensive reagents, i.e., dibenzazepine and glucose-derived t-Bu-sulfinate diastereomers (R S )-6 or (S S )-6, affords respective S(O)-alkene hybrid ligands (S)-7 and (R)-7 on gram scales and in excellent optical purity (ee > 99%). Phenyl substitution of the dibenzoazepine backbone generates planar chirality to give epimerizationresistant (pS,R S )-10 diastereoisomer in high isomeric purity. Furthermore, the crystal structure of widely used sulfinate (R S )-6 is disclosed for the first time since its discovery a quarter of a century ago. Ligands 7 and 10 coordinate Rh(I) in a bidentate fashion through the S atoms and the alkene functions as evidenced by the crystal structures of complexes (R)-11 and (S N ,S S )-12. (R)-11 catalyzes the conjugate addition of arylboronic acids to enones with enantioselectivities of up to 77% ee. The reaction proceeds smoothly also under base-free conditions at 40 °C. The planar chirality in ligand (pS,R S )-10 is shown to override and invert the sense of chiral induction predicted by the configuration of the sulfur donor atom.

The efficient catalytic reduction of imines with phenylsilane is achieved by using the potassium, calcium and strontium based catalysts [(DMAT)K (THF)]∞, (DMAT)2Ca⋅(THF)2 and (DMAT)2Sr⋅(THF)2 (DMAT=2‐dimethylamino‐α‐trimethylsilylbenzyl). Eight different aldimines and the ketimine Ph2C=NPh could be successfully reduced by PhSiH3 at temperatures between 25–60 °C with catalyst loadings down to 2.5 mol %. Also, simple amides like KN(SiMe3)2 or Ae[N(SiMe3)2]2 (Ae=Ca, Sr, Ba) catalyze this reaction. Activities increase with metal size. For most substrates the activity increases along the row K

Deprotonation of phenyl-dibenzo[b,f]tropylidene 8 with LDA/t-BuOK followed by quenching with either diastereomers of inexpensive glucose-based t-Bu-sulfinates (R)-or (S)-11 affords a sulfoxidealkene hybrid ligand as diastereomeric pairs (S S ,S C )-9 / (S S ,R C )-10 and (R S ,R C )-9 / (R S ,S C )-10, respectively, which via chromatographic/recrystallization may be separated into the four isomers. The optically pure diastereomeric ligands (S S ,S C )-9 and (S S ,R C )-10 react with [RhCl(coe) 2 ] 2 to form the dinuclear complexes (R S ,S C )-11 and (R S ,R C )-12, respectively, in which the bidentate ligands coordinate the metal centers through the sulfur and alkene donor functions. These complexes catalyze the conjugate addition of arylboronic acids to cyclic Michael acceptors with enantioselectivities of up to 99% ee. DFT calculations show the preponderant influence of planar chirality of the ligand alkene function. The enantioselectivity switch observed between (R S ,S C )-11 and (R S ,R C )-12 is explained by the inverted cis-trans coordinations of the substrate molecules in catalytic steps.

Oxidative addition of 1.5 equiv of bromine or iodine to a Ir(I) sulfoxide pincer complex affords the corresponding Ir(IV) tris-bromido or tris-iodido complexes, respectively. The unprecedented trap-free reductive elimination of iodine from the Ir(IV)-iodido complex is induced by coordination of ligands or donor solvents. In the case of added I − , the isostructural tris-iodo Ir(III)-ate complex is quickly generated, which then can be readily reoxidized to the Ir(IV)-iodido complex with FcPF 6 or electrochemically. DFT calculations indicate an "inverted ligand field" in the Ir(IV) complexes and favor dinuclear pathways for the reductive elimination of iodine from the formal d 5 metal center.