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.

10-Phenyl-5H-dibenz[b,f ]azepine ( 5) is synthesized by Suzuki cross coupling of the protected bromo alkene 4 with PhB(OH) 2 . 5 reacts with PCl 3 to afford the dichlorophosphanyl-azepine 6 in >90% yield. Alkylation of 6 with 1 equiv of t-BuMgBr leads, after recrystallization in Et 2 O, to the diastereomerically enriched (dr > 98:2) chloride rac-7, which the crystal structure reveals to be the (pS,R P )/ (pR,S P ) pair. The fact that rac-7 crystallizes in the Sohncke space group P2 1 2 1 2 1 opens up the possibility of a mechanical separation of the enantiomers. Methylation of rac-7 is perfectly stereoselective with inversion of configuration at the P atom to yield the new ligand rac-8 as the (R,R)/(S,S) pair. The corresponding BH 3protected diastereomer rac-9 (i.e., the (R,S)/(S,R) pair), is isolated after flash column chromatography in 73% yield. Compounds 5−9 are accessible in multigram quantities. X-ray crystal structures of Ru(II) complexes demonstrate the ambidentate nature of ligand rac-8: Complex 10 is exclusively P-coordinated, while in complex 11 two ligands bind Ru through their P donors and stabilize the 14-electron metal center with a double agostic interaction. In complex 12, the ligand coordinates in a κP,η 2 -alkene bidentate fashion.

Multigram quantities of the optically pure amino−bis-sulfoxide ligand (S,S)-bis(4-tert-butyl-2-(ptolylsulfinyl) phenyl)amine ((S,S)-3) are accessible by in situ lithiation of bis(2-bromo-4-tert-butylphenyl)amine (1) followed by a nucleophilic displacement reaction with Andersen's sulfinate 2. Deprotonation of (S,S)-3 with MgPh2 yields the magnesium amido−bis-sulfoxide salt (S,S)-4 quantitatively. AbstractMulti-gram quantities of the optically pure amino-bissulfoxide ligand (S,S)-bis(4-tert-butyl-2-(ptolylsulfinyl)phenyl)amine ((S,S)-3) are accessible by in situ lithiation of bis-(2-bromo-4-tertbutylphenyl)amine 1 followed by a nucleophilic displacement reaction with Andersen's sulfinate 2.

The reactions of rac- and (S,S)-trans-9,10-dihydro-9,10-ethanoanthracene-11,12-diamine (ANDEN) with PClPh2 in the presence of NEt3 yield the chiral amino-phosphine ligands rac-6 and (S,S)-6, respectively, on multi-gram scales. Both forms of 6 react quantitatively with MgPh2 to afford the C2-symmetric, N-bound Mg amidophosphine complexes rac-7 and (S,S)-7. The former crystallizes as a racemic conglomerate, which is a rare occurrence. Mixing (S,S)- or rac-6 with [IrCl(COE)2]2 leads in both cases to the homochiral dinuclear chloro-bridged P-ligated aminophosphine iridium complexes (S,S,S,S)-9 and rac-9 in excellent yields. X-ray quality single crystals only grow as the racemic compound (or 'true racemate') rac-9 thanks to its lowered solubility. In the coordinating solvent CH3CN, rac-9 transforms in high yield into mononuclear Ir-complex rac-10. The crystal structures of compounds rac-6, (S,S)-7, rac-9, and rac-10 reveal the ambidentate nature of the P-N function: amide-coordination in the Mg-complex (S,S)-7 and P-chelation of the softer Ir(i) centres in complexes rac-9 and rac-10. Furthermore, the crystal structures show flexible, symmetry lowering seven-membered P-chelate rings in the Ir complexes and a surprising amount of deformation within the ANDEN backbone. The simulation of this deformation by DFT and SCF calculations indicates low energy barriers. (S,S)-7 and (S,S,S,S)-9 catalyze the intra- and intermolecular hydroamination of alkenes, respectively: 5 mol% of (S,S)-7 affords 2-methyl-4,4'-diphenylcyclopentyl amine quantitatively (7% ee), and 2.5 mol% of (S,S,S,S)-9 in the presence of 5.0 mol% co-catalyst (LDA, PhLi, or MgPh2) gives exo-(2-arylamino)bornanes in up to 68% yield and up to 16% ee.

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.