(1S,2S)-N,N′-Bis(o-(diphenylphosphino)benzylidene)cyclohexane-1,2-diamine and (1R,2R)-N,N′-Bis(o-(diphenylphosphino)benzylidene)cyclohexane-1,2-diamine

[174677-82-8] C44H40N2P2 (MW 658.75) InChI = 1S/C44H40N2P2/c1-5-21-37(22-6-1)47(38-23-7-2-8-24-38)43-31-17-13-19-35(43)33-45-41-29-15-16-30-42(41)46-34-36-20-14-18-32-44(36)48(39-25-9-3-10-26-39)40-27-11-4-12-28-40/h1-14,17-28,31-34,41-42H,15-16,29-30H2/b45-33+,46-34+/t41-,42-/m0/s1 InChIKey = GCUKRENTSKVSIL-DYDPWSPUSA-N [174758-61-3] C44H40N2P2 (MW 658.75) InChI = 1S/C44H40N2P2/c1-5-21-37(22-6-1)47(38-23-7-2-8-24-38)43-31-17-13-19-35(43)33-45-41-29-15-16-30-42(41)46-34-36-20-14-18-32-44(36)48(39-25-9-3-10-26-39)40-27-11-4-12-28-40/h1-14,17-28,31-34,41-42H,15-16,29-30H2/b45-33+,46-34+/t41-,42-/m1/s1 InChIKey = GCUKRENTSKVSIL-MSBFTLGYSA-N (chiral ligand for transition metal-catalyzed asymmetric reactions, including ketone and imine reductions, epoxidation of alkenes, cyclopropanation of olefins, and Diels–Alder reactions of unsaturated β-keto esters)1-3 Alternate Names: (S,S)-C6P2N2, (R,R)-C6P2N2; (S,S)-N,N′-bis[o-(diphenylphosphino)benzylidene]-1,2-diiminocyclohexane; (R,R)-N,N′-bis[o-(diphenylphosphino)benzylidene]-1,2-diiminocyclohexane; N,N′-bis[o-(diphenylphosphino)benzylidene]-lS,2S-diiminocyclohexane; N,N′-bis[o-(diphenylphosphino)benzylidene]-lR,2R-diiminocyclohexane. Physical Data: yellow or pale orange solid, mp 60–62 °C, (c 1, CH2Cl2). Solubility: soluble in chlorinated solvents as dichloromethane, chloroform, as well as acetone, warm EtOH, insoluble hexane, and water. Analysis of Reagent Purity: 1H NMR (500 MHz, CDCl3): δ 8.69 (d, 2 H, J = 4.0 Hz), 6.79–7.74 (m, 28 H), 3.11 (m, 2 H), 1.65 (d, 2 H, J = 6.0 Hz), 1.45 (m, 2 H), 1.38 (d, 2 H, J = 7.8 Hz), 1.26 (m, 2 H); 31P NMR (500 MHz, CDCl3): δ −12.98. Preparative Methods: The ligands can be prepared by the condensation of o-(diphenylphosphino)benzaldehyde with (S,S)-/(R,R)-1,2-diaminocyclohexane in CH2Cl2 using anhydrous Na2SO4 as a dehydrating agent.4 An alternative procedure has been developed whereby (S,S)-/(R,R)-1,2-diaminocyclohexane l-tartrate salt is coupled to a mixture of potassium carbonate and o-(diphenylphosphino)benzaldehyde in refluxing water/ethanol mixture.5 Handling, Storage, and Precautions: stable to air and moisture; incompatible with strong acid or oxidants; stored in refrigerator; generally considered low mammalian toxicity, however thorough toxicity studies have not been performed; skin/eye contact should be avoided.