Sequential Addition of Phosphine to Alkynes for the Selective. Synthesis of 1,2-Diphosphinoethanes under Catalysis. Well-Defined

Supporting Information for the Paper Sequential Addition of Phosphine to Alkynes for the Selective Synthesis of 1,2-Diphosphinoethanes under Catalysis. Well-Defined NHC-Copper Phosphides vs in Situ CuCl 2 /NHC Catalyst Jia Yuan, Lizhao Zhu, Jianying Zhang, Jianfeng Li, and Chunming Cui*,, State Key Laboratory of Elemento-Organic Chemistry, Nankai University Collaborative Innovation Center of Chemical Science and Engineering Tianjin 300071, People s Republic of China E-mail: cmcui@nankai.edu.cn General Considerations....S2 Procedures for the synthesis of 1, 2 and 4...S2 Typical procedures for catalytic double hydrophosphination of alkynes.s3 X-ray crystallographic data...s3 Computational details..... S4 Monitoring the reaction of 2 with phenylacetylene by 1 H NMR and 31 P NMR...S7 Monitoring the reaction of 4 with HPPh 2 by 1 H NMR and 31 P NMR.S8 1 H, 13 C and 31 P NMR spectra for all products...s9 References...S36 S1

Experimental Section General Considerations. All manipulations of air-sensitive materials were carried out under an atmosphere of dry argon by using modified Schlenk line and glovebox techniques. Alkenes and copper salts were purchased from Alfa-Aesar and J&K Scientific Ltd. All solvents were distilled from appropriate drying agents under argon before use. The 1 H, 13 C, and 31 P NMR spectroscopic data were recorded on Bruker Mercury Plus 400 MHz NMR spectrometers. Chemical shifts (δ) for 1 H and 13 C are referenced to internal solvent resonances and reported relative to SiMe 4. Chemical shifts for 31 P are reported relative to an external 85% H 3 PO 4 standard. Elemental analysis was carried out on an Elemental Vario EL analyzer. High resolution mass analysis is performed on Varian 7.0T Fourier-transform mass spectrometry (FTMS) with ESI resource. The N-heterocyclic carbenes, 1,3-diisopropyl-4,5-dimethyl-imidazol-2-yidene (I i Pr), 1,3-di(tert-butyl)imidazol-2-ylidene (I t Bu), 1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene (IDipp) and IDippCuPPh 2 were synthesized according to the published procedures. [1] Synthesis of [(I i Pr)Cu(PPh 2 )] 3 (1). Method A. To a solution of 1,3-diisopropyl-4,5-dimethyl-imidazol-2-yidene (I i Pr) (720 mg, 4.0 mmol) in toluene (10 ml) was added CuCl 2 (134 mg, 1.0 mmol ) and Ph 2 PH (558 mg, 3.0 mmol). The mixture was stirred at 110 ºC for 1 h. The solution was cooled to room temperature and filtered. The solvent of eluate was concentrated to 1 ml and added hexane (10 ml) to give yellow solid of 1 (200 mg, 47%). Method B. To a solution of 1,3-diisopropyl-4,5-dimethyl-imidazol-2-yidene (I i Pr) (360 mg, 2.0 mmol) in toluene (10 ml) was added CuCl (99 mg, 1.0 mmol ) and Ph 2 PH (186 mg, 1.0 mmol). The mixture was stirred at 110 ºC for 1 h. The solution was cooled to room temperature and filtered. The solvent of eluate was removed under reduced pressure. The residue was washed with hexane to give yellow solid of 1 (292 mg, 68%). Mp > 200 C. 1 H NMR (400 MHz, C 6 D 6 ): δ 7.88 (s, 12 H, Ar), 7.09 (t, J = 7.3 Hz, 12 H, Ar), 6.96 (t, J = 7.0 Hz, 6 H, Ar), 4.64 4.71 (m, 6 H, CHMe 2 ), 1.59 (s, 18 H, Me), 1.17 (d, J = 6.8 Hz, 36 H, CHMe 2 ). 13 C NMR (101 MHz, C 6 D 6 ): δ 188.5 (s, carbene C), 150.0 (s, Ar), 134.2 (s, Ar), 127.9 (s, Ar), 127.7 (s, Ar), 127.5 (s, Ar), 126.9 (s, Ar), 122.9 (s, Ar), 122.7 (s, imid-c), 52.4 (s, CHMe 2 ), 22.3 (s, Me), 9.5 (s, CHMe 2 ). 31 P NMR (162 MHz, C 6 D 6 ): δ -35.6 (s). Anal. Calcd for C 69 H 90 Cu 3 N 6 P 3 : C, 64.39; H, 7.05; N, 6.53. Found: C, 64.33; H, 7.02; N, 6.51. Synthesis of [(I t Bu)Cu(PPh 2 )] 3 (2). Method A. To a solution of N,N-di(tert-butyl)imidazol-2-ylidene (I t Bu) (720 mg, 4.0 mmol) in toluene (10 ml) was added CuCl 2 (134 mg, 1.0 mmol ) and Ph 2 PH (558 mg, 3.0 mmol). The mixture was stirred at 110 ºC for 1 h. The solution was cooled to room temperature and filtered. The solvent of eluate was concentrated to 1 ml and added hexane (10 ml) to give yellow solid of 2 (306 mg, 72%). Method B. To a solution of N,N-di(tert-butyl)imidazol-2-ylidene (I t Bu) (360 mg, 2.0 mmol) in toluene (10 ml) was added CuCl (99 mg, 1.0 mmol ) and Ph 2 PH (186 mg, 1.0 mmol). The mixture was stirred at 110 ºC for 1 h. The solution was cooled to room temperature and filtered. The solvent of eluate was removed under reduced pressure. The residue was washed with hexane to give yellow solid of 2 (365 mg, 85%). Mp > 200 C. 1 H NMR (400 MHz, C 6 D 6 ): δ 7.69 (br, 12 H, Ar), 6.99 7.09 (m, 18 H, Ar), 6.60 (s, 6 H, CH), 1.38 (s, 54 H, CMe 3 ). 13 C NMR (101 MHz, C 6 D 6 ): δ 188.2 (s, carbene C), 149.1 (s, Ar), 136.1 (s, Ar), 129.0 (s, Ar), 128.2 (s, Ar), 126.5 (s, Ar), 123.4 (s, Ar), 116.4 (s, imid-c), 56.4 (s, CMe 3 ), 31.0 (s, CMe 3 ). 31 P NMR (162 MHz, C 6 D 6 ): δ -30.4 (s). Anal. Calcd for C 69 H 90 Cu 3 N 6 P 3 : C, 64.39; H, 7.05; N, 6.53. Found: C, 64.28; H, 7.03; N, 6.55. S2

Synthesis of (I t Bu)Cu(CCPh) (4). Method A. To a solution of 1,3-di(tert-butyl)imidazol-2-ylidene (I t Bu) (720 mg, 4.0 mmol) in toluene (10 ml) was added CuCl 2 (134 mg, 1.0 mmol ) and phenylacetylene (306 mg, 3.0 mmol). The mixture was stirred at 60 ºC for 1 h. It was cooled to room temperature and filtered. The filtrate was concentrated to 1 ml and added hexane (10 ml) to give white solid of 4 (259 mg, 75%). Method B. To a solution of I t Bu (360 mg, 2.0 mmol) in toluene (10 ml) was added CuCl (99 mg, 1.0 mmol ) and phenylacetylene (102 mg, 1.0 mmol). The mixture was stirred at 60 ºC for 1 h. The solution was cooled to room temperature and filtered. The solvent of eluate was removed under reduced pressure. The residue was washed with hexane to give white solid of 4 (283 mg, 82%). Mp: 151-152 C. 1 H NMR (400 MHz, C 6 D 6 ): δ 7.78 (d, J = 7.2 Hz, 2 H, Ar), 7.03 (t, J = 7.6 Hz, 2 H, Ar), 6.92 (t, J = 7.4 Hz, 1 H, Ar), 6.46 (s, 2 H, CH), 1.43 (s, 18 H, CMe 3 ). 13 C NMR (101 MHz, C 6 D 6 ): δ 176.5 (s, carbene C), 131.9 (s, Ar), 129.5 (s, Ar), 124.8 (s, imid-c), 122.9 (s, CuC CPh), 116.0 (s, Ar), 106.8 (s, C CPh), 57.3 (s, CMe 3 ), 31.6 (s, CMe 3 ). Anal. Calcd for C 19 H 25 CuN 2 : C, 66.15; H, 7.31; N, 8.12. Found: C, 66.23; H, 7.29; N, 8.09. Typical procedures for catalytic double hydrophosphination of alkynes. To a round bottom flask, diphenylphosphine (2 mmol), alkyne (1 mmol), I t Bu (0.05 mmol, 5 mmol%) and CuCl 2 (0.0125mmol, 1.25 mol%) were added under argon. The mixture was stirred for a certain time at 110 ºC. After removal of the volatile materials under reduced pressure, the residue was solved in toluene (10 ml). It was filtered and the solvent of eluate was removed under reduced pressure. The residue was washed with hexane to give the 1,2-bisphosphinoethane derivatives as a white powder. For the oxidation process, H 2 O 2 (30 %, 1 ml) was added to the mixture at room temperature. It was stirred for 1 h. The product was extracted with dichloromethane and dried over MgSO 4. After the solvent was removed, the crude product was purified by chromatograph on silica gel (n-hexane /acetone/dichloromethane). X-ray Structural Determination. The X-ray date were collected on a Rigaku Saturn CCD diffractometer using graphite-monochromated Mo Kα radiation (λ = 0.71073 Å) at 113 K. The structure was solved by direct methods (SHELXS-97) [2] and refined by full-matrix least squares on F 2. All non-hydrogen atoms were refined anisotropically and hydrogen atoms by a riding model (SHELXL-97). [3] The crystal data and structural refinements details are listed in Table S1. CCDC 1445745 (2) contains the supplementary crystallographic data for this paper. This data can be obtained free of charge from The Cambridge Crystallographic Data Centre via www.ccdc.cam.ac.uk/data_request/cif. S3

Table S1. Crystal Data and Summary of X-ray Data Collection for 2 2 formula C 69 H 90 Cu 3 N 6 P 3 fw 1287.04 T (K) 113(2) space group P21/n crystal system monoclinic a (Å) 26.862(3) b (Å) 22.2816(19) c (Å) 27.235(3) α (deg.) 90 β (deg.) 116.826(2) γ (deg.) 90 V (Å 3 ) 14547(3) Z 8 d calcd. (g/cm 3 ) 1.175 F(000) 5424.0 GOF 0.990 R 1 (I > 2σ (I)) 0.0597 wr 2 (all data) 0.1817 Computational Details. All calculations were performed using the Gaussian 03 suite of programs, revision C. 02.S7. [4] The geometries and harmonic vibration frequency of intermediates A-D were optimized in DFT method with B3lypmethod and 6-31G* basis set. Single point energies were calculated with the large M06/6-311+G(d,p) set. Figure S1. Optimized structures (distances in Å and angles in deg) of complex 4: C35 C36 1.23088, Cu34 C35 1.82620, C33 Cu34 1.87926, C36 C37 1.42538; C36 C35 Cu34 164.96204, C33 Cu34 C35 179.28872. S4

Figure S2. Optimized structures (distances in Å and angles in deg) of intermediate A: Cu34 C37 1.89855, C33 Cu34 1.94506, Cu34 P35 2.27244, C37 C38 1.23347, P35 H36 1.41607; C33 Cu34 P35 127.29600, C33 Cu34 C37 127.34563, P35 Cu34 C37 105.23756, Cu34 P35 H36 109.37496. Figure S3. Optimized structures (distances in Å and angles in deg) of intermediate B: C58 C70 1.26557, Cu34 C58 1.97710, Cu34 C70 1.91890, C33 Cu34 1.95274, Cu34 P35 2.35679; C70 Cu34 C58 37.87437, C58 Cu34 P35 131.54679, C70 Cu34 P35 93.68226, C58 S5

Cu34 C33 112.61701, C70 Cu34 C33 150.45493, C33 Cu34 P35 115.83542. Figure S4. Optimized structures (distances in Å and angles in deg) of intermediate C: C35 C36 1.35269, Cu34 C35 1.89151, C33 Cu34 1.88966, C36 P60 1.84962; C36 C35 Cu34 122.27146, C35 Cu34 C33 177.23411, Cu34 C35 C38 116.73455, P60 C36 C35 126.59104. Figure S5. Optimized structures (distances in Å and angles in deg) of intermediate D: C58 C59 1.35437, Cu34 C58 1.90165, C33 Cu34 1.89698, C59 P35 1.83362; Cu34 C58 C59 124.90787, C33 Cu34 C58 175.21640, C34 C58 C61 117.89400, C58 C59 P35 122.65812. S6

Figure S6. Monitoring the reaction of 2 with phenylacetylene by the 1 H NMR (top) and 31 P NMR (bottom) in C 6 D 6 in an NMR tube. Reaction conditions: phenylacetylene (0.05 mmol, 5.1 mg) and complex 2 (0.0167 mmol, 21.5 mg) in C 6 D 6 (0.4 ml). S7

E-product Z-product [(I t Bu)Cu(PPh 2 )] 3 (I t Bu)Cu(CCPh) + HPPh 2 RT, 2 h (I t Bu)Cu(CCPh) + HPPh 2 RT, 30 min HPPh 2 Figure S7. Monitoring the reaction of 4 with HPPh 2 by the 1 H NMR (top) and 31 P NMR (bottom) in C 6 D 6 in an NMR tube. Reaction conditions: Ph 2 PH (0.05 mmol, 9.3 mg) and complex 4 (0.05 mmol, 17.3 mg) in C 6 D 6 (0.4 ml). S8

(1-phenylethane-1,2-diyl)bis(diphenylphosphine). [5] 1 H NMR (400 MHz, CDCl 3 ): δ 7.29 7.46 (m, 11 H, Ar), 7.08 7.19 (m, 10 H, Ar), 6.99 7.03 (m, 2 H, Ar), 6.84 (t, J = 7.2 Hz, 2 H, Ar), 3.26 3.33 (m, 1 H, CH), 2.43 2.59 (m, 2 H, CH 2 ). 13 C NMR (101 MHz, CDCl 3 ): δ 140.3 (d, J CP = 3.5 Hz, Ar), 140.2 (d, J CP = 3.5 Hz, Ar), 139.1 (d, J CP = 13.6 Hz, Ar), 137.6 (d, J CP = 16.0 Hz, Ar), 136.8 (d, J CP = 15.8 Hz, Ar), 135.9 (d, J CP = 15.6 Hz, Ar), 134.3 (d, J CP = 6.7 Hz, Ar), 134.1 (d, J CP = 6.7 Hz, Ar), 132.9 (d, J CP = 17.7 Hz, Ar), 131.8 (d, J CP = 17.4 Hz, Ar), 130.8 (d, J CP = 9.7 Hz, Ar). 129.3 (d, J CP = 5.1 Hz, Ar), 129.3 (d, J CP = 5.2 Hz, Ar), 128.6 (d, J CP = 7.3 Hz, Ar), 128.5 (d, J CP = 7.4 Hz, Ar), 128.2 (d, J CP = 6.5 Hz, Ar), 128.1 (d, J CP = 5.8 Hz, Ar), 127.9 (s, Ar), 127.7 (d, J CP = 6.6 Hz, Ar), 126.5 (d, J CP = 2.3 Hz, Ar), 41.5 (t, J CP = 14.5 Hz, CH), 32.7 (dd, J CP = 21.3, J CP = 15.6 Hz, CH 2 ). 31 P NMR (162 MHz, CDCl 3 ): δ 3.0 (d, J PP = 17.6 Hz, PCH), -21.9 (d, J PP = 17.4 Hz, PCH 2 ). (1-(p-tolyl)ethane-1,2-diyl)bis(diphenylphosphine). [6] 1 H NMR (400 MHz, CDCl 3 ): δ 7.27 7.43 (m, 11 H, Ar), 7.00 7.18 (m, 11 H, Ar), 6.87 (t, J = 7.0 Hz, 2 H, Ar), 3.23 3.30 (m, 1 H, CH), 2.41 2.54 (m, 2 H, CH 2 ), 2.27 (s, 3 H, CH 3 ). 13 C NMR (101 MHz, CDCl 3 ): δ 139.3 (d, J CP = 13.6 Hz, Ar), 137.5 (d, J CP = 16.0 Hz, Ar), 137.1 (m, Ar), 136.1 (d, J CP = 15.7 Hz, Ar), 136.0 (d, J CP = 2.4 Hz, Ar), 134.3 (d, J CP = 3.4 Hz, Ar), 134.1 (d, J CP = 3.5 Hz, Ar), 132.9 (d, J CP = 17.6 Hz, Ar), 131.7 (d, J CP = 17.3 Hz, Ar), 129.2 (d, J CP = 5.5 Hz, Ar), 129.1 (d, J CP = 7.2 Hz, Ar), 129.0 (s, Ar), 128.5 (s, Ar), 128.5 (s, Ar), 128.4 (s, Ar).128.1 (s, Ar), 128.0 (s, Ar), 127.7 (s, Ar), 127.7 (s, Ar), 127.6 (s, Ar). 40.9 (t, J CP = 14.4 Hz, CH), 32.8 (dd, J CP = 21.2, J CP = 14.9 Hz, CH 2 ), 21.1 (s, CH 3, PCH 2 ). 31 P NMR (162 MHz, CDCl 3 ): δ 2.4 (d, J PP = 17.1 Hz, PCH), -22.2 (d, J PP = 17.2 Hz, PCH 2 ). (1-(4-methoxyphenyl)ethane-1,2-diyl)bis(diphenylphosphine). [6] 1 H NMR (400 MHz, CDCl 3 ): δ 7.28 7.44 (m, 10 H, Ar), 7.00 7.19 (m, 10 H, Ar), 6.86 (t, J = 7.2 Hz, 2 H, Ar), 6.73 (d, J = 8.5 Hz, 2 H, Ar), 3.76 (s, 3 H, OCH 3 ), 3.21 3.29 (m, 1 H, CH), 2.41 2.53 (m, 2 H, CH 2 ). 13 C NMR (101 MHz, CDCl 3 ): δ 158.1 (d, J CP = 2.1 Hz, Ar), 139.2 (d, J CP = 13.4 Hz, Ar), 137.6 (d, J CP = 15.8 Hz, Ar), 137.0 (d, J CP = 15.6 Hz, Ar), 136.0 (d, J CP = 15.6 Hz, Ar), 134.2 (d, J CP = 20.3 Hz, Ar), 132.9 (d, J CP = 17.5 Hz, Ar), 132.2 (dd, J CP = 8.6, J CP = 3.4 Hz, Ar), 131.8 (d, J CP = 17.4 Hz, Ar), 130.2 (d, J CP = 7.1 Hz, Ar), 129.2 (d, J CP = 7.3 Hz, Ar), 128.5 (d, J CP = 7.6 Hz, Ar), 128.4 (d, J CP = 7.7 Hz, Ar), 128.1 (s, Ar), 128.1 (s, Ar), 127.8 (s, Ar), 127.7 (d, J CP = 6.6 Hz, Ar), 113.7 (s, Ar), 55.1 (s, OCH 3 ), 40.6 (t, J CP = 14.3 Hz, CH), 32.9 (dd, J CP = 22.0, J CP = 15.0 Hz, CH 2 ). 31 P NMR (162 MHz, CDCl 3 ) δ 2.3 (d, J PP = 17.1 Hz, PCH), -22.0 (d, J PP = 17.2 Hz, PCH 2 ). S9

4-(1,2-bis(diphenylphosphino)ethyl)-N,N-dimethylaniline. [6] 1 H NMR (400 MHz, CDCl 3 ): δ 7.27 7.42 (m, 11 H, Ar), 7.18 (d, J = 3.5 Hz, 4 H, Ar), 6.96 7.11 (m, 5 H, Ar), 6.87 (t, J = 7.5 Hz, 1 H, Ar), 6.59 (d, J = 8.6 Hz, 2 H, Ar), 3.17 3.25 (m, 1 H, CH), 2.89 (s, 6 H, NMe 2 ), 2.39 2.52 (m, 2 H, CH 2 ). 13 C NMR (101 MHz, CDCl 3 ): δ 149.3 (s, Ar), 139.6 (d, J CP = 14.0 Hz, Ar), 137.8 (d, J CP = 16.4 Hz, Ar), 137.5 (d, J CP = 15.6 Hz, Ar), 136.5 (d, J CP = 16.3 Hz, Ar), 134.4 (d, J CP = 5.4 Hz, Ar), 134.2 (d, J CP = 5.4 Hz, Ar), 132.9 (d, J CP = 17.2 Hz, Ar), 131.8 (d, J CP = 17.2 Hz, Ar), 129.9 (d, J CP = 6.9 Hz, Ar), 129.1 (d, J CP = 5.5 Hz, Ar), 128.5 (s, Ar), 128.4 (s, Ar), 128.3 (s, Ar), 128.0 (d, J CP = 5.7 Hz, Ar), 127.9 (s, Ar), 127.6 (d, J CP = 3.1 Hz, Ar), 127.6 (s, Ar), 112.6 (s, Ar), 40.7 (s, NMe 2 ), 40.3 (t, J CP = 14.1 Hz, CH), 33.0 (dd, J CP = 22.2, J CP = 14.5 Hz, CH 2 ). 31 P NMR (162 MHz, CDCl 3 ): δ 1.7 (d, J PP = 17.0 Hz, PCH), -22.0 (d, J PP = 16.9 Hz, PCH 2 ). (1-(4-(tert-butyl)phenyl)ethane-1,2-diyl)bis(diphenylphosphine). [6] 1 H NMR (400 MHz, CDCl 3 ): δ 7.28 7.42 (m, 11 H, Ar), 7.15 7.19 (m, 6 H, Ar), 6.95 7.09 (m, 5 H, Ar), 6.76 (t, J = 7.0 Hz, 2 H, Ar), 3.26 3.32 (m, 1 H, CH), 2.40 2.62 (m, 2 H, CH 2 ), 1.27 (s, 9 H, CMe 3 ). 13 C NMR (101 MHz, CDCl 3 ): δ 149.2 (d, J CP = 2.2 Hz, Ar), 139.1 (d, J CP = 13.5 Hz, Ar), 137.9 (d, J CP = 15.9 Hz, Ar), 137.2 (d, J CP = 16.0 Hz, Ar), 136.9 (m, Ar), 136.0 (d, J CP = 15.8 Hz, Ar), 134.3 (d, J CP = 10.0 Hz, Ar), 134.1 (d, J CP = 9.8 Hz, Ar), 132.8 (d, J CP = 17.3 Hz, Ar), 131.9 (d, J CP = 17.5 Hz, Ar), 129.2 (d, J CP = 12.5 Hz, Ar), 128.8 (d, J CP = 7.0 Hz, Ar), 128.5 (d, J CP = 7.4 Hz, Ar), 128.4 (d, J CP = 7.3 Hz, Ar), 128.1 (d, J CP = 5.7 Hz, Ar), 127.9 (d, J CP = 12.1 Hz, Ar), 127.5 (d, J CP = 6.3 Hz, Ar), 125.1 (s, Ar), 41.1 (t, J CP = 15.0 Hz, CH), 34.3 (s, CMe 3 ), 32. 6 (dd, J CP = 21.8, J CP = 15.4 Hz, CH 2 ), 31.4 (s, CMe 3 ). 31 P NMR (162 MHz, CDCl 3 ): δ 3.1 (d, J PP = 18.5 Hz, PCH), -21.2 (d, J PP = 18.5 Hz, PCH 2 ). (1-(4-fluorophenyl)ethane-1,2-diyl)bis(diphenylphosphine). [6] 1 H NMR (400 MHz, CDCl 3 ): δ 7.27 7.46 (m, 10 H, Ar), 7.00 7.21 (m, 10 H, Ar), 6.83 6.88 (m, 4 H, Ar), 3.24 3.34 (m, 1 H, CH), 2.47 2.51 (m, 2 H, CH 2 ). 13 C NMR (101 MHz, CDCl 3 ): δ 161.4 (d, J CF = 247.5 Hz, Ar), 138.8 (d, J CP = 13.2 Hz, Ar), 137.4 (d, J CP = 15.6 Hz, Ar), 136.6 (d, J CP = 15.8 Hz, Ar), 136.0 (m, Ar), 135.6 (d, J CP = 15.4 Hz, Ar), 134.1 (d, J CP = 20.4 Hz, Ar), 132.9 (d, J CP = 18.0 Hz, Ar), 131.9 (d, J CP = 17.6 Hz, Ar), 130.6 (t, J CP = 7.5 Hz, Ar), 129.3 (d, J CP = 11.9 Hz, Ar), 128.6 (d, J CP = 7.3 Hz, Ar), 128.5 (d, J CP = 7.3 Hz, Ar), 128.4 (s, Ar), 128.2 (d, J CP = 5.9 Hz, Ar), 128.0 (s, Ar), 127.8 (d, J CP = 6.7 Hz, Ar), 115.1 (d, J CF = 21.3 Hz, Ar), 40.9 (t, J CP = 14.7 Hz, CH), 32.7 (dd, J CP = 21.6, J CP = 15.6 Hz, CH 2 ). 31 P NMR (162 MHz, CDCl 3 ): δ 3.0 (d, J PP = 17.0 Hz, PCH), -21.7 (d, J PP = 17.2 Hz, PCH 2 ). S10

(1-(4-chlorophenyl)ethane-1,2-diyl)bis(diphenylphosphine). 1 H NMR (400 MHz, CDCl 3 ): δ 7.27 7.43 (m, 10 H, Ar), 7.10 7.20 (m, 8 H, Ar), 6.98 7.06 (m, 4 H, Ar), 6.88 (t, J = 7.5 Hz, 2 H, Ar), 3.26 3.33 (m, 1 H, CH), 2.48 (t, J = 6.6 Hz, 2 H, CH 2 ). 13 C NMR (101 MHz, CDCl 3 ): δ 138.9 (dd, J CP = 8.7, J CP = 3.4 Hz, Ar), 138.7 (d, J CP = 13.1 Hz, Ar), 137.3 (d, J CP = 15.5 Hz, Ar), 136.4 (d, J CP = 15.6 Hz, Ar), 135.5 (d, J CP = 15.6 Hz, Ar), 134.0 (d, J CP = 20.4 Hz, Ar), 132.9 (d, J CP = 18.1 Hz, Ar), 132.1 (d, J CP = 3.0 Hz, Ar), 131.9 (d, J CP = 17.7 Hz, Ar), 130.5 (d, J CP = 7.1 Hz, Ar), 129.4 (d, J CP = 14.5 Hz, Ar), 128.6 (d, J CP = 7.4 Hz, Ar), 128.6 (s, Ar), 128.5 (s, Ar), 128.5 (s, Ar), 128.4 (s, Ar), 128.2 (d, J CP = 6.0 Hz, Ar), 128.0 (s, Ar), 127.8 (d, J CP = 6.7 Hz, Ar), 41.1 (t, J CP = 14.9 Hz, CH), 32.5 (dd, J CP = 21.1, J CP = 15.5 Hz, CH 2 ). 31 P NMR (162 MHz, CDCl 3 ): δ 3.2 (d, J PP = 17.0 Hz, PCH), -21.6 (d, J PP = 16.8 Hz, PCH 2 ). Anal. Calcd for C 32 H 27 ClP 2 : C, 75.52; H, 5.35. Found: C, 75.44; H, 5.34. (1-(4-bromophenyl)ethane-1,2-diyl)bis(diphenylphosphine oxide). [7] 1 H NMR (400 MHz, CDCl 3 ): δ 8.00 8.05 (m, 2 H, Ar), 7.29 7.58 (m, 13 H, Ar), 6.90 7.25 (m, 9 H, Ar), 4.21 4.82 (m, 1 H, CH), 3.04 3.13 (m, 1 H, CH 2 ), 2.75 2.85 (m, 1 H, CH 2 ). 13 C NMR (101 MHz, CDCl 3 ): δ 134.3 (s, Ar), 133.2 (d, J CP = 5.9 Hz, Ar), 132.2 (d, J CP = 2.5 Hz, Ar), 131.8 (d, J CP = 2.0 Hz, Ar), 131.7 (d, J CP = 5.7 Hz, Ar), 131.5 (d, J CP = 2.6 Hz, Ar), 131.4 (d, J CP = 8.5 Hz, Ar), 131.0 (s, Ar), 130.9 (d, J CP = 1.5 Hz, Ar), 130.8 (s, Ar), 130.7 (d, J CP = 2.0 Hz, Ar), 130.6 (s, Ar), 130.2 (d, J CP = 9.3 Hz, Ar), 130.1 (s, Ar), 129.1 (d, J CP = 11.4 Hz, Ar), 128.7 (d, J CP = 11.6 Hz, Ar), 128.2 (s, Ar), 128.1 (s, Ar), 127.9 (s, Ar), 121.2 (d, J CP = 3.0 Hz, Ar), 38.8 (d, J CP = 65.7 Hz, CH), 30.2 (d, J CP = 69.0 Hz, CH 2 ). 31 P NMR (162 MHz, CDCl 3 ): δ 34.3 (d, J PP = 46.6 Hz, PCH), 29.3 (d, J PP = 46.5 Hz, PCH 2 ). (1-(2-methoxyphenyl)ethane-1,2-diyl)bis(diphenylphosphine oxide). 1 H NMR (400 MHz, CDCl 3 ): δ 8.03 8.07 (m, 2 H, Ar), 7.29 7.59 (m, 13 H, Ar), 7.06 7.23 (m, 6 H, Ar), 6.86 (t, J = 7.7 Hz, 1 H, Ar), 6.70 (t, J = 7.4 Hz, 1 H, Ar), 6.13 (d, J = 8.2 Hz, 1 H, Ar), 4.96 (br, 1 H, CH), 3.29 (s, 3 H, OCH 3 ), 2.81 3.10 (m, 2 H, CH 2 ). 13 C NMR (101 MHz, CDCl 3 ): δ 156.0 (d, J CP = 4.8 Hz, Ar), 134.2 (s, Ar), 133.2 (s, Ar), 132.2 (s, Ar), 131.8 (d, J CP = 2.0 Hz, Ar), 131.6 (s, Ar), 131.5 (s, Ar), 131.2 (s, Ar), 130.8 (s, Ar), 130.8 (s, Ar), 130.7 (s, Ar), 130.6 (s, Ar), 130.3 (d, J CP = 9.3 Hz, Ar), 129.6 (s, Ar), 128.8 (d, J CP = 11.2 Hz, Ar), 128.4 (d, J CP = 11.6 Hz, Ar), 128.0 (s, Ar), 127.4 (d, J CP = 12.0 Hz, Ar), 127.2 (d, J CP = 11.9 Hz, Ar), 123.0 (d, J CP = 5.4 Hz, Ar), 120.1 (d, J CP = 2.2 Hz, Ar), 109.3 (s, Ar), 54.4 (s, OCH 3 ), 29.9 (d, J CP = 69.6 Hz, CH), 28.8 (d, J CP = 69.9 Hz, CH 2 ). 31 P NMR (162 MHz, CDCl 3 ): δ 35.8 (d, J PP = 47.6 Hz, PCH), 30.0 (d, J PP = 47.6 Hz, PCH 2 ). HRMS (ESI): [M+H] + calcd. for C 33 H 31 O 3 P 2 : 537.1748; Found: 537.1748. S11

(1-(pyridin-2-yl)ethane-1,2-diyl)bis(diphenylphosphine oxide). [8] 1 H NMR (400 MHz, CDCl 3 ): δ 8.21 (d, J = 3.7 Hz, 1 H, Ar), 7.97 (t, J = 8.0 Hz, 2 H, Ar), 7.31 7.64 (m, 14 H, Ar), 7.11 7.21 (m, 5 H, Ar), 6.77 6.85 (m, 2 H, Ar), 4.47 4.56 (m, 1 H, CH), 3.63 (t, J = 14.4 Hz, 1 H, CH 2 ), 2.80 2.90 (m, 1 H, CH 2 ). 13 C NMR (101 MHz, CDCl 3 ): δ 154.2 (d, J CP = 5.5 Hz, Ar), 148.8 (s, Ar), 135.3 (s, Ar), 133.7 (s, Ar), 132.8 (s, Ar), 132.1 (s, Ar), 132.0 (s, Ar), 131.6 (s, Ar), 131.4 (d, J CP = 8.6 Hz, Ar), 131.3 (s, Ar), 131.1 (s, Ar), 131.0 (s, Ar), 130.9 (s, Ar), 130.7 (d, J CP = 9.8 Hz, Ar), 130.6 (s), 130.3 (d, J CP = 9.3 Hz, Ar), 130.1 (s, Ar), 128.8 (d, J CP = 11.5 Hz, Ar), 128.5 (d, J CP = 11.7 Hz, Ar), 127.9 (s, Ar), 127.8 (s, Ar), 127.7 (s, Ar), 124.9 (d, J CP = 4.0 Hz, Ar), 121.5 (s, Ar), 41.8 (d, J CP = 62.7 Hz, CH), 28.2 (d, J CP = 69.0 Hz, CH 2 ). 31 P NMR (162 MHz, CDCl 3 ): δ 34.4 (d, J PP = 46.0 Hz, PCH), 30.1 (d, J PP = 46.0 Hz, PCH 2 ). (1-(thiophen-2-yl)ethane-1,2-diyl)bis(diphenylphosphine oxide). 1 H NMR (400 MHz, CDCl 3 ): δ 8.01 8.05 (m, 2 H, Ar), 7.16 7.57 (m, 18 H, Ar), 6.80 (d, J = 4.8 Hz, 1 H, Ar), 6.69 (s, 1 H, Ar), 6.75 (t, J = 4.0 Hz, 1 H, Ar), 4.63 4.71 (m, 1 H, CH), 2.77 3.14 (m, 2 H, CH 2 ). 13 C NMR (101 MHz, CDCl 3 ): δ 135.8 (d, J CP = 6.9 Hz, Ar), 134.4 (s, Ar), 133.4 (s, Ar), 132.2 (d, J CP = 2.6 Hz, Ar), 131.9 (s, Ar), 131.7 (d, J CP = 2.7 Hz, Ar), 131.6 (d, J CP = 8.6 Hz, Ar), 131.5 (s, Ar), 131.0 (d, J CP = 2.8 Hz, Ar), 130.9 (s, Ar), 130.8 (s, Ar), 130.8 (s, Ar), 130.7 (s, Ar), 130.6 (s, Ar), 130.2 (d, J CP = 9.4 Hz, Ar), 129.8 (s, Ar), 129.1 (d, J CP = 11.4 Hz, Ar), 128.6 (d, J CP = 11.7 Hz, Ar), 128.4 (d, J CP = 6.9 Hz, Ar), 128.0 (d, J CP = 8.5 Hz, Ar), 127.9 (d, J CP = 8.6 Hz, Ar), 126.2 (d, J CP = 2.5 Hz, Ar), 125.4 (d, J CP = 2.8 Hz, Ar), 34.8 (dd, J CP = 67.9, J CP = 4.0 Hz, CH), 31.3 (d, J CP = 69.1 Hz, CH 2 ). 31 P NMR (162 MHz, CDCl 3 ): δ 34.3 (d, J PP = 44.4 Hz), 29.9 (d, J PP = 44.4 Hz). HRMS (ESI): [M+H] + calcd. for C 30 H 27 O 2 P 2 S: 513.1207; Found: 513.1204. Hexane-1,2-diylbis(diphenylphosphine oxide). 1 H NMR (400 MHz, CDCl 3 ) δ 7.72 7.81 (m, 6 H, Ar), 7.37 7.52 (m, 14 H, Ar), 3.01 (br, 1 H, PCH), 2.52 2.70 (m, 2 H, PCH 2 ), 1.68 1.77 (m, 1 H, n Bu), 1.22 1.51 (m, 2 H, n Bu), 0.75 0.94 (m, 3 H, n Bu), 0.52 (t, J = 7.2 Hz, 3 H, n Bu). 13 C NMR (101 MHz, CDCl 3 ): δ 133.7 (d, J CP = 9.3 Hz, Ar), 132.7 (d, J CP = 10.9 Hz, Ar), 132.7 (d, J CP = 14.8 Hz, Ar), 131.8 (d, J CP = 2.5 Hz, Ar), 131.6 (d, J CP = 2.4 Hz, Ar), 131.4 (d, J CP = 14.7 Hz, Ar), 131.0 (d, J CP = 8.4 Hz, Ar), 130.9 (d, J CP = 8.9 Hz, Ar), 130.7 (d, J CP = 9.4 Hz, Ar), 130.5 (d, J CP = 9.3 Hz, Ar), 128.8 (d, J CP = 11.2 Hz, Ar), 128.6 (d, J CP = 3.3 Hz, Ar), 128.5 (s, Ar), 128.5 (s, Ar), 128.4 (s, Ar), 31.2 (dd, J CP = 69.3, J CP = 3.7 Hz, PCH), 29.0 (d, J CP = 4.3 Hz, CH 2 CH 2 CH 2 CH 3 ), 27.9 (s, CH 2 CH 2 CH 2 CH 3 ), 27.3 (d, J CP = S12

69.0 Hz, PCH 2 ), 22.5 (s, CH 2 CH 2 CH 2 CH 3 ), 13.4 (s, CH 2 CH 2 CH 2 CH 3 ). 31 P NMR (162 MHz, CDCl 3 ): δ 37.1 (d, J PP = 47.6 Hz, PCH), 30.1 (d, J PP = 47.7 Hz, PCH 2 ). HRMS (ESI): [M+H] + calcd. for C 30 H 33 O 2 P 2 : 487.1956; Found: 487.1955. 2,3-bis(diphenylphosphanyl)-N,N-dimethylpropan-1-amine. [9] 1 H NMR (400 MHz, CDCl 3 ): δ 7.40 7.44 (m, 2 H, Ar), 7.29 7.39 (m, 10 H, Ar), 7.20 7.26 (m, 8 H, Ar), 2.40 2.57 (m, 2 H, CH 2 NMe 2 ), 2.24 2.32 (m, 2 H, CH 2 PPh 2 ), 2.11 (s, 6 H, NMe 2 ), 2.00 2.08 (m, 1 H, CHPPh 2 ). 13 C NMR (101 MHz, CDCl 3 ): δ 139.3 (d, J CP = 7.1 Hz, Ar), 139.1 (d, J CP = 8.3 Hz, Ar), 136.6 (d, J CP = 16.1 Hz, Ar), 135.9 (d, J CP = 16.8 Hz, Ar), 134.0 (d, J CP = 19.2 Hz, Ar), 133.6 (s, Ar), 133.2 (d, J CP = 18.3 Hz, Ar), 132.5 (d, J CP = 18.1 Hz, Ar), 128.7 (d, J CP = 3.8 Hz, Ar), 128.3 (s, Ar), 128.2 (d, J CP = 1.6 Hz, Ar), 128.2 (s, Ar), 128.17 (s, Ar), 128.1 (d, J CP = 2.0 Hz, Ar), 61.1 (dd, J CP = 13.0, J CP = 7.7 Hz), 45.8 (s), 31.6 (dd, J CP = 15.8, J CP = 10.8 Hz), 29.3 (dd, J CP = 16.1, J CP = 8.3 Hz). 31 P NMR (162 MHz, CDCl 3 ): δ -4.0 (d, J PP = 31.6 Hz, PCH), -19.7 (d, J PP = 31.5 Hz, PCH 2 ). Figure S8. 1 H NMR spectrum of complex 1 in C 6 D 6. S13

Figure S9. 13 C NMR spectrum of complex 1 in C 6 D 6. Figure S10. 31 P NMR spectrum of complex 1 in C 6 D 6. S14

Figure S11. 1 H NMR spectrum of complex 2 in C 6 D 6. Figure S12. 13 C NMR spectrum of complex 2 in C 6 D 6. S15

Figure S13. 31 P NMR spectrum of complex 2 in C 6 D 6. Figure S14. 1 H NMR spectrum of complex 4 in C 6 D 6. S16

Figure S15. 13 C NMR spectrum of complex 4 in C 6 D 6. Figure S16. 1 H NMR spectrum of (1-(p-tolyl)ethane-1,2-diyl)bis(diphenylphosphine) in CDCl 3. S17

Figure S17. 13 C NMR spectrum of (1-(p-tolyl)ethane-1,2-diyl)bis(diphenylphosphine) in CDCl 3. Figure S18. 31 P NMR spectrum of (1-(p-tolyl)ethane-1,2-diyl)bis(diphenylphosphine) in CDCl 3. S18

Figure S19. 1 H NMR spectrum of (1-(4-methoxyphenyl)ethane-1,2-diyl)bis(diphenylphosphine) in CDCl 3. Figure S20. 13 C NMR spectrum of (1-(4-methoxyphenyl)ethane-1,2-diyl)bis(diphenylphosphine) in CDCl 3. S19

Figure S21. 31 P NMR spectrum of (1-(4-methoxyphenyl)ethane-1,2-diyl)bis(diphenylphosphine) in CDCl 3. Figure S22. 1 H NMR spectrum of 4-(1,2-bis(diphenylphosphino)ethyl)-N,N-dimethylaniline in CDCl 3. S20

Figure S23. 13 C NMR spectrum of 4-(1,2-bis(diphenylphosphino)ethyl)-N,N-dimethylaniline in CDCl 3. Figure S24. 31 P NMR spectrum of 4-(1,2-bis(diphenylphosphino)ethyl)-N,N-dimethylaniline in CDCl 3. S21

Figure S25. 1 H NMR spectrum of (1-(4-(tert-butyl)phenyl)ethane-1,2-diyl)bis(diphenylphosphine) in CDCl 3. Figure S26. 13 C NMR spectrum of (1-(4-(tert-butyl)phenyl)ethane-1,2-diyl)bis(diphenylphosphine) in CDCl 3. S22

Figure S27. 31 P NMR spectrum of (1-(4-(tert-butyl)phenyl)ethane-1,2-diyl)bis(diphenylphosphine) in CDCl 3. Figure S28. 1 H NMR spectrum of (1-(4-fluorophenyl)ethane-1,2-diyl)bis(diphenylphosphine) in CDCl 3. S23

Figure S29. 13 C NMR spectrum of (1-(4-fluorophenyl)ethane-1,2-diyl)bis(diphenylphosphine) in CDCl 3. Figure S30. 31 P NMR spectrum of (1-(4-fluorophenyl)ethane-1,2-diyl)bis(diphenylphosphine) in CDCl 3. S24

Figure S31. 1 H NMR spectrum of (1-(4-chlorophenyl)ethane-1,2-diyl)bis(diphenylphosphine) in CDCl 3. Figure S32. 13 C NMR spectrum of (1-(4-chlorophenyl)ethane-1,2-diyl)bis(diphenylphosphine) in CDCl 3. S25

Figure S33. 31 P NMR spectrum of (1-(4-chlorophenyl)ethane-1,2-diyl)bis(diphenylphosphine) in CDCl 3. Figure S34. 1 H NMR spectrum of (1-(4-bromophenyl)ethane-1,2-diyl)bis(diphenylphosphine oxide) in CDCl 3. S26

Figure S35. 13 C NMR spectrum of (1-(4-bromophenyl)ethane-1,2-diyl)bis(diphenylphosphine oxide) in CDCl 3. Figure S36. 31 P NMR spectrum of (1-(4-bromophenyl)ethane-1,2-diyl)bis(diphenylphosphine oxide) in CDCl 3. S27

Figure S37. 1 H NMR spectrum of (1-(2-methoxyphenyl)ethane-1,2-diyl)bis(diphenylphosphine oxide) in CDCl 3. Figure S38. 13 C NMR spectrum of (1-(2-methoxyphenyl)ethane-1,2-diyl)bis(diphenylphosphine oxide) in CDCl 3. S28

Figure S39. 31 P NMR spectrum of (1-(2-methoxyphenyl)ethane-1,2-diyl)bis(diphenylphosphine oxide) in CDCl 3. Figure S40. 1 H NMR spectrum of (1-(pyridin-2-yl)ethane-1,2-diyl)bis(diphenylphosphine oxide) in CDCl 3. S29

Figure S41. 13 C NMR spectrum of (1-(pyridin-2-yl)ethane-1,2-diyl)bis(diphenylphosphine oxide) in CDCl 3. Figure S42. 31 P NMR spectrum of (1-(pyridin-2-yl)ethane-1,2-diyl)bis(diphenylphosphine oxide) in CDCl 3. S30

Figure S43. 1 H NMR spectrum of (1-(thiophen-2-yl)ethane-1,2-diyl)bis(diphenylphosphine oxide) in CDCl 3. Figure S44. 13 C NMR spectrum of (1-(thiophen-2-yl)ethane-1,2-diyl)bis(diphenylphosphine oxide) in CDCl 3. S31

Figure S45. 31 P NMR spectrum of (1-(thiophen-2-yl)ethane-1,2-diyl)bis(diphenylphosphine oxide) in CDCl 3. Figure S46. 1 H NMR spectrum of 2,3-bis(diphenylphosphanyl)-N,N-dimethylpropan-1-amine in CDCl 3. S32

Figure S47. 13 C NMR spectrum of 2,3-bis(diphenylphosphanyl)-N,N-dimethylpropan-1-amine in CDCl 3. Figure S48. 31 P NMR spectrum of 2,3-bis(diphenylphosphanyl)-N,N-dimethylpropan-1-amine in CDCl 3. S33

Figure S49. 1 H NMR spectrum of hexane-1,2-diylbis(diphenylphosphine oxide) in CDCl 3. Figure S50. 13 C NMR spectrum of hexane-1,2-diylbis(diphenylphosphine oxide) in CDCl 3. S34

Figure S51. 31 P NMR spectrum of hexane-1,2-diylbis(diphenylphosphine oxide) in CDCl 3. References: (S1) (a) Kuhn, N.; Kratz, T. Synthesis 1993, 6, 561-562. (b) Rensburg, H.; Tooze, R. P.; Foster, D. F.; Otto, S. Inorg. Chem. 2007, 46, 1963-1965. ( c) Scott, N. M.; Dorta, R.; Stevens, E. D.; Correa, A.; Cavallo, L.; Nolan, S. P. J. Am. Chem. Soc. 2005, 127, 3516-3526. (d) Arduengo, A. J.; Krafczyk, III, R.; Schmutzler, R. Tetrahedron, 1999, 55, 14523-l4534. (e) Fortman, G. C. ; Slawin, A. M. Z.; Nolan, S. P. Organometallics 2010, 29, 3966-3972. (S2) Sheldrick, G. M. SHELXS-90/96, Program for Structure Solution, Acta Crystallogr. Sect A 1990, 46, 467. (S3) Sheldrick, G. M. SHELXL 97, Program for Crystal structure Refinement, University of Goettingen:Geottingen, Germany, 1997. (S4) Frisch, M. J.; Trucks, G. W.; Schlegel, H. B.; Scuseria, G. E.; Robb, M. A.; Cheeseman, J. R.; Montgomery, J. A.; Vreven, T.; Kudin, Jr., K. N.; Burant, J. C.; Millam, J. M.; Iyengar, S. S.; Tomasi, J.; Barone, V.; Mennucci, B.; Cossi, M.; Scalmani, G.; Rega, N.; Petersson, G. A.; Nakatsuji, H.; Hada, M.; Ehara, M.; Toyota, K.; Fukuda, R.; Hasegawa, J.; Ishida, M.; Nakajima, T.; Honda, Y.; Kitao, O.; Nakai, H.; Klene, M.; Li, X.; Knox, J. E.; Hratchian, H. P.; Cross, J. B.; Adamo, C.; Jaramillo, J.; Gomperts, R.; Stratmann, R. E.; Yazyev, O.; Austin, A. J.; Cammi, R.; Pomelli, C.; Ochterski, J. W.; Ayala, P. Y.; Morokuma, K.; Voth, G. A.; Salvador, P.; Dannenberg, J. J.; Zakrzewski, V. G.; Dapprich, S.; Daniels, A. D.; Strain, M. C.; Farkas, O.; Malick, D. K.; Rabuck, A. D.; Raghavachari, K.; Foresman, J. B.; Ortiz, J. V.; Cui, Q.; Baboul, A. G.; Clifford, S.; Cioslowski, J.; Stefanov, B. B.; Liu, G.; Liashenko, A.; Piskorz, P.; Komaromi, I.; Martin, R. L.; Fox, D. J.; Keith, T.; Al-Laham, M. A.; Peng, C. Y.; S35

Nanayakkara, A.; Challacombe, M.; Gill, P. M. W.; Johnson, B.; Chen, W.; Wong, M. W.; Gonzalez, C.; Pople, J. A. Gaussian 03, Revision C.02, Gaussian, Inc., Wallingford CT, 2004 (S5) King, R. B.; Bakos, J.; Hoff, C. D.; Markó, L. J. Org. Chem., 1979, 44, 1729-1731. (S6) Kamitani, M.; Itazaki, M.; Tamiya, C.; Nakazawa, H. J. Am. Chem. Soc. 2012, 134, 11932-11935. (S7) Stone, J. J.; Stockland Jr., R. A.; Reyes Jr., J. M.; Kovach, J.; Goodman, C. C.; Tillman, T. S. J. Mol. Catal. A-Chem., 2005, 226, 11-21. (S8) Allen, Jr., A.; Ma, L.; Lin, W. Tetrahedron Lett., 2002, 43, 3707 3710. (S9) Giuseppe, A. D. Luca, R. D.; Castarlenas, R.; Pérez-Torrente, J. J.; Crucianelli, M.; Oro, L. A. Chem. Commun. 2016, 52, 5554-5557. S36