Principales cambios de Symfony 1.2

(65) Yeung, C. M.; Klein, L. L. Tetrahedron Lett. 1990, 31, 2121–2124.

Zinc 3,6-dichlorobenzene-1,2-dithiolate (1.48): Prepared through synthesis route 2 starting from 1,2-dithiol 1.47. A mixture of 3,6-dichlorobenzene-1,2-dithiol (211 mg, 1.00 mmol, 1.00 equiv), Zn(OAc)2•2H2O (878 mg, 4.00 mmol, 4.00 equiv) and ethylenediamine (0.40 mL, 6.00 mmol, 6.00 equiv) in i-PrOH (8 mL) was allowed to stir for 1 hour at 22 °C. The precipitated solid was filtered, washed with methanol (5.0 mL) and hot chloroform (5.0 mL), and dried in a vacuum dessicator overnight to afford 1.48 (261 mg, 0.95 mmol, 95% yield) as white solid.

Zinc 3,6-dimethylbenzene-1,2-dithiolate (1.81): Prepared through route 1 starting from 2,5-dimethylbenzenethiol and isolated as white solid in 21% overall yield.

Zinc 3-bromo-6-chlorobenzene-1,2-dithiolate (1.82): Prepared through route 1 starting from 2-bromo-5-chlorobenzenethiol and isolated as white solid in 28% overall yield.

2,5-Dibromobenzenethiol (1.83): Prepared in analogy to a previously reported procedure.⁶⁶ To a suspension of 2,5-dibromoaniline (1.25 g, 5.00 mmol, 1.00 equiv) in 6M HCl (9.1 mL) at –5 °C was added dropwise a solution of NaNO2 (0.380 g, 5.50 mmol, 1.10 equiv) in water (2.5 mL), and the mixture was allowed to stir for 1 hour at –5

°C. To the mixture was added a solution of EtOCS2K (1.36 g, 8.50 mmol, 1.70 equiv) in water (2.5 mL), and the mixture was allowed to stir for 4 hours at 80 °C. The aqueous layer was washed with Et₂O (3 x 20.0 mL) and the combined organic layers were dried

(66) Agou, T.; Kobayashi, J.; Kawashima, T. J. Chem. Eur. J. 2007, 13, 8051–8060.

over anhydrous MgSO4, filtered and concentrated in vacuo to afford a solid. A solution of the unpurified product in tetrahydrofuran (2.5 mL) was slowly added to a suspension of LiAlH4 (0.455 g, 12.0 mmol, 2.40 equiv) in tetrahydrofuran (5 mL) at 0 °C. The mixture was allowed to stir for 12 hours at 22 °C. The reaction was quenched by pouring into a mixture of conc. HCl (2.5 mL) and crushed ice and washing with Et2O (3 x 20.0 mL).

The combined organic layers were dried over anhydrous MgSO4, filtered and concentrated in vacuo to afford 1.83 (0.805 g, 3.00 mmol, 60% yield) as yellow oil, which was used in the next step without purification.

Zinc 3,6-dibromobenzene-1,2-dithiolate (1.84): Prepared through route 1 starting from 1.83 and isolated as white solid in 15% overall yield.

2,3,4,5-Tetrafluorobenzenethiol (1.85): To a stirred solution of n-BuLi (0.69 mL, 1.10 mmol, 1.10 equiv) in tetrahydrofuran (2 mL) at –78 °C was added 1,2,3,4-tetrafluorobenzene (150 mg, 1.00 mmol, 1.00 equiv) over 30 minutes. The solution was allowed to stir for a further 45 minutes at the same temperature, after which dry, powdered sulfur (35.3 mg, 1.10 mmol, 1.10 equiv) was added in portions over 30 minutes. The solution was allowed to stir for a further 30 minutes at –78 °C. The reaction was quenched with 6M HCl (1.5 mL) and washed with Et₂O (3 x 5.0 mL). The combined organic layers were washed with water (10 mL), dried over anhydrous MgSO4, filtered and concentrated in vacuo to afford 1.85 (75.0 mg, 0.41 mmol, 41% yield) as yellow oil, which was used in the next step without purification.

3,4,5,6-Tetrafluorobenzene-1,2-dithiol (1.86): To a stirred solution of n-BuLi (0.28 mL, 0.45 mmol, 1.10 equiv) in tetrahydrofuran (1 mL) at –78 °C was added 1.85 (75.0 mg, 0.41 mmol, 1.00 equiv) in tetrahydrofuran (1 mL) over 30 minutes. The solution was

allowed to stir for a further 45 minutes at –78 °C, after which dry, powdered sulfur (14.4 mg, 0.45 mmol, 1.10 equiv) was added in portions over 30 minutes. The solution was allowed to stir for a further 30 minutes at –78 °C. The reaction was quenched with 6M HCl (0.6 mL) and washed with Et2O (3 x 3.0 mL). The combined organic layers were washed with water (5.0 mL), dried over anhydrous MgSO4, filtered and concentrated in vacuo to afford 1.86 (39.5 mg, 0.18 mmol, 45% yield) as brown oil, which was used in

the next step without purification.

Zinc 3,4,5,6-tetrafluorobenzene-1,2-dithiolate (1.87): Prepared through route 2 starting from 1.86. A mixture of 1.86 (214 mg, 1.00 mmol, 1.00 equiv), Zn(OAc)2•2H2O (878 mg, 4.00 mmol, 4.00 equiv) and ethylenediamine (0.40 mL, 6.00 mmol, 6.00 equiv) in i-PrOH (8 mL) was allowed to stir for 1 hour at 22 °C. The precipitated solid was filtered, washed with methanol (5.0 mL) and hot chloroform (5.0 mL), and dried in a vacuum dessicator overnight to afford 1.87 (155 mg, 0.56 mmol, 56% yield) as white solid.

b. Preparation of Ru-based dithiolate complexes

Complex Ru-9: To a 2-dram vial charged with a stir bar and zinc dithiolate 1.48 (26.9 mg, 0.098 mmol, 2.00 equiv) under N2 atmosphere, a solution of second-generation complex Ru-5 (30.7 mg, 0.049 mmol, 1.00 equiv) in tetrahydrofuran (610 µL) is added.

The resulting mixture is allowed to stir for 5 hours at 22 °C, at which time the solvent is evaporated under vacuum. Residual tetrahydrofuran is removed through co-evaporation with pentane (2 x 2 mL). The obtained solid is dissolved in dichloromethane and passed through a short column of Celite (4 cm in height) in a pipette (~0.5 cm diameter) with dichloromethane (10 mL). After removal of dichloromethane from the filtrate and co-evaporation with pentane, Ru-9 is isolated as brown solid (31.9 mg, 0.042 mmol, 85%

yield); ¹H NMR (400 MHz, CD2Cl2): δ 14.30 (1H, s), 7.32–7.26 (1H, m), 7.10 (1H, d, J

= 8.1 Hz), 6.96 (2H, s), 6.87 (1H, dd, J = 8.1, 0.6 Hz), 6.82–6.76 (2H, m), 6.61 (1H, dd, J

= 7.5, 1.6 Hz), 6.45–6.00 (2H, br s), 5.29–5.25 (1H, m), 3.92 (4H, br s), 2.52 (6H, br s), 2.30–2.10 (3H, br s), 2.20 (6H, s), 1.75–1.55 (3H, br s), 1.68 (3H, d, J = 6.6 Hz), 1.50 (3H, d, J = 6.6 Hz); ¹³C NMR (100 MHz, CD2Cl2): δ 253.9 (d, J = 13.6 Hz), 218.0, 154.9, 154.2, 142.4, 141.9, 138.8 (br), 136.6 (br), 136.3 (br), 131.6, 130.0, 130.0, 129.7, 128.0, 124.7, 123.4, 122.6, 121.9, 115.9, 82.2, 52.0, 24.5, 21.6, 21.3, 19.4 (br), 18.0 (br).

Complex Ru-10: To a 2-dram vial charged with a stir bar and zinc dithiolate 1.84 (35.6 mg, 0.098 mmol, 2.00 equiv) under N2 atmosphere, a solution of second-generation complex Ru-5 (30.7 mg, 0.049 mmol, 1.00 equiv) in tetrahydrofuran (610 µL) is added.

The resulting mixture is allowed to stir for 5 hours at 22 °C, at which time the solvent is evaporated under vacuum. Residual tetrahydrofuran is removed through co-evaporation with pentane (2 x 2 mL). The obtained solid is dissolved in dichloromethane and passed through a short column of Celite (4 cm in height) in a pipette (~0.5 cm diameter) with dichloromethane (10 mL). After removal of dichloromethane from the filtrate and co-evaporation with pentane, Ru-10 is isolated as brown solid (33.5 mg, 0.039 mmol, 80%

yield); ¹H NMR (400 MHz, CD2Cl2): δ 14.29 (1H, s), 7.35–7.27 (1H, m), 7.11 (1H, d, J

128.0, 126.9, 125.5, 124.7, 123.2, 122.6, 121.2, 115.8, 82.0, 52.0, 24.5, 21.7, 21.3, 19.4 (br), 18.6.

Complex Ru-11: To a 2-dram vial charged with a stir bar and zinc dithiolate 1.82 (31.3 mg, 0.098 mmol, 2.00 equiv) under N2 atmosphere, a solution of second-generation Hoveyda-Grubbs catalyst (30.7 mg, 0.049 mmol, 1.00 equiv) in tetrahydrofuran (610 µL) is added. The resulting mixture is allowed to stir for 5 hours at 22 °C, at which time the solvent is evaporated under vacuum. Residual tetrahydrofuran is removed through co-evaporation with pentane (2 x 2 mL). The obtained solid is dissolved in dichloromethane and passed through a short column of Celite (4 cm in height) in a pipette (~0.5 cm diameter) with dichloromethane (10 mL). After removal of dichloromethane from the filtrate and co-evaporation with pentane, Ru-11 is isolated as brown solid (33.3 mg, 122.3, 122.3, 120.3, 115.9, 82.2, 82.1, 52.0, 26.2, 24.5, 24.5, 21.7, 21.6, 21.3, 19.6 (br), 19.4 (br).

Complex Ru-12: To a 2-dram vial charged with a stir bar and zinc dithiolate 1.87 (27.2 mg, 0.098 mmol, 2.00 equiv) under N2 atmosphere, a solution of Ru-5 (30.7 mg, 0.049

mmol, 1.00 equiv) in tetrahydrofuran (610 µL) is added. The resulting mixture is allowed to stir for 5 hours at 22 °C, at which time the solvent is evaporated under vacuum.

Residual tetrahydrofuran is removed through co-evaporation with pentane (2 x 2 mL).

The obtained solid is dissolved in dichloromethane and passed through a short column of Celite (4 cm in height) in a pipette (~0.5 cm diameter) with dichloromethane (10 mL).

After removal of dichloromethane from the filtrate and co-evaporation with pentane, Ru-12 is isolated as brown solid (30.7 mg, 0.040 mmol, 82% yield); ¹H NMR (400 MHz,

In an N2-filled glove box, an oven-dried 4 mL vial equipped with a magnetic stir bar is charged with strained alkene substrate (1.0 equiv) and terminal olefin cross partner (10 equiv). To this vial, a solution of Ru complex Ru-7 (2.0−5.0 mol %) in dichloromethane is added. The resulting solution is allowed to stir for 2−12 hours at 22−40 °C, after which the reaction is quenched by addition of wet diethyl ether and concentrated in vacuo