85% |
With copper(l) chloride; In dichloromethane; for 1.16667h;Inert atmosphere; Reflux; |
To a dry 100 mL round-bottom flask containing a magnetic stirbar, under argon, was added 1.79 g (2.1 mmol, 1.0 equiv) [5], CuCl (521 mg, 5.28 mmol, 2.51 equiv), and 25 mL of anhydrous CH2Cl2. Ligand precursor [2] (403 mg, 2.1 mmol, 1.0 equiv) was added to the reddish solution in 20 mL of CH2Cl2 at room temperature. A reflux condenser was added and the mixture was heated for 70 minutes, under argon. The crude product was concentrated and loaded onto silica gel and eluted with 2:1 pentane:CH2Cl2 then 1:1 pentane:CH2Cl2 to remove a dark green band. The column was washed with CH2Cl2, then Et2O. The green and yellow bands were combined and concentrated under reduced pressure to yield a dark green solid. The solvents are removed under reduced pressure and the solid was crystallized from hexane to yield 1.07 g (1.70 mmol, 85%) of [6]. 1H NMR (300 MHz, CDCl3) delta: 16.56 (s, 1H, Ru=CHAr), 7.48 (m, 1H, aromatic CH), 7.07 (s, 4H, mesityl aromatic CH), 6.93 (dd, J=7.4 Hz, 1.6 Hz, 1H, aromatic CH), 6.85 (dd, J=7.4 Hz, 1H, aromatic CH), 6.79 (d, J=8.6 Hz, 1H, aromatic CH) 4.90 (septet, J=6.3 Hz, 1H, (CH3)2CHOAr), 4.18 (s, 4H, N(CH2)2N), 2.48 (s, 12H, mesityl o-CH3), 2.40 (s, 6H, mesityl p-CH3), 1.27 (d, J=5.9 Hz, 6H, (CH3)2CHOAr. 13C NMR (75 MHz, CDCl3) delta: 296.8 (q, J=61.5 Hz), 211.1, 152.0, 145.1, 145.09, 138.61, 129.4 (d, JNC 3.9 Hz), 129.3, 129.2, 122.6, 122.1, 122.8, 74.9 (d, JOC 10.7 Hz), 51.4, 30.9, 25.9, 21.01. |