Chloro(1,5-cyclooctadiene)rhodium(I) Dimer

Typical Procedure:
In a nitrogen-filled dry box, the appropriate o-allylbenzaldehyde (0.20 mmol, 1.0 eq.), [Rh(COD)Cl]₂ (2.5 mg, 0.0050 mmol, 0.025 eq.), (R)-DTBM-SEGPHOS^® (11.8 mg, 0.010 mmol, 0.050 eq.), NaBARF (8.9 mg, 0.010 mmol, 0.050 eq.), and anhydrous 1,4-dioxane (1 mL) are added to a 1-dram vial. The vial is sealed with a PFTE/silicone-lined septum cap and removed from the dry box. The reaction mixture is heated to 100 °C and allowed to stir at this temperature until the reaction is judged to be complete by TLC analysis. The mixture is cooled to room temperature, filtered through a pad of silica gel (eluting with EtOAc), and concentrated under reduced pressure. The crude reaction mixture is purified by flash column silica gel chromatography (hexane/EtOAc or hexane/Et₂O) to yield the corresponding products.

Typical procedure: Under nitrogen atmosphere, a mixture of an arylboron compounds (0.50 mmol), [RhCl(cod)]2 (6.2 mg, 13 µmol), DPPB (11.7 mg, 28 µmol), and K3PO4 (320 mg, 1.5 mmol) is diluted with toluene (2.0 mL). Alkenyl acetate (1.1 or 2.5 mmol) and tert-amyl alcohol (0.55-1.5 mmol) are added into the resulting suspension at room temperature. The mixture is stirred at 100℃ for 24 h and then diluted with hexane (2.0 mL) or EtOAc (2.0 mL). After the filtration through a Celite pad, solvent is removed from the filtrate under reduced pressure. The residue is purified with a flash column chromatography (EtOAc-hexane) to give the desired product.

Typical procedure: A dry Schlenk tube flask is charged with the potassium trifluoroborate salt (0.45 mmol), [RhCl(cod)]2 (2.5 mol%, 3.6 mg) and the aldehyde (0.3 mmol). After cycles of vacuum and nitrogen (3 cycles), deoxygenated 1,4-dioxane (1.4 mL) and deoxygenated H2O (240 µL) are added. The reaction mixture is stirred at 60-100°C and the progress of the reaction is checked by TLC. The mixture is cooled to room temperature, saturated NH4Cl solution is added, and then the mixture is extracted with EtOAc. The combined organic layers are dried over MgSO4. Concentration and purification through silica gel column chromatography gives the products.