Toepassing
Iridium / Axially Chiral Phosphoramidite Complex Catalyzed Allylic Substitution of Allyl Carbonate Derivatives

In a nitrogen-filled atmosphere, [Ir(cod)Cl]2 (2.7 mg, 0.0040 mmol), the ligand (4.3 mg, 0.0080 mmol), KF (12 mg, 0.20 mmol), 18-crown-6 (53 mg, 0.20 mmol) and a Teflon-coated magnetic stirring bar are added to a 1-dram vial. Then, anhydrous THF (0.40 mL) is added. The mixture is stirred for 5 min. at ambient temperature before allyl carbonate derivative (0.20 mmol) and the silyl enolate derivative (0.40 mmol, 2.0 equiv) are added. The vial is sealed with a cap and stirred at 50 °C for 12 h. Then, water (1 mL) is added to the reaction mixture followed by 1 N HCl (0.5 mL). The resulting mixture is stirred vigorously for 3 h at room temperature. Brine (1 mL) and Et2O (1 mL) are added; the organic layer is separated, and the aqueous layer is extracted with Et2O (3 x 3 mL). The combined organic extracts are dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. Purification of the crude product is performed by flash column chromatography (gradient elution: hexane:Et2O = 50:1 to 5:1) to provide the product.
References
- Iridium-Catalyzed Enantioselective Allylic Substitution of Unstabilized Enolates Derived from α,β-Unsaturated Ketones
Toepassing
C-H Borylation of Arenes
Typical Procedure:
A 25 mL-flask assembled a magnetic stirring bar, a septum inlet, and a condenser is charged with chloro(1,5-cyclooctadiene)iridium(I) dimer (10.1 mg, 0.015 mmol), 2,2’-bipyridyl (4.7 mg, 0.03 mmol), and bis-(pinacolato)diboron (254.0 mg, 1.0 mmol) and then flushed with nitrogen. An arene (60 mmol) is added, and the mixture is stirred at 80 °C for 16 h. The reaction mixture is analyzed by GC and GC mass spectroscopy. The product is extracted with benzene, washed with brine, and dried over MgSO4. Kugelrohr distillation gives analytically pure samples.
References
- Mild iridium-catalyzed borylation of arenes. High turnover numbers, room temperature reactions, and isolation of a potential intermediate
Toepassing
Iridium-catalyzed reaction of alcohols with enones affording 1,3-diketones
Typical procedure (R=H):
A mixture of [IrCl(cod)]2 (34 mg, 0.05 mmol), P(n-Oct)3 (74 mg, 0.2 mmol), i-PrOH (180 mg, 3 mmol), Na2SO3 (50 mg, 0.4 mmol), benzyl alcohol (108 mg, 1 mmol) and 2-cyclohexen-1-one (481 mg, 5 mmol) in p-xylene (1 mL) is stirred at 120 °C for 15 h under an argon atmosphere in a pressure tube. The product is purified by column chromatography on 230-400 mesh silica gel (eluent: hexane/ethyl acetate = 40/1) to give the desired 1,3-diketone (142 mg, 70% yield).
References
Toepassing
Iridium-catalyzed alpha-alkylation of tert-butyl acetate
Typical procedure:
A mixture of [IrCl(cod)]2 (34 mg), PPh3 (39 mg), tert-BuOK (224 mg), n-butanol (74 mg) and tert-butyl acetate (449 mg) in tert-BuOH (1 mL) is stirred at 100 °C for 15 h under Ar. The product (tert-butyl hexanoate) is obtained in 74% yield (estimated using GC), and is isolated by column chromatography on 230-400 mesh silica-gel (eluent: hexane/THF = 50/1) in 62 % yield (107 mg).
References
Toepassing
Selective Synthesis of Diketones and omega-Hydroxy Ketones by [IrCl(cod)]2/PPh3/KOH System
Reference
PubMed Literatuur