Published TCIMAIL newest issue No.198 | Product Document Searching Made Easy by 2D Code! | TCI Chemistry News April 2025 | [Product Highlights] NODAGA Derivatives as... | Various analytical charts can be searched on each product detail page and Product Document Search (The kinds of analytical charts differ by product)
H302 + H312 + H332 : Harmful if swallowed, in contact with skin or if inhaled. H315 : Causes skin irritation. H319 : Causes serious eye irritation.
防范说明
P501 : Dispose of contents/ container to an approved waste disposal plant. P261 : Avoid breathing dust/ fume/ gas/ mist/ vapors/ spray. P270 : Do not eat, drink or smoke when using this product. P271 : Use only outdoors or in a well-ventilated area. P264 : Wash skin thoroughly after handling. P280 : Wear protective gloves/ protective clothing/ eye protection/ face protection. P337 + P313 : If eye irritation persists: Get medical advice/ attention. P305 + P351 + P338 : IF IN EYES: Rinse cautiously with water for several minutes. Remove contact lenses, if present and easy to do. Continue rinsing. P362 + P364 : Take off contaminated clothing and wash it before reuse. P332 + P313 : If skin irritation occurs: Get medical advice/ attention. P301 + P312 + P330 : IF SWALLOWED: Call a POISON CENTER/doctor if you feel unwell. Rinse mouth. P302 + P352 + P312 : IF ON SKIN: Wash with plenty of water.Call a POISON CENTER/doctor if you feel unwell. P304 + P340 + P312 : IF INHALED: Remove person to fresh air and keep comfortable for breathing. Call a POISON CENTER/doctor if you feel unwell.
To a degassed solution of diphenylacetylene (100 mg, 0.561 mmol) and bis(pinacolato)diboron (144 mg, 0.567 mmol) in DMF (0.5 mL) and toluene (0.5 mL) was added Pt(PPh3)4 (2 mg, 0.25 mol%). The reaction mixture was heated to 80 °C for 24 hours. After this time, the reaction was diluted with toluene (10 mL) and washed with saturated aqueous NH4Cl (2 x 10 mL). The organic phase was dried over MgSO4 and concentrated under reduced pressure. Recrystallization from MeOH afforded 1 as a white solid (241 mg, 0.558 mmol, 99%).
Experimenter’s Comments
The reaction mixture was monitored by TLC (CH2Cl2:hexane = 2:1, Rf = 0.45).
To the solution of 3-iodobenzalehyde (1.16 g, 5.00 mmol) in dry DMF (15.0 mL) were added potassium acetate (981 mg, 10.0 mmol), palladium(II) acetate (112 mg, 0.500 mmol, 10 mol%) and bis(pinacolato)diborane (1.27 g, 5.00 mmol). The reaction mixture was stirred at 80 ºC for 7 h. The reaction mixture was cooled to room temperature and quenched with H2O (15 mL) and saturated NH4Cl aq. (10 mL), then the mixture was extracted twice with hexane : EtOAc = 4 : 1. The combined organic layer was washed with H2O (50 mL) and brine (50 mL), dried over Na2SO4, and concentrated under reduced pressure to afford the crude product as a yellow oil. The crude product was purified by column chromatography on silica-gel (hexane → hexane : EtOAc = 1:1) to afford 3-formylphenylboronic acid pinacol ester as a yellow oil (500 mg, 2.15 mmol, 43%).
Experimenter's Comments
(1) DMF was dried over molecular sieves.
(2) Completion of the reaction was confirmed by TLC (hexane : EtOAc = 1 : 1, Rf = 0.30) and GC.
Typical procedure (R = 4-Ph): To a solution of 4-fluorobiphenyl (34.0 mg, 0.2 mmol, 1 eq.), bis(pinacolato)diboron (102 mg, 0.402 mmol, 2.0 eq.), copper iodide (7.6 mg, 0.04 mmol, 0.20 eq.), and cesium fluoride (91.0 mg, 0.6 mmol, 3.0 eq.) in toluene (0.5 mL) is added a solution of bis(1,5-cyclooctadiene)nickel(0) (5.1 mg, 0.02 mmol, 0.10 eq.) and tricyclohexylphosphine (28 mg, 99.8 µmol, 0.50 eq.) in toluene (0.5 mL) at room temperature. After stirring for 1 min at the same temperature, the mixture is heated at 80 °C with stirring for 20 h. After cooling to room temperature, saturated aqueous ammonium chloride (ca. 3 mL) is added to the mixture followed by extraction with EtOAc (ca. 3 mL × 3). The combined organic extract is dried over Na2SO4, and the filtrate is concentrated under reduced pressure. The residue is purified by preparative TLC (solvent: benzene/acetic acid = 20/1) to give 4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)biphenyl (55.6 mg, 0.198 mmol, 99% yield) as a colorless solid.
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
