Copper(ii)-catalysed addition of O–H bonds to norbornene

Jason G. Taylor, Neil Whittall, King Kuok (Mimi) Hii
2005 Chemical Communications  
Experimental General Remarks. Column chromatography was performed on silica gel (Kieselgel 60,. 1 H and 13 C NMR spectra were acquired using a Bruker DRX 400MHz instrument ( 1 H at 400 MHz and 13 C at 100 MHz). The chemical shifts are reported in δ (ppm) reference to residual protons and 13 C signals to deuterated chloroform. The coupling constants (J) are expressed in Hertz (Hz). Infrared spectra were recorded on a Mattson Instrument Satellite FTIR spectrometer; the samples were prepared as
more » ... her a liquid film between NaCl plates, or pressed into KBr discs. Melting points (uncorrected) were determined using an Electrothermal Gallenhamp apparatus and a calibrated thermometer (± 2 o C). Boiling points were determined by distillation, heating in a Buchi B-580 glass oven under vacuum and measured with a thermometer (± 2 o C). Elemental analysis Service was provided by London Metropolitan University. Mass spectra (MS) were recorded on a Micromass Autospec-Q Mass Spectrometer. All dried solvents were purchased from Sigma-Aldrich and stored under nitrogen atmosphere. All other commercial reagents were used as received. General Procedure for the preparation of norbornyl esters and ethers. Catalytic reactions were conducted in parallel using Radley's 12-placed reaction carousel. For a typical catalytic experiment, reaction tubes are loaded with the catalyst and a Teflon coated stirrer bar, and fitted with a screw cap. The reaction tubes are placed on the reaction carousel and its atmosphere purged under vacuum for 20 minutes and subsequently flushed with nitrogen. Norbornene (144 mg, 1.5 mmol) and the requisite carboxylic acid/alcohol (1.0 mmol) was dissolved in of anhydrous 1,4-dioxane (1 mL) and introduced into the reaction tube through the rubber septum via a syringe needle. The reaction is refluxed at 80ºC by controlled heating using a thermostat for 18 hours. Upon completion the reaction mixture was diluted with Et 2 O (35 mL) and washed with 1M aq. NaHCO 3 (20mL). The layers were separated and the organic layer was dried over Na 2 SO 4 , concentrated under vacuum, and purified by column chromatography (3:1 hexanes/ethylacetate). With the exception of 1c, all oily products were subsequently distilled to furnish analytically pure
doi:10.1039/b509933a pmid:16220185 fatcat:qpq6mtyydjamxg5hbpxjsvbuva