Supporting Information for Chemoselective Metal-free Aerobic Alcohol Oxidation in Lignin Synthesis of Lignin Model Compounds S1 Iii. Catalyst Screening and Optimization Data S3 1-oxidation with Traditional Chemical Oxidants S3 2-catalytic Aerobic Oxidatio
Supporting Information for Chemoselective Metal-free Aerobic Alcohol Oxidation in Lignin Synthesis of Lignin Model Compounds S1 Iii. Catalyst Screening and Optimization Data S3 1-oxidation with Traditional Chemical Oxidants S3 2-catalytic Aerobic Oxidatio
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通讯作者：
A. Rahimi;A. Azarpira;H. Kim;J. Ralph;S. Stahl
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作者：
A. Rahimi;A. Azarpira;H. Kim;J. Ralph;S. Stahl
I.一般考虑。除非另有说明，否则所有市售化合物均购买并按原样使用。使用前，将溶剂在氧化铝柱上干燥;然而，本文所述的催化反应不需要纯化和干燥商业溶剂（注意：经常添加水作为助溶剂）。用Varian 300 MHz或Bruker AC-400和500 MHz获得1H和13 C NMR谱，其中溶剂峰或四甲基硅烷用作内标。多重性通过使用以下缩写来描述：s =单峰，d =双峰，t =三重峰，q =四重峰，sept =七重峰和m =多重峰。使用SiliaFlash® P60（二氧化硅，粒度40-63 μm，230-400目）进行快速色谱。使用具有可重复使用的高性能二氧化硅柱（RediSep® Rf Gold Silica，20-40 µm球形颗粒）的CombiFlash Rf®系统进行一些色谱分析。藜芦醇和2-甲氧基-1，2-二苯基乙醇，购自Sigma-Aldrich。制备2-芳氧基-1-苯基乙醇（7 c-7 e）的一般程序：根据文献程序，由相应的苯酚和2-溴苯乙酮以两步合成这些底物。将2-溴苯乙酮（5 mmol，0.990g）加入到K2 CO 3（7.5mmol，1.036g）和愈创木酚（6.25mmol，0.776g）在丙酮（50 mL）中的搅拌溶液中。将反应混合物在回流温度下搅拌5小时，然后将其过滤并在真空下浓缩。将残余物通过柱色谱法用己烷：乙酸乙酯（3：1）纯化。将所得化合物（3.5mmol，0.847g）溶解于THF：H2O（5：1）的混合物（25 mL）中，并分批加入硼氢化钠（7 mmol，0.26g）以保持气体的温和放出。然后，将混合物在室温下搅拌6小时。将反应混合物用饱和NH 4Cl水溶液（50 mL）淬灭并用30 mL水稀释。用乙酸乙酯（3 × 30）萃取水性部分。将有机部分合并，经MgSO 4干燥，过滤并在真空下浓缩。将残余物通过柱色谱法用己烷：乙酸乙酯（2：1）纯化。2-（2-甲氧基苯基）氧基-1-苯乙醇（7 c）：光谱数据与文献中报告的数据一致。
I. General Considerations. All commercially available compounds were purchased and used as received, unless otherwise noted. Solvents were dried over an alumina column prior to use; however, purification and drying of commercial solvents is not required for the catalytic reactions described here (note: frequently water is added as a cosolvent). 1 H and 13 C NMR spectra were obtained with a Varian 300 MHz, or Bruker AC-400 and 500 MHz with the solvent peak or tetramethylsilane used as the internal reference. Multiplicities are described by using the following abbreviations: s = singlet, d = doublet, t = triplet, q = quartet, sept = septet and m = multiplet. Flash chromatography was performed using SiliaFlash® P60 (Silicycle, particle size 40-63 µm, 230-400 mesh). Some chromatography was carried out using a CombiFlash Rf® system with reusable high performance silica columns (RediSep® Rf Gold Silica, 20-40 µm spherical particles). Veratryl alcohol and 2-methoxy-1,2-diphenylethanol, which were purchased from Sigma-Aldrich. General procedure for preparation of 2-aryloxy-1-phenylethanols (7c-7e): These substrates were synthesized in two-step from the corresponding phenol and 2-bromoacetophenone according to literature procedure. 1 2-Bromoacetophenone (5 mmol, 0.990 g) was added to a stirred solution of K 2 CO 3 (7.5 mmol, 1.036 g) and guaiacol (6.25 mmol, 0.776 g) in acetone (50 mL). The reaction mixture was stirred at reflux temperature for 5 h, after which it was filtered off and concentrated under vacuum. The residue was purified by column chromatography with hexane : ethyl acetate (3:1). The resulting compound (3.5 mmol, 0.847 g) was dissolved in the mixture of THF : H 2 O (5:1) (25 mL), and sodium borohydride (7 mmol, 0.26 g) was added portionwise to maintain a gentle evolution of gas. Then, the mixture was stirred for 6 h at room temperature. The reaction mixture was quenched with saturated aqueous NH 4 Cl (50 mL) and diluted with 30 mL water. The aqueous portion was extracted with ethyl acetate (3 × 30). The organic parts were combined, dried over MgSO 4 , filtered and concentrated under vacuum. The residue was purified by column chromatography with hexane : ethyl acetate (2:1). 2-(2-Methoxyphenyl)oxy-1-phenethanol (7c): Spectral data are consistent with those reported in the literature.