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11. In a pressure tube, FeCl3ꢀ6H2O (5 mol %), 1-phenylethanol (5.0 mmol), and
acetylacetone (20.0 mmol) were dissolved in 10 mL of nitromethane. After
stirring for 4 h at 50 °C, the reaction was quenched with water followed by
extraction with dichloromethane. The combined organic layers were dried over
MgSO4 and the solvents were distilled off. Then, the product was purified by
column chromatography (heptanes/ethyl acetate = 1:1).
12. Typical procedure for the synthesis of triarylmethanes 6a–m: To a CH2Cl2 solution
(5 mL) of 5a (236 mg, 1.0 mmol) and 4a (372 mg, 1.1 mmol) was dropwise
added TiCl4 (0.12 mL, 1.1 mmol) at ꢁ78 °C. The reaction mixture was allowed
to warm to 20 °C for 6–12 h. After stirring for additional 2–6 h at 20 °C,
hydrochloric acid (10%, 20 mL) was added. The organic, and the aqueous layers
were separated and the latter was extracted with dichloromethane
(3 ꢂ 25 mL). The combined organic layers were dried (Na2SO4), filtered and
the filtrate was concentrated in vacuo. The residue was purified by
chromatography (silica gel, heptanes/ethyl acetate) to give 6a as a colorless
solid (115 mg, 33%), mp = 153–155 °C. 1H NMR (250 MHz, CDCl3): d 1.98 (s, 3H,
CH3), 2.07 (s, 3H, CH3), 3.79 (s, 3H, OCH3), 5.92 (s, 1H, CH), 6.65 (s, 1H, ArH),
6.99–7.26 (m, 10H, Ph), 10.51 (s, 1H, OH). 13C NMR (250 MHz, CDCl3): d 20.3,
21.7 (CH3), 49.6 (CH), 50.9 (OCH3), 111.7 (C), 116.7, 124.9, 127.1, 128.0 (CHAr),
~
6. Kischel, J.; Mertins, K.; Michalik, D.; Zapf, A.; Beller, M. Adv. Synth. Catal. 2007,
349, 865.
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Angew. Chem. 2006, 118, 807. Angew. Chem., Int. Ed. 2006, 45, 793; (d) Rueping,
M.; Nachtsheim, B. J.; Ieawsuwan, W. Adv. Synth. Catal. 2006, 348, 1033; (e) Yao,
X.; Li, C. J. J. Am. Chem. Soc. 2004, 126, 6884; (f) Yao, X.; Li, C. J. J. Org. Chem.
2005, 70, 5752; (g) Motokura, K.; Fujita, N.; Mori, K.; Mizugaki, T.; Ebitani, K.;
Kaneda, K. Angew. Chem. 2006, 118, 2667. Angew. Chem., Int. Ed. 2006, 45, 2605.
132.1, 139.3, 141.0, 144.3, 158.8, 170.9 (C). IR (KBr):
m ¼ 2987 (w), 1663 (s),
1564 (m), 1435 (m), 1341 (m), 1210 (s), 1069 (s), 857 (m), 801 (s), 719 (s) 696
(s) cmꢁ1. MS (EI, 70 eV): m/z (%) = 346 (M+, 66), 314 (100), 299 (21), 237 (18),
165 (49). HRMS (EI): calcd for C23H22O3 [M]+: 346.156966; found: 346.15635.