反应详情

温度

80 °C

To a flame dried round-bottomed flask, [Rh(COD)Cl]2 (1.7 mg, 0.0035 mmol), (S)—(R)-PPF-PtBu2 (3.8 mg, 0.0069 mmol) and 1 (100 mg, 0.694 mmol) were added followed by addition of THF (2.5 mL) and 2-bromophenol (0.40 mL, 3.47 mmol). The mixture was heated at 80° C. for 24 hours, then poured into diethyl ether and extracted 3 times with 10% aqueous sodium hydroxide solution. The aqueous extracts were combined and back-extracted three times with diethyl ether. The combined ether extracts were washed with brine and dried with anhydrous sodium sulfate. The solvents were removed in vacuo, yielding a solid which was purified by flash chromatography on silica gel (5% ethyl acetate in hexanes) as a white crystalline solid 13 (75 mg, 37%). The ee was determined to be 81% by HPLC analysis on a CHIRALCEL OD column, λ=486 nm. Retention times in 1.5% isopropanol in hexanes were 22.8 min and 32.1 min (major). Rf=0.44 on silica (20% ethyl acetate in hexanes); mp 120-122° C. (Et2O); [α]25D=+254° (c=9.2, CHCl3). IR (KBr, cm−1) 3341 (br), 3071 (w), 2884 (w), 1581 (m), 1472 (s), 1358 (m), 1237 (s), 1028 (s), 987 (s), 780 (s), 689 (m), 569 (m); 1H NMR (400 MHz, CDCl3): δ 7.67 (1H, d J=6.8 Hz), 7.58 (1H, dd, J=1.5, 7.9 Hz), 7.33-7.23 (3H, m), 7.14-7.12 (1H, m), 6.95(1H, dd, J=1.1, 8.2 Hz), 6.92-6.87 (1H, m), 6.52 (1H, dd, J=2.0, 9.9 Hz), 6.06 (1H, dd, J=1.8, 9.9 Hz), 5.32 (1H, d, J=11.0 Hz), 5.10 (1H, ddd, J=2.0, 2.0, 11.0 Hz), 2.85 (1H, d, J=3.2 Hz). 13C NMR (400 MHz, CDCl3): δ 154.3, 135.4, 133.6, 131.8, 129.1, 128.6, 128.3, 128.0, 126.4, 126.0, 124.9, 122.9, 115.6, 113.5, 82.2, 72.5. HRMS calculated for (M−H2O)+ (C16H11OBr): 297.9993. Found: 297.9976.

1. extractionextracted 3 times with 10% aqueous sodium hydroxide solution
2. extractionback-extracted three times with diethyl ether
3. washThe combined ether extracts were washed with brine
4. dry with materialdried with anhydrous sodium sulfate
5. customThe solvents were removed in vacuo
6. customyielding a solid which
7. customwas purified by flash chromatography on silica gel (5% ethyl acetate in hexanes) as a white crystalline solid 13 (75 mg, 37%)