Reaktionsschritte
The product was prepared, by General procedure T using 98 mg (0.55 mmol) Cy2BH, 68 μL (0.55 mmol) 3,3-dimethyl-1-butyne, 0.78 mL (1.55 mmol, 2.0 M in hexanes) Et2Zn, 4.8 mg (0.02 mmol) (−)-MIB, 59 μL (0.50 mmol) p-tolualdehyde, 100 μL, (0.10 mmol, 1.0 M in hexanes) Ti(OiPr)4, and 21 μL (0.10 mmol) (+)-DIPT. The crude product was purified by column chromatography (5% ethyl acetate in hexanes) to afford the title compound in 85% yield (93 mg, 0.42 mmol). threo-diastereomer: White solid. m.p.: 36-39° C.; [α]D20=−40.0 (c=0.26, CHCl3); 1H NMR (CDCl3, 500 MHz): δ 0.81 (s, 9H), 2.28 (s, 3H), 2.35 (br d, 1H, J=3.9 Hz), 2.78 (d, 1H, J=2.2 Hz), 2.97 (dd, 1H, J=5.5, 2.2 Hz), 4.39 (br t, 1H), 7.10 (d, 2H, J=7.8 Hz), and 7.22 (d, 2H, J=7.9 Hz) ppm; 13C{1H} NMR (CDCl3, 125 MHz): δ 21.1, 25.7, 30.6, 59.4, 65.1, 74.1, 125.9, 129.2, 137.5, and 137.7 ppm; IR (film): 3416, 3095, 2957, 2867, 1614, 1514, 1482, 1463, 1417, 1393, 1365, 1260, and 1239 cm−1; HRMS-CI m/z 203.1431 [(M−OH)+; calcd for C14H19O: 203.1436]. erythro-diastereomer: White solid. m.p.: 65-68° C.; [α]D20=−58.2 (c=0.57, CHCl3); 1H NMR (CDCl3, 500 MHz): δ 0.82 (s, 9H), 2.16 (br s, 1H), 2.28 (s, 3H), 2.95 (d, 1H, J=2.1 Hz), 2.97 (t, 1H, J=2.7 Hz), 4.76 (br s, 1H), 7.10 (d, 2H, J=7.7 Hz), and 7.19 (d, 2H, J=8.0 Hz) ppm; 13C{1H} NMR (CDCl3, 125 MHz): □ 21.2, 25.8, 30.4, 58.3, 62.8, 71.1, 126.5, 129.2, 136.8, and 137.9 ppm; IR (film): 3418, 3018, 2965, 2923, 2867, 1919, 1515, 1478, 1458, 1412, 1381, and 1322 cm−1; HRMS-CI m/z 203.1431 [(M−OH)+; calcd for C14H19O: 203.1436].
