反应详情

To a solution of (±)-cis-isopropyl [3t-butyldimethylsilyloxy)cyclopentanyl]methylphosphinate (5) (3.2 g, 10 mmol) in anhydrous THF (30 cm3) was added tetrabutylammonium fluoride (11 cm3 of a 1 M solution in THF). The reaction mixture was stirred at room temperature for 12 h at which time the solvent was removed in vacuo. The crude product was purified by short column vacuum chromatography on silica gel (15% ethanol/ethyl acetate); earlier fractions contained the trans isomer, later fractions contained the desired cis (6) isomer which was isolated as a colourless oil (1.8 g, 87%): 1H NMR (300 MHz, CDCl3) δ 1.28 and 1.31 (6H, d, J=6.3 and 6.3 Hz, OCHCH3), 1.45 (3H, d, J=113.2 Hz, PCH3), 1.61-2.32 (6H, m, C(1)—H, C(2)—H, C(2)—H′, C(4)—H, C(4)—H′ and C(5)—H), 4.26 (1H, m, C(3)—H), 4.61 (1H, m, OCHCH3), 13C NMR (75.46 MHz, CDCl3) δ 12.15 and 12.76 (PCH3, d, JPC=90.2 and 89.9 Hz), 23.62 (C(5)), 24.20 and 24.24 (POCCH3, 2×d, 3JPOCC=3.3 Hz), 35.24 and 35.29 (C(2, s), 35.81 and 35.89 (C(1), d, JPC=97.9 and 98.5 Hz), 35.98 and 36.01 (C(4), d, 3JPC=7.2 and 7.5 Hz), 69.11 and 69.12 (POCHCH3, d, 2JPOC=6.9 and 6.9 Hz), 72.8 and 73.3 (C(3), d, 3JPC=4.1 and 4.9 Hz), 31 P NMR (121 MHz, CDCl3) δ 59.4, 59.7, (ESI) 207.1154 (MH+-C9H20O3P requires 207.1150).

1. customwas removed in vacuo
2. customThe crude product was purified by short column vacuum chromatography on silica gel (15% ethanol/ethyl acetate)