Compound 12

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InChIKey JZLUHDLWPNIVQL-AFDKUVFXSA-N

Synthetic procedure: See article for the definitive version of this procedure and for full experimental details.

Crude diol 11 (100% yield assumed from RCM reactions, 34.5 mmol ) in CH₂Cl₂ (ca. 250 mL) was cooled to 0 °C. 19.2 mL (138.0 mmol, 4 eq.) NEt₃ was added followed by a dropwise addition of 7.51 mL (103.5 mmol, 3 eq.) SOCl₂ and stirred at 0 °C for 1 h. The reaction mixture was diluted with CHCl₃ (400 mL), washed with H₂O (3 × 150 mL) and brine (400 mL), dried over MgSO₄, filtered and concentrated in vacuo. The crude product was purified by flash column chromatography (hexanes:EtOAc = 3:1) to yield 9.48 g (29.3 mmol, 85% over 2 steps) sulfite 12 as a mixture of diastereomers in ratio of (54:46). TLC (hexanes:EtOAc = 2:1), R_f = 0.81 (UV, CAM). ¹H NMR (CDCl₃, 300 MHz): δ= 7.36 (brs, 5H), 6.19–5.94 (m, 2H), 5.63–5.43 (m, 1H), 5.39–5.05 (m, 2H), 5.04–4.69 (m, 1H), 4.45–4.12 (m, 2H), 3.31–2.91 (m, 1H), 2.82–2.60 (m, 1H), 2.43–2.21 (m, 1H), 2.19–1.93 (m, 1H). ¹³C NMR (CDCl₃, 75 MHz): δ= 155.6, 136.2, 136.0, 132.7, 132.1, 131.6, 130.3, 129.7, 129.2, 128.7, 128.6, 128.4, 128.3, 128.2, 128.1, 128.0, 84.1, 83.1, 81.7, 81.6, 80.8, 80.5, 78.8, 78.1, 67.9, 67.8, 67.7, 48.1, 47.9, 47.7, 47.7, 47.2, 47.1, 46.3, 29.8, 29.5, 29.2, 29.0. IR (Diamond-ATR, neat) ν_max: 2947, 1695, 1463, 1417, 1211, 963, 740, 698 cm^-1. [α]²⁵ _D – 7.2° (c= 0.42, CHCl₃). HRMS (EI) calcd for C₁₅H₁₇NO₅S: 323.0827; found: 323.0826.