Compound 32

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InChIKey QWDFMLJGEQZYJX-YFCFIHESSA-N

Compound data: NMR

Compound data: Crystallographic data

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

General procedure 1 (GP1): A premixed aqueous solution of NaOH (2 M) and H₂O₂ (30%) (2:1, 6 mL) was added dropwise to a solution of the boronic ester (1.00 eq.) in THF (4 mL) at 0 °C. The reaction mixture was vigorously stirred at room temperature for 4–16 h. The reaction mixture was diluted with water (10 mL) and Et₂O (10 mL). The layers were separated and the aqueous phase extracted with Et₂O (3 × 10 mL). The combined organic layers were washed with brine, dried over MgSO₄ and concentrated under reduced pressure. Residual pinacol was sublimed under high vacuum for 18 h to give the desired product. Boronic ester 18 (70 mg, 0.13 mmol, 1.00 eq.) was oxidised according to GP1 outlined above. The crude residue was purified by flash column chromatography (CH₂Cl₂:Et₂O 90:10) to give diol 32 (39 mg, 95%) as a white solid. . TLC: R_f = 0.26 (CH₂Cl₂:Et₂O 90:10). m.p.: 136 – 140 °C (n-hexane). ¹H NMR (400 MHz, Chloroform-d): δ 3.65 (2H, dq, J = 8.1, 6.1 Hz, H2), 1.75 (2H, dqd, J = 8.5, 6.8, 3.4 Hz, H6), 1.57 (2H, dqd, J = 8.1, 7.0, 3.4 Hz, H4), 1.55 – 1.39 (4H, m, H8 & H10), 1.28 (2H, br. s, H1), 1.19 (6H, d, J = 6.1 Hz, H3), 0.77 (6H, d, J = 6.8 Hz, H7), 0.76 – 0.73 (12H, m, H9 & H11), 0.72 (6H, d, J = 7.0 Hz, H5) ppm. ¹³C NMR (126 MHz, Chloroform-d): δ 70.0 (C2), 41.1 (C4), 35.5 (CH), 35.2 (CH), 34.7 (C6), 21.6 (C3), 12.0 (CH₃), 11.9 (CH₃), 11.8 (CH₃), 10.5 (CH₃) ppm. HRMS (m/z): (ESI⁺) calc’d. for C₂₀H₄₂NaO₂ [M+Na]⁺: 337.3077; found 337.3088. IR (ν_max): 3307, 2968, 2919, 2879, 1454, 1382, 1084, 1053, 918 cm⁻¹. [α]_D²³: −5 (CHCl₃, c = 1.0).