Crystal structures of (±)-(1SR,5SR,6SR,7SR,10SR,11SR,13RS,14SR)-13-hy­droxy-7-meth­oxy­meth­oxy-11,15,18,18-tetra­methyl-3-oxo-2,4-dioxa­tetra­cyclo­[12.3.1.01,5.06,11]octa­dec-15-en-10-yl benzoate, its 13-epimer and 13-one derivative

. 2015 Apr 9;71(Pt 5):466–472. doi: 10.1107/S2056989015006854

Experimental. M.p. 510.7–512.2 K (not corrected); IR (film) 2934, 1804, 1718, 1689, 1668, 1272, 1230, 1108, 1058, 732, 713 cm^-1; ¹H NMR (500 MHz, CDCl₃) δ (p.p.m.) 8.05–8.98 (m, 2H), 7.62–7.56 (m, 1H), 7.49–7.43 (m, 2H), 5.73 (bs, 1H), 4.79 (d, J = 6.9 Hz, 1H), 4.76 (dd, J = 11.0, 4.0 Hz, 1H), 4.60 (d, J = 6.9 Hz, 1H), 4.22 (d, J = 3.4 Hz, 1H), 3.62 (ddd, J = 10.6, 10.3, 5.2 Hz, 1H), 3.37 (s, 3H), 3.00 (bd, J = 17.0 Hz, 1H), 2.61 (d, J = 10.9 Hz, 1H), 2.51 (d, J = 17.0 Hz, 1H), 2.47 (s, 1H), 2.42–2.35 (m, 1H), 2.33 (dd, J = 10.6, 3.4 Hz, 1H), 2.13 (d, J = 10.9 Hz, 1H), 1.95–1.88 (m, 1H), 1.71 (s, 3H), 1.71–1.52 (m, 2H), 1.27 (s, 3H), 1.17 (s, 3H), 1.16 (s, 3H); ¹³C NMR (125 MHz, CDCl₃) δ (p.p.m.) 211.2 (C), 165.9 (C), 153.7 (C), 135.8 (C), 133.5 (CH), 129.8 (C), 129.7 (CH), 128.7 (CH), 122.6 (CH), 97.8 (CH₂), 87.0 (C), 79.3 (CH), 79.0 (CH), 74.7 (CH), 65.7 (CH), 56.0 (CH₃), 51.2 (CH₂), 48.0 (CH), 47.1 (C), 44.1 (C), 31.9 (CH₂), 31.2 (CH₂), 25.1 (CH₃), 24.6 (CH₃), 24.6 (CH₂), 19.3 (CH₃), 12.3 (CH₃); LRMS (EI) m/z 512 (M⁺, 5%), 346 (9), 302 (7), 121 (28), 105 (100), 77 (55); HRMS (EI) m/z calcd for C₂₉H₃₆O₈⁺ [M]⁺ 512.2410, found 514.2408.

Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes.

Refinement. Refinement of F² against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F², conventional R-factors R are based on F, with F set to zero for negative F². The threshold expression of F² > σ(F²) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F² are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger.Problematic two reflections with |I(obs)-I(calc)|/σW(I) greater than 10 (1 1 0 and 11 4 3) have been omitted in the final refinement.