Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270103025757/sq1137sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S0108270103025757/sq1137Isup2.hkl | |
Structure factor file (CIF format) https://doi.org/10.1107/S0108270103025757/sq1137IIsup3.hkl |
CCDC references: 229118; 229119
For the preparation of (I), diene diol (III) was treated with meta-chloroperoxybenzoic acid in CH2Cl2 at room temperature for 36 h, providing the monoepoxide (IV) in 43% yield as a ~1:1 mixture of stereoisomers, along with 40% of unreacted (III). Subjection of (IV) to MeONa in MeOH at reflux for 3 h then provided the crystalline alcohol (I) in 38% yield (m.p. 393–396 K). 1H NMR (CDCl3, 300 MHz): 3.68 (dd, J = 7.9, 2.8 Hz, 1H), 3.73 (AB*X, JAB = 12.6 Hz, JBX = 2.1 Hz, 1H), 3.78 (A*BX, JAB = 12.6 Hz, JAX = 8.1 Hz, 1H), 4.17 (ABX*, ddd, J = 8.1, 3.0, 2.1 Hz, 1H), 4.22 (br d, J = 7.2 Hz, 1H), 4.29 (dd, J = 8.2, 4.5 Hz, 1 H); 4.37 (dd, J = 4.5, 2.8 Hz, 1H), 4.49 (d, J = 11 Hz, 1H), 4.50 (d, J = 11 Hz, 1H), 4.64 (d, J = 11 Hz, 1H), 4.80 (d, J = 11 Hz, 1H), 5.41 (m, 2H), 5.92 (m, 1H). For the preparation of (II), diene diol (III) was treated with I2 and NaHCO3 in CH2Cl2 at 273 K for 1 h, providing the iodoetherification product (V) in 35% yield, along with 60% of unreacted (III). Ozonolysis of (V) at 195 K followed by oxidation of the resulting hemiacetal with tetra-n-propylammonium perruthenate and N-methylmorpholine N-oxide provided the crystalline lactone (II) in 53% yield over two steps (m.p. 389 K). 1H NMR (CDCl3, 300 MHz): 3.21 (dd, J = 10.2, 7.1 Hz, 1H), 3.45 (dd, J = 10.2, 6.4 Hz, 1H), 4.21 (d, J = 5.0 Hz, 1H), 4.22 (dd, J = 6.3, 4.8 Hz, 1H), 4.38 (aq, J = 6.9 Hz, 1H), 4.50 (dd, J = 5.0, 4.0 Hz, 1H), 4.54 (d, J = 11 Hz, 1H), 4.76 (d, J = 11 Hz, 1H), 4.85 (dd, J = 4.5, 4.0 Hz, 1H), 4.91 (ABq, J = 11 Hz, 2H).
Hydroxy H atoms were constrained to an ideal geometry [with Uiso(H) = 1.5Ueq(O)] and allowed to rotate freely about their C—O bonds. All other H atoms were constrained and allowed to ride on their parent C atoms [with Uiso(H) = 1.2Ueq(C)]. In (I), atoms C16, C17, C18, C19, C20 and C21 were fitted to a regular hexagon.
Data collection: SMART (Bruker, 2000–2003) for (I); SMART (Bruker, 2000-2003) for (II). For both compounds, cell refinement: SMART. Data reduction: SAINT? and SHELXTL (Bruker, 2000–2003) for (I); SHELXTL for (II). For both compounds, program(s) used to solve structure: SHELXS97 (Sheldrick, 1990); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL.
C22H26O5 | Dx = 1.271 Mg m−3 |
Mr = 370.43 | Mo Kα radiation, λ = 0.71073 Å |
Orthorhombic, P212121 | Cell parameters from 3927 reflections |
a = 5.5273 (5) Å | θ = 2.0–50.0° |
b = 13.4315 (13) Å | µ = 0.09 mm−1 |
c = 26.074 (2) Å | T = 173 K |
V = 1935.7 (3) Å3 | Needle, colourless |
Z = 4 | 0.50 × 0.30 × 0.30 mm |
F(000) = 792 |
Bruker CCD 1000 area-detector diffractometer | 2262 independent reflections |
Radiation source: fine-focus sealed tube | 1973 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.045 |
ϕ and ω scans | θmax = 26.4°, θmin = 1.7° |
Absorption correction: empirical (using intensity measurements) (SADABS; Blessing, 1995) | h = 0→6 |
Tmin = 0.933, Tmax = 0.974 | k = 0→16 |
10541 measured reflections | l = 0→31 |
Refinement on F2 | Primary atom site location: structure-invariant direct methods |
Least-squares matrix: full | Secondary atom site location: difference Fourier map |
R[F2 > 2σ(F2)] = 0.050 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.135 | H-atom parameters constrained |
S = 1.00 | w = 1/[σ2(Fo2) + (0.1041P)2] where P = (Fo2 + 2Fc2)/3 |
2262 reflections | (Δ/σ)max < 0.001 |
234 parameters | Δρmax = 0.34 e Å−3 |
0 restraints | Δρmin = −0.20 e Å−3 |
C22H26O5 | V = 1935.7 (3) Å3 |
Mr = 370.43 | Z = 4 |
Orthorhombic, P212121 | Mo Kα radiation |
a = 5.5273 (5) Å | µ = 0.09 mm−1 |
b = 13.4315 (13) Å | T = 173 K |
c = 26.074 (2) Å | 0.50 × 0.30 × 0.30 mm |
Bruker CCD 1000 area-detector diffractometer | 2262 independent reflections |
Absorption correction: empirical (using intensity measurements) (SADABS; Blessing, 1995) | 1973 reflections with I > 2σ(I) |
Tmin = 0.933, Tmax = 0.974 | Rint = 0.045 |
10541 measured reflections |
R[F2 > 2σ(F2)] = 0.050 | 0 restraints |
wR(F2) = 0.135 | H-atom parameters constrained |
S = 1.00 | Δρmax = 0.34 e Å−3 |
2262 reflections | Δρmin = −0.20 e Å−3 |
234 parameters |
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. |
x | y | z | Uiso*/Ueq | ||
O1 | −0.1619 (4) | 0.65835 (12) | 0.04537 (7) | 0.0274 (4) | |
O2 | −0.0072 (4) | 0.40576 (12) | 0.07685 (7) | 0.0333 (5) | |
O3 | 0.2720 (3) | 0.61807 (14) | 0.10932 (8) | 0.0294 (5) | |
H3 | 0.2887 | 0.6688 | 0.0908 | 0.044* | |
O4 | 0.0294 (4) | 0.77535 (12) | 0.15874 (6) | 0.0280 (5) | |
O5 | 0.2313 (4) | 0.79140 (13) | 0.05448 (7) | 0.0295 (5) | |
H5 | 0.2910 | 0.8117 | 0.0268 | 0.044* | |
C1 | −0.1262 (5) | 0.57022 (17) | 0.07558 (10) | 0.0235 (6) | |
H1 | −0.2866 | 0.5459 | 0.0881 | 0.028* | |
C2 | 0.0238 (5) | 0.60492 (18) | 0.12125 (10) | 0.0241 (6) | |
H2 | 0.0049 | 0.5578 | 0.1507 | 0.029* | |
C3 | −0.1044 (5) | 0.70289 (17) | 0.13265 (10) | 0.0252 (6) | |
H3A | −0.2558 | 0.6887 | 0.1523 | 0.030* | |
C4 | −0.1730 (5) | 0.74323 (18) | 0.07905 (10) | 0.0241 (6) | |
H4 | −0.3433 | 0.7683 | 0.0801 | 0.029* | |
C5 | −0.0093 (6) | 0.48991 (18) | 0.04322 (10) | 0.0273 (6) | |
H5A | 0.1608 | 0.5096 | 0.0349 | 0.033* | |
C6 | −0.1432 (6) | 0.4688 (2) | −0.00512 (11) | 0.0338 (7) | |
H6 | −0.3048 | 0.4454 | −0.0024 | 0.041* | |
C7 | −0.0529 (7) | 0.4804 (2) | −0.05091 (11) | 0.0403 (8) | |
H7A | 0.1083 | 0.5037 | −0.0550 | 0.048* | |
H7B | −0.1483 | 0.4655 | −0.0802 | 0.048* | |
C8 | 0.1436 (7) | 0.3273 (2) | 0.05918 (13) | 0.0467 (9) | |
H8A | 0.3107 | 0.3518 | 0.0539 | 0.056* | |
H8B | 0.0823 | 0.3011 | 0.0261 | 0.056* | |
C9 | 0.1406 (6) | 0.2469 (2) | 0.09918 (11) | 0.0347 (7) | |
C10 | −0.0486 (6) | 0.1808 (2) | 0.10170 (12) | 0.0380 (7) | |
H10 | −0.1759 | 0.1849 | 0.0773 | 0.046* | |
C11 | −0.0556 (6) | 0.1090 (2) | 0.13904 (12) | 0.0396 (7) | |
H11 | −0.1872 | 0.0636 | 0.1402 | 0.048* | |
C12 | 0.1261 (6) | 0.1024 (2) | 0.17467 (12) | 0.0363 (7) | |
H12 | 0.1203 | 0.0529 | 0.2006 | 0.044* | |
C13 | 0.3157 (6) | 0.1676 (2) | 0.17254 (12) | 0.0387 (7) | |
H13 | 0.4423 | 0.1632 | 0.1971 | 0.046* | |
C14 | 0.3241 (6) | 0.2397 (2) | 0.13501 (13) | 0.0384 (7) | |
H14 | 0.4566 | 0.2847 | 0.1337 | 0.046* | |
C15 | 0.0770 (7) | 0.7492 (2) | 0.21063 (10) | 0.0374 (7) | |
H15A | 0.1530 | 0.6825 | 0.2123 | 0.045* | |
H15B | −0.0758 | 0.7473 | 0.2304 | 0.045* | |
C16 | 0.2433 (3) | 0.82546 (12) | 0.23249 (6) | 0.0277 (6) | |
C17 | 0.2034 (4) | 0.86255 (16) | 0.28153 (6) | 0.0397 (8) | |
H17 | 0.0671 | 0.8408 | 0.3007 | 0.048* | |
C18 | 0.3629 (5) | 0.93140 (16) | 0.30252 (7) | 0.0569 (12) | |
H18 | 0.3357 | 0.9567 | 0.3360 | 0.068* | |
C19 | 0.5623 (4) | 0.96315 (14) | 0.27446 (10) | 0.0636 (12) | |
H19 | 0.6714 | 1.0102 | 0.2888 | 0.076* | |
C20 | 0.6022 (3) | 0.92606 (16) | 0.22541 (9) | 0.0562 (10) | |
H20 | 0.7385 | 0.9478 | 0.2062 | 0.067* | |
C21 | 0.4427 (4) | 0.85722 (15) | 0.20443 (6) | 0.0377 (7) | |
H21 | 0.4699 | 0.8319 | 0.1709 | 0.045* | |
C22 | −0.0111 (5) | 0.82450 (18) | 0.05849 (10) | 0.0244 (6) | |
H22A | −0.0697 | 0.8455 | 0.0243 | 0.029* | |
H22B | −0.0184 | 0.8829 | 0.0816 | 0.029* |
U11 | U22 | U33 | U12 | U13 | U23 | |
O1 | 0.0346 (11) | 0.0227 (8) | 0.0250 (10) | −0.0001 (9) | −0.0071 (8) | 0.0014 (7) |
O2 | 0.0394 (13) | 0.0241 (8) | 0.0364 (11) | 0.0065 (9) | 0.0076 (10) | 0.0032 (8) |
O3 | 0.0206 (10) | 0.0301 (9) | 0.0374 (12) | 0.0013 (8) | −0.0053 (9) | 0.0062 (8) |
O4 | 0.0371 (12) | 0.0267 (8) | 0.0202 (9) | −0.0063 (9) | −0.0032 (9) | 0.0015 (7) |
O5 | 0.0252 (11) | 0.0334 (9) | 0.0298 (11) | 0.0030 (9) | 0.0050 (8) | 0.0096 (8) |
C1 | 0.0240 (15) | 0.0240 (11) | 0.0224 (13) | −0.0019 (11) | −0.0042 (11) | 0.0008 (10) |
C2 | 0.0225 (14) | 0.0249 (12) | 0.0249 (14) | −0.0023 (11) | −0.0019 (11) | 0.0041 (11) |
C3 | 0.0258 (15) | 0.0255 (11) | 0.0244 (13) | −0.0030 (11) | −0.0009 (11) | 0.0034 (10) |
C4 | 0.0227 (14) | 0.0234 (11) | 0.0263 (14) | 0.0043 (11) | −0.0012 (11) | −0.0003 (10) |
C5 | 0.0289 (15) | 0.0249 (11) | 0.0280 (14) | −0.0019 (11) | 0.0002 (12) | 0.0012 (10) |
C6 | 0.0357 (17) | 0.0274 (13) | 0.0382 (17) | −0.0057 (12) | −0.0040 (13) | −0.0067 (12) |
C7 | 0.052 (2) | 0.0359 (14) | 0.0334 (16) | −0.0022 (15) | −0.0034 (15) | −0.0084 (13) |
C8 | 0.053 (2) | 0.0347 (14) | 0.052 (2) | 0.0147 (16) | 0.0200 (18) | 0.0058 (15) |
C9 | 0.0363 (17) | 0.0266 (13) | 0.0411 (17) | 0.0131 (13) | 0.0086 (14) | −0.0037 (12) |
C10 | 0.0307 (16) | 0.0408 (15) | 0.0425 (17) | 0.0051 (14) | −0.0037 (14) | 0.0045 (14) |
C11 | 0.0324 (17) | 0.0376 (15) | 0.0489 (19) | −0.0049 (14) | 0.0007 (15) | 0.0042 (14) |
C12 | 0.0403 (19) | 0.0311 (13) | 0.0375 (17) | 0.0111 (14) | 0.0015 (14) | 0.0029 (13) |
C13 | 0.0353 (17) | 0.0426 (15) | 0.0383 (17) | 0.0121 (15) | −0.0062 (14) | −0.0086 (14) |
C14 | 0.0317 (17) | 0.0312 (13) | 0.0524 (19) | −0.0030 (14) | 0.0029 (15) | −0.0139 (14) |
C15 | 0.049 (2) | 0.0372 (14) | 0.0261 (15) | −0.0117 (15) | −0.0039 (14) | 0.0084 (12) |
C16 | 0.0317 (15) | 0.0252 (11) | 0.0262 (14) | 0.0050 (12) | −0.0034 (12) | 0.0019 (11) |
C17 | 0.0367 (18) | 0.0530 (17) | 0.0293 (16) | 0.0143 (16) | −0.0067 (13) | −0.0071 (14) |
C18 | 0.070 (3) | 0.0490 (18) | 0.052 (2) | 0.032 (2) | −0.030 (2) | −0.0263 (17) |
C19 | 0.069 (3) | 0.0311 (15) | 0.090 (3) | −0.0069 (18) | −0.050 (3) | −0.0006 (19) |
C20 | 0.041 (2) | 0.0542 (19) | 0.073 (3) | −0.0155 (19) | −0.017 (2) | 0.028 (2) |
C21 | 0.0340 (17) | 0.0361 (14) | 0.0430 (17) | 0.0030 (14) | 0.0027 (15) | 0.0088 (13) |
C22 | 0.0275 (15) | 0.0241 (11) | 0.0215 (13) | 0.0052 (11) | −0.0026 (11) | 0.0023 (10) |
O1—C1 | 1.435 (3) | C9—C10 | 1.373 (4) |
O1—C4 | 1.440 (3) | C9—C14 | 1.382 (4) |
O2—C8 | 1.421 (3) | C10—C11 | 1.371 (4) |
O2—C5 | 1.431 (3) | C10—H10 | 0.9500 |
O3—C2 | 1.418 (3) | C11—C12 | 1.371 (4) |
O3—H3 | 0.8400 | C11—H11 | 0.9500 |
O4—C3 | 1.399 (3) | C12—C13 | 1.366 (5) |
O4—C15 | 1.423 (3) | C12—H12 | 0.9500 |
O5—C22 | 1.416 (3) | C13—C14 | 1.378 (4) |
O5—H5 | 0.8400 | C13—H13 | 0.9500 |
C1—C5 | 1.514 (4) | C14—H14 | 0.9500 |
C1—C2 | 1.524 (4) | C15—C16 | 1.490 (3) |
C1—H1 | 1.0000 | C15—H15A | 0.9900 |
C2—C3 | 1.524 (4) | C15—H15B | 0.9900 |
C2—H2 | 1.0000 | C16—C17 | 1.3900 |
C3—C4 | 1.546 (4) | C16—C21 | 1.3900 |
C3—H3A | 1.0000 | C17—C18 | 1.3900 |
C4—C22 | 1.510 (4) | C17—H17 | 0.9500 |
C4—H4 | 1.0000 | C18—C19 | 1.3900 |
C5—C6 | 1.489 (4) | C18—H18 | 0.9500 |
C5—H5A | 1.0000 | C19—C20 | 1.3900 |
C6—C7 | 1.303 (4) | C19—H19 | 0.9500 |
C6—H6 | 0.9500 | C20—C21 | 1.3900 |
C7—H7A | 0.9500 | C20—H20 | 0.9500 |
C7—H7B | 0.9500 | C21—H21 | 0.9500 |
C8—C9 | 1.501 (4) | C22—H22A | 0.9900 |
C8—H8A | 0.9900 | C22—H22B | 0.9900 |
C8—H8B | 0.9900 | ||
C1—O1—C4 | 108.91 (17) | C10—C9—C8 | 120.4 (3) |
C8—O2—C5 | 113.1 (2) | C14—C9—C8 | 120.8 (3) |
C2—O3—H3 | 109.5 | C11—C10—C9 | 120.7 (3) |
C3—O4—C15 | 112.85 (19) | C11—C10—H10 | 119.7 |
C22—O5—H5 | 109.5 | C9—C10—H10 | 119.7 |
O1—C1—C5 | 109.9 (2) | C10—C11—C12 | 120.4 (3) |
O1—C1—C2 | 104.55 (19) | C10—C11—H11 | 119.8 |
C5—C1—C2 | 114.9 (2) | C12—C11—H11 | 119.8 |
O1—C1—H1 | 109.1 | C13—C12—C11 | 119.5 (3) |
C5—C1—H1 | 109.1 | C13—C12—H12 | 120.2 |
C2—C1—H1 | 109.1 | C11—C12—H12 | 120.2 |
O3—C2—C3 | 112.7 (2) | C12—C13—C14 | 120.3 (3) |
O3—C2—C1 | 113.2 (2) | C12—C13—H13 | 119.8 |
C3—C2—C1 | 99.4 (2) | C14—C13—H13 | 119.8 |
O3—C2—H2 | 110.4 | C13—C14—C9 | 120.3 (3) |
C3—C2—H2 | 110.4 | C13—C14—H14 | 119.9 |
C1—C2—H2 | 110.4 | C9—C14—H14 | 119.9 |
O4—C3—C2 | 116.7 (2) | O4—C15—C16 | 107.9 (2) |
O4—C3—C4 | 109.00 (19) | O4—C15—H15A | 110.1 |
C2—C3—C4 | 103.9 (2) | C16—C15—H15A | 110.1 |
O4—C3—H3A | 109.0 | O4—C15—H15B | 110.1 |
C2—C3—H3A | 109.0 | C16—C15—H15B | 110.1 |
C4—C3—H3A | 109.0 | H15A—C15—H15B | 108.4 |
O1—C4—C22 | 109.3 (2) | C17—C16—C21 | 120.0 |
O1—C4—C3 | 105.25 (18) | C17—C16—C15 | 120.05 (17) |
C22—C4—C3 | 115.4 (2) | C21—C16—C15 | 119.92 (17) |
O1—C4—H4 | 108.9 | C18—C17—C16 | 120.0 |
C22—C4—H4 | 108.9 | C18—C17—H17 | 120.0 |
C3—C4—H4 | 108.9 | C16—C17—H17 | 120.0 |
O2—C5—C6 | 111.9 (2) | C17—C18—C19 | 120.0 |
O2—C5—C1 | 102.99 (19) | C17—C18—H18 | 120.0 |
C6—C5—C1 | 113.3 (2) | C19—C18—H18 | 120.0 |
O2—C5—H5A | 109.5 | C20—C19—C18 | 120.0 |
C6—C5—H5A | 109.5 | C20—C19—H19 | 120.0 |
C1—C5—H5A | 109.5 | C18—C19—H19 | 120.0 |
C7—C6—C5 | 124.2 (3) | C19—C20—C21 | 120.0 |
C7—C6—H6 | 117.9 | C19—C20—H20 | 120.0 |
C5—C6—H6 | 117.9 | C21—C20—H20 | 120.0 |
C6—C7—H7A | 120.0 | C20—C21—C16 | 120.0 |
C6—C7—H7B | 120.0 | C20—C21—H21 | 120.0 |
H7A—C7—H7B | 120.0 | C16—C21—H21 | 120.0 |
O2—C8—C9 | 107.6 (2) | O5—C22—C4 | 111.1 (2) |
O2—C8—H8A | 110.2 | O5—C22—H22A | 109.4 |
C9—C8—H8A | 110.2 | C4—C22—H22A | 109.4 |
O2—C8—H8B | 110.2 | O5—C22—H22B | 109.4 |
C9—C8—H8B | 110.2 | C4—C22—H22B | 109.4 |
H8A—C8—H8B | 108.5 | H22A—C22—H22B | 108.0 |
C10—C9—C14 | 118.8 (3) | ||
C4—O1—C1—C5 | −155.8 (2) | C1—C5—C6—C7 | 118.9 (3) |
C4—O1—C1—C2 | −32.0 (3) | C5—O2—C8—C9 | 176.8 (3) |
O1—C1—C2—O3 | −77.7 (3) | O2—C8—C9—C10 | 80.5 (3) |
C5—C1—C2—O3 | 42.8 (3) | O2—C8—C9—C14 | −97.6 (3) |
O1—C1—C2—C3 | 42.0 (3) | C14—C9—C10—C11 | 0.0 (4) |
C5—C1—C2—C3 | 162.5 (2) | C8—C9—C10—C11 | −178.2 (3) |
C15—O4—C3—C2 | −69.5 (3) | C9—C10—C11—C12 | 0.3 (5) |
C15—O4—C3—C4 | 173.3 (2) | C10—C11—C12—C13 | −0.4 (5) |
O3—C2—C3—O4 | −36.2 (3) | C11—C12—C13—C14 | 0.2 (4) |
C1—C2—C3—O4 | −156.3 (2) | C12—C13—C14—C9 | 0.1 (4) |
O3—C2—C3—C4 | 83.8 (3) | C10—C9—C14—C13 | −0.2 (4) |
C1—C2—C3—C4 | −36.3 (2) | C8—C9—C14—C13 | 178.0 (3) |
C1—O1—C4—C22 | 132.4 (2) | C3—O4—C15—C16 | 173.5 (2) |
C1—O1—C4—C3 | 7.9 (3) | O4—C15—C16—C17 | 137.1 (2) |
O4—C3—C4—O1 | 144.1 (2) | O4—C15—C16—C21 | −45.0 (3) |
C2—C3—C4—O1 | 19.0 (3) | C21—C16—C17—C18 | 0.0 |
O4—C3—C4—C22 | 23.5 (3) | C15—C16—C17—C18 | 178.0 (2) |
C2—C3—C4—C22 | −101.6 (2) | C16—C17—C18—C19 | 0.0 |
C8—O2—C5—C6 | 71.5 (3) | C17—C18—C19—C20 | 0.0 |
C8—O2—C5—C1 | −166.5 (2) | C18—C19—C20—C21 | 0.0 |
O1—C1—C5—O2 | −174.8 (2) | C19—C20—C21—C16 | 0.0 |
C2—C1—C5—O2 | 67.6 (3) | C17—C16—C21—C20 | 0.0 |
O1—C1—C5—C6 | −53.8 (3) | C15—C16—C21—C20 | −178.0 (2) |
C2—C1—C5—C6 | −171.3 (2) | O1—C4—C22—O5 | −59.0 (3) |
O2—C5—C6—C7 | −125.3 (3) | C3—C4—C22—O5 | 59.3 (3) |
D—H···A | D—H | H···A | D···A | D—H···A |
O3—H3···O5 | 0.84 | 1.93 | 2.741 (3) | 163 |
O5—H5···O1i | 0.84 | 1.94 | 2.754 (3) | 162 |
Symmetry code: (i) x+1/2, −y+3/2, −z. |
C21H21IO5 | F(000) = 480 |
Mr = 480.28 | Dx = 1.566 Mg m−3 |
Monoclinic, P21 | Mo Kα radiation, λ = 0.71073 Å |
a = 6.0077 (7) Å | Cell parameters from 2146 reflections |
b = 15.4106 (14) Å | θ = 2.0–50.0° |
c = 11.0654 (13) Å | µ = 1.60 mm−1 |
β = 96.066 (2)° | T = 296 K |
V = 1018.72 (19) Å3 | Needle, colourless |
Z = 2 | 0.40 × 0.30 × 0.30 mm |
Bruker CCD 1000 area-detector diffractometer | 2969 independent reflections |
Radiation source: fine-focus sealed tube | 2480 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.018 |
ϕ and ω scans | θmax = 26.3°, θmin = 2.3° |
Absorption correction: empirical (using intensity measurements) (SADABS; Blessing, 1995) | h = −6→7 |
Tmin = 0.567, Tmax = 0.645 | k = −8→18 |
4977 measured reflections | l = −13→13 |
Refinement on F2 | Secondary atom site location: difference Fourier map |
Least-squares matrix: full | Hydrogen site location: inferred from neighbouring sites |
R[F2 > 2σ(F2)] = 0.028 | H-atom parameters constrained |
wR(F2) = 0.065 | w = 1/[σ2(Fo2) + (0.0326P)2] where P = (Fo2 + 2Fc2)/3 |
S = 1.03 | (Δ/σ)max < 0.001 |
2969 reflections | Δρmax = 0.52 e Å−3 |
244 parameters | Δρmin = −0.27 e Å−3 |
1 restraint | Absolute structure: Flack H D (1983), Acta Cryst. A39, 876-881 |
Primary atom site location: structure-invariant direct methods | Absolute structure parameter: −0.02 (2) |
C21H21IO5 | V = 1018.72 (19) Å3 |
Mr = 480.28 | Z = 2 |
Monoclinic, P21 | Mo Kα radiation |
a = 6.0077 (7) Å | µ = 1.60 mm−1 |
b = 15.4106 (14) Å | T = 296 K |
c = 11.0654 (13) Å | 0.40 × 0.30 × 0.30 mm |
β = 96.066 (2)° |
Bruker CCD 1000 area-detector diffractometer | 2969 independent reflections |
Absorption correction: empirical (using intensity measurements) (SADABS; Blessing, 1995) | 2480 reflections with I > 2σ(I) |
Tmin = 0.567, Tmax = 0.645 | Rint = 0.018 |
4977 measured reflections |
R[F2 > 2σ(F2)] = 0.028 | H-atom parameters constrained |
wR(F2) = 0.065 | Δρmax = 0.52 e Å−3 |
S = 1.03 | Δρmin = −0.27 e Å−3 |
2969 reflections | Absolute structure: Flack H D (1983), Acta Cryst. A39, 876-881 |
244 parameters | Absolute structure parameter: −0.02 (2) |
1 restraint |
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. |
x | y | z | Uiso*/Ueq | ||
I | 0.54530 (4) | 0.31222 (3) | 0.55513 (2) | 0.07157 (12) | |
O1 | 0.2583 (6) | 0.3727 (2) | 0.3021 (3) | 0.0676 (9) | |
O2 | 0.1573 (5) | 0.2594 (2) | 0.0896 (3) | 0.0550 (8) | |
O3 | 0.5039 (4) | 0.44003 (19) | 0.1315 (3) | 0.0554 (8) | |
O4 | 0.4830 (5) | 0.2770 (2) | 0.0138 (3) | 0.0675 (9) | |
O5 | −0.0054 (6) | 0.1788 (2) | 0.2772 (3) | 0.0653 (8) | |
C1 | 0.1356 (7) | 0.3935 (3) | 0.1900 (4) | 0.0508 (10) | |
H1 | 0.0400 | 0.4447 | 0.1944 | 0.061* | |
C2 | 0.0040 (5) | 0.3110 (5) | 0.1532 (3) | 0.0505 (8) | |
H2 | −0.1357 | 0.3235 | 0.1022 | 0.061* | |
C3 | −0.0375 (7) | 0.2688 (3) | 0.2726 (4) | 0.0557 (11) | |
H3 | −0.1890 | 0.2828 | 0.2918 | 0.067* | |
C4 | 0.1373 (5) | 0.3126 (5) | 0.3668 (3) | 0.0515 (8) | |
H4 | 0.0596 | 0.3436 | 0.4273 | 0.062* | |
C5 | 0.2970 (7) | 0.4013 (3) | 0.0947 (4) | 0.0488 (10) | |
H5 | 0.2243 | 0.4325 | 0.0241 | 0.059* | |
C6 | 0.3306 (6) | 0.3079 (5) | 0.0608 (3) | 0.0494 (9) | |
C7 | 0.4894 (8) | 0.5315 (3) | 0.1538 (5) | 0.0703 (14) | |
H7A | 0.3506 | 0.5447 | 0.1874 | 0.084* | |
H7B | 0.4918 | 0.5633 | 0.0783 | 0.084* | |
C8 | 0.6834 (7) | 0.5571 (3) | 0.2410 (4) | 0.0560 (12) | |
C9 | 0.7090 (9) | 0.5196 (4) | 0.3539 (5) | 0.0719 (14) | |
H9 | 0.6013 | 0.4807 | 0.3752 | 0.086* | |
C10 | 0.8901 (11) | 0.5381 (4) | 0.4361 (5) | 0.0846 (17) | |
H10 | 0.9068 | 0.5115 | 0.5120 | 0.102* | |
C11 | 1.0484 (11) | 0.5976 (4) | 0.4040 (6) | 0.0867 (18) | |
H11 | 1.1743 | 0.6097 | 0.4577 | 0.104* | |
C12 | 1.0192 (10) | 0.6379 (4) | 0.2947 (6) | 0.0794 (16) | |
H12 | 1.1222 | 0.6794 | 0.2753 | 0.095* | |
C13 | 0.8365 (11) | 0.6180 (4) | 0.2106 (6) | 0.0660 (16) | |
H13 | 0.8182 | 0.6454 | 0.1353 | 0.079* | |
C14 | −0.1731 (9) | 0.1296 (4) | 0.2050 (5) | 0.0721 (14) | |
H14A | −0.2068 | 0.1560 | 0.1255 | 0.086* | |
H14B | −0.3097 | 0.1269 | 0.2444 | 0.086* | |
C15 | −0.0774 (8) | 0.0407 (3) | 0.1932 (5) | 0.0551 (13) | |
C16 | 0.1154 (8) | 0.0289 (4) | 0.1351 (5) | 0.0685 (14) | |
H16 | 0.1841 | 0.0767 | 0.1037 | 0.082* | |
C17 | 0.2049 (8) | −0.0518 (4) | 0.1236 (5) | 0.0741 (15) | |
H17 | 0.3330 | −0.0581 | 0.0840 | 0.089* | |
C18 | 0.1094 (10) | −0.1235 (4) | 0.1692 (5) | 0.0732 (15) | |
H18 | 0.1719 | −0.1782 | 0.1617 | 0.088* | |
C19 | −0.0821 (9) | −0.1129 (4) | 0.2269 (5) | 0.0707 (14) | |
H19 | −0.1500 | −0.1612 | 0.2576 | 0.085* | |
C20 | −0.1733 (9) | −0.0324 (4) | 0.2394 (5) | 0.0618 (14) | |
H20 | −0.3011 | −0.0267 | 0.2794 | 0.074* | |
C21 | 0.3001 (9) | 0.2495 (4) | 0.4299 (5) | 0.0735 (14) | |
H21A | 0.3753 | 0.2184 | 0.3697 | 0.088* | |
H21B | 0.2188 | 0.2074 | 0.4735 | 0.088* |
U11 | U22 | U33 | U12 | U13 | U23 | |
I | 0.06916 (17) | 0.0762 (2) | 0.06637 (17) | 0.0028 (3) | −0.00675 (11) | 0.0060 (3) |
O1 | 0.081 (2) | 0.068 (2) | 0.0506 (18) | −0.0253 (18) | −0.0070 (16) | 0.0043 (17) |
O2 | 0.0504 (18) | 0.055 (2) | 0.0604 (19) | −0.0089 (16) | 0.0076 (15) | −0.0097 (15) |
O3 | 0.0429 (15) | 0.0475 (19) | 0.074 (2) | −0.0033 (13) | −0.0012 (14) | −0.0037 (15) |
O4 | 0.0513 (17) | 0.067 (2) | 0.086 (2) | −0.0020 (14) | 0.0128 (15) | −0.0166 (17) |
O5 | 0.079 (2) | 0.049 (2) | 0.065 (2) | −0.0107 (17) | −0.0048 (16) | 0.0003 (16) |
C1 | 0.054 (2) | 0.039 (3) | 0.058 (3) | 0.005 (2) | 0.003 (2) | 0.002 (2) |
C2 | 0.0370 (15) | 0.055 (2) | 0.058 (2) | 0.004 (4) | −0.0002 (14) | −0.002 (4) |
C3 | 0.049 (2) | 0.058 (3) | 0.060 (3) | −0.002 (2) | 0.005 (2) | 0.002 (2) |
C4 | 0.0517 (18) | 0.051 (2) | 0.0538 (19) | 0.003 (4) | 0.0135 (15) | −0.008 (4) |
C5 | 0.038 (2) | 0.054 (3) | 0.053 (2) | 0.000 (2) | −0.0023 (18) | 0.004 (2) |
C6 | 0.0440 (18) | 0.055 (3) | 0.0477 (18) | −0.006 (4) | −0.0026 (15) | −0.003 (4) |
C7 | 0.062 (3) | 0.051 (3) | 0.094 (4) | 0.001 (2) | −0.011 (2) | 0.004 (3) |
C8 | 0.060 (3) | 0.039 (3) | 0.070 (3) | 0.004 (2) | 0.005 (2) | −0.006 (2) |
C9 | 0.081 (3) | 0.056 (3) | 0.080 (4) | −0.006 (3) | 0.013 (3) | −0.008 (3) |
C10 | 0.120 (5) | 0.058 (4) | 0.073 (4) | −0.002 (3) | −0.005 (3) | −0.012 (3) |
C11 | 0.099 (4) | 0.061 (4) | 0.094 (4) | −0.004 (3) | −0.023 (3) | −0.025 (3) |
C12 | 0.083 (4) | 0.051 (3) | 0.103 (4) | −0.022 (3) | 0.004 (3) | −0.015 (3) |
C13 | 0.086 (4) | 0.034 (3) | 0.077 (4) | −0.010 (3) | 0.004 (3) | 0.000 (3) |
C14 | 0.066 (3) | 0.065 (4) | 0.084 (4) | −0.014 (3) | 0.005 (3) | −0.011 (3) |
C15 | 0.056 (3) | 0.052 (3) | 0.054 (3) | −0.011 (2) | −0.006 (2) | −0.006 (2) |
C16 | 0.059 (3) | 0.065 (4) | 0.083 (4) | −0.019 (3) | 0.012 (3) | −0.011 (3) |
C17 | 0.058 (3) | 0.087 (5) | 0.076 (4) | 0.001 (3) | 0.001 (2) | −0.014 (3) |
C18 | 0.089 (4) | 0.066 (4) | 0.060 (3) | 0.012 (3) | −0.016 (3) | 0.001 (3) |
C19 | 0.082 (3) | 0.063 (4) | 0.065 (3) | −0.007 (3) | 0.004 (3) | 0.013 (3) |
C20 | 0.067 (3) | 0.066 (4) | 0.053 (3) | −0.006 (3) | 0.008 (2) | 0.002 (3) |
C21 | 0.075 (3) | 0.056 (3) | 0.088 (4) | −0.004 (3) | −0.001 (3) | 0.003 (3) |
I—C21 | 2.143 (5) | C9—C10 | 1.373 (8) |
O1—C1 | 1.412 (5) | C9—H9 | 0.9300 |
O1—C4 | 1.417 (7) | C10—C11 | 1.395 (9) |
O2—C6 | 1.347 (6) | C10—H10 | 0.9300 |
O2—C2 | 1.454 (6) | C11—C12 | 1.354 (9) |
O3—C5 | 1.400 (5) | C11—H11 | 0.9300 |
O3—C7 | 1.434 (6) | C12—C13 | 1.396 (8) |
O4—C6 | 1.199 (5) | C12—H12 | 0.9300 |
O5—C3 | 1.401 (6) | C13—H13 | 0.9300 |
O5—C14 | 1.434 (6) | C14—C15 | 1.497 (8) |
C1—C5 | 1.510 (6) | C14—H14A | 0.9700 |
C1—C2 | 1.529 (8) | C14—H14B | 0.9700 |
C1—H1 | 0.9800 | C15—C20 | 1.388 (7) |
C2—C3 | 1.517 (6) | C15—C16 | 1.395 (7) |
C2—H2 | 0.9800 | C16—C17 | 1.367 (8) |
C3—C4 | 1.553 (6) | C16—H16 | 0.9300 |
C3—H3 | 0.9800 | C17—C18 | 1.365 (8) |
C4—C21 | 1.499 (8) | C17—H17 | 0.9300 |
C4—H4 | 0.9800 | C18—C19 | 1.383 (7) |
C5—C6 | 1.506 (9) | C18—H18 | 0.9300 |
C5—H5 | 0.9800 | C19—C20 | 1.369 (8) |
C7—C8 | 1.486 (6) | C19—H19 | 0.9300 |
C7—H7A | 0.9700 | C20—H20 | 0.9300 |
C7—H7B | 0.9700 | C21—H21A | 0.9700 |
C8—C9 | 1.370 (7) | C21—H21B | 0.9700 |
C8—C13 | 1.380 (7) | ||
C1—O1—C4 | 110.1 (3) | C8—C9—C10 | 121.4 (5) |
C6—O2—C2 | 110.8 (4) | C8—C9—H9 | 119.3 |
C5—O3—C7 | 113.6 (3) | C10—C9—H9 | 119.3 |
C3—O5—C14 | 114.7 (4) | C9—C10—C11 | 118.8 (6) |
O1—C1—C5 | 108.5 (3) | C9—C10—H10 | 120.6 |
O1—C1—C2 | 104.6 (4) | C11—C10—H10 | 120.6 |
C5—C1—C2 | 103.5 (3) | C12—C11—C10 | 120.1 (6) |
O1—C1—H1 | 113.2 | C12—C11—H11 | 119.9 |
C5—C1—H1 | 113.2 | C10—C11—H11 | 119.9 |
C2—C1—H1 | 113.2 | C11—C12—C13 | 120.9 (6) |
O2—C2—C3 | 111.0 (5) | C11—C12—H12 | 119.6 |
O2—C2—C1 | 104.3 (3) | C13—C12—H12 | 119.6 |
C3—C2—C1 | 104.6 (3) | C8—C13—C12 | 119.0 (6) |
O2—C2—H2 | 112.1 | C8—C13—H13 | 120.5 |
C3—C2—H2 | 112.1 | C12—C13—H13 | 120.5 |
C1—C2—H2 | 112.1 | O5—C14—C15 | 106.2 (4) |
O5—C3—C2 | 114.9 (5) | O5—C14—H14A | 110.5 |
O5—C3—C4 | 109.0 (4) | C15—C14—H14A | 110.5 |
C2—C3—C4 | 103.7 (4) | O5—C14—H14B | 110.5 |
O5—C3—H3 | 109.7 | C15—C14—H14B | 110.5 |
C2—C3—H3 | 109.7 | H14A—C14—H14B | 108.7 |
C4—C3—H3 | 109.7 | C20—C15—C16 | 117.5 (5) |
O1—C4—C21 | 108.4 (3) | C20—C15—C14 | 122.2 (5) |
O1—C4—C3 | 107.0 (3) | C16—C15—C14 | 120.3 (5) |
C21—C4—C3 | 113.1 (6) | C17—C16—C15 | 121.0 (5) |
O1—C4—H4 | 109.4 | C17—C16—H16 | 119.5 |
C21—C4—H4 | 109.4 | C15—C16—H16 | 119.5 |
C3—C4—H4 | 109.4 | C18—C17—C16 | 121.1 (5) |
O3—C5—C6 | 110.0 (3) | C18—C17—H17 | 119.4 |
O3—C5—C1 | 116.5 (3) | C16—C17—H17 | 119.4 |
C6—C5—C1 | 102.1 (4) | C17—C18—C19 | 118.5 (5) |
O3—C5—H5 | 109.3 | C17—C18—H18 | 120.7 |
C6—C5—H5 | 109.3 | C19—C18—H18 | 120.7 |
C1—C5—H5 | 109.3 | C20—C19—C18 | 120.9 (5) |
O4—C6—O2 | 121.7 (6) | C20—C19—H19 | 119.5 |
O4—C6—C5 | 128.1 (5) | C18—C19—H19 | 119.5 |
O2—C6—C5 | 110.2 (4) | C19—C20—C15 | 120.8 (5) |
O3—C7—C8 | 108.4 (4) | C19—C20—H20 | 119.6 |
O3—C7—H7A | 110.0 | C15—C20—H20 | 119.6 |
C8—C7—H7A | 110.0 | C4—C21—I | 112.2 (4) |
O3—C7—H7B | 110.0 | C4—C21—H21A | 109.2 |
C8—C7—H7B | 110.0 | I—C21—H21A | 109.2 |
H7A—C7—H7B | 108.4 | C4—C21—H21B | 109.2 |
C9—C8—C13 | 119.7 (5) | I—C21—H21B | 109.2 |
C9—C8—C7 | 119.0 (5) | H21A—C21—H21B | 107.9 |
C13—C8—C7 | 121.3 (5) |
Experimental details
(I) | (II) | |
Crystal data | ||
Chemical formula | C22H26O5 | C21H21IO5 |
Mr | 370.43 | 480.28 |
Crystal system, space group | Orthorhombic, P212121 | Monoclinic, P21 |
Temperature (K) | 173 | 296 |
a, b, c (Å) | 5.5273 (5), 13.4315 (13), 26.074 (2) | 6.0077 (7), 15.4106 (14), 11.0654 (13) |
α, β, γ (°) | 90, 90, 90 | 90, 96.066 (2), 90 |
V (Å3) | 1935.7 (3) | 1018.72 (19) |
Z | 4 | 2 |
Radiation type | Mo Kα | Mo Kα |
µ (mm−1) | 0.09 | 1.60 |
Crystal size (mm) | 0.50 × 0.30 × 0.30 | 0.40 × 0.30 × 0.30 |
Data collection | ||
Diffractometer | Bruker CCD 1000 area-detector diffractometer | Bruker CCD 1000 area-detector diffractometer |
Absorption correction | Empirical (using intensity measurements) (SADABS; Blessing, 1995) | Empirical (using intensity measurements) (SADABS; Blessing, 1995) |
Tmin, Tmax | 0.933, 0.974 | 0.567, 0.645 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 10541, 2262, 1973 | 4977, 2969, 2480 |
Rint | 0.045 | 0.018 |
(sin θ/λ)max (Å−1) | 0.625 | 0.624 |
Refinement | ||
R[F2 > 2σ(F2)], wR(F2), S | 0.050, 0.135, 1.00 | 0.028, 0.065, 1.03 |
No. of reflections | 2262 | 2969 |
No. of parameters | 234 | 244 |
No. of restraints | 0 | 1 |
H-atom treatment | H-atom parameters constrained | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.34, −0.20 | 0.52, −0.27 |
Absolute structure | ? | Flack H D (1983), Acta Cryst. A39, 876-881 |
Absolute structure parameter | ? | −0.02 (2) |
Computer programs: SMART (Bruker, 2000–2003), SMART (Bruker, 2000-2003), SMART, SAINT? and SHELXTL (Bruker, 2000–2003), SHELXTL, SHELXS97 (Sheldrick, 1990), SHELXL97 (Sheldrick, 1997).
D—H···A | D—H | H···A | D···A | D—H···A |
O3—H3···O5 | 0.84 | 1.93 | 2.741 (3) | 163 |
O5—H5···O1i | 0.84 | 1.94 | 2.754 (3) | 162 |
Symmetry code: (i) x+1/2, −y+3/2, −z. |
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The chiral molecules (1S,2R,3S,4R,5R)-4-Benzyloxy-2-[1-(benzyloxy)allyl]-5-hydroxymethyl- 2,3,4,5-tetrahydrofuran-3-ol, (I), and (3R,5S,6S,7S,8S)-3,6-bis(benzyloxy)-5-iodomethyl-2,3,4,5- tetrahydrofuro[3,2-b]furan-2-one, (II), have been prepared from the same precursor, namely (3S,4R,5R,6S)-3,6-bis(benzyloxy)-octa-1,7-diene-4,5-diol, (III), and structurally characterized during the course of our work toward the synthesis of natural products related to marine sponge extracts. Diene diol (III) was also used to prepare a Conduritol E derivative that we have reported previously (Clark et al., 2001). We compare here the conformational properties of these two tetrahydrofuran ring-bearing compounds, (I) and (II).
The absolute stereochemical assignment of (I) [R (C1), S (C2), R (C3), R (C4) and S (C5)] is based solely on knowledge of the synthesis, while the chiral centers in (II) were unequivocally assigned as S (C1), S (C2), S (C3), S (C4) and R (C5) from the crystallographic data. Crystallographic studies verify the expectation that the five-membered O1—C1–C4 heterocycles in both structures have the same relative stereochemistry, with all substituents in a cis arrangement with respect to one another. In the case of (II), this all-cis arrangement forces the substituents on atoms C3, C4 and C5 to be directed toward the concave face of the bicyclic ring system.
Although the bond distances in (I) and (II) are typical, several bond angles of the O1—C1—C2—C3—C4 ring system in (I) exhibit appreciable differences from the corresponding parameters in (II). The C3—C2—C1 [99.4 (2)°], O1—C4—C3 [105.25 (18)°], and C1—O1—C4 [108.91 (17)°] angles in (I) differ significantly from the related C3—C2—C1 [104.6 (4)°], O1—C4—C3 [107.0 (3)°], and C1—O1—C4 [110.1 (3)°] angles in (II). The presence of a second ring in (II), which is fused to the tetrahydrofuranyl ring of interest at the C1 and C2 positions, causes widening of these bond angles, with concomitant reduction of the C5—C1—C2 and C1—C2—O2 angles.
The stereochemical properties of the O1—C1–C4 heterocycles of (I) and (II) were further characterized by conformational analysis according to Cremer & Pople (1975) by using the program RING5 (Guzei, 2003). The conformation of the O1—C1–C4 ring system in (I) is characterized by the puckering amplitude, q2, of 0.410 Å and phase angle, ϕ2, of 63.36°. The latter value indicates that the ring conformation is intermediate between the twisted 3T2 and envelope 3E, in which atom C2 would be the flap atom. A similar conformation intermediate between twisted 4T3 and envelope 4E is observed for the O2—C6—C5—C1—C2 ring in (II), which is characterized by a q2 value of 0.296 Å and a phase angle of 279.61°. This ring does not deviate quite as much from planarity, as revealed by the puckering amplitude. The other five-membered ring in (II), O1—C1–C4, has an envelope conformation, E2, with atom C1 occupying the flap position [q2=0.295 Å and ϕ2=37.96°].
The primary contributors to the adopted conformations of the O1—C1–C4 rings of the two structures are the presence of hydrogen-bonding interactions in (I) and a bicyclic ring system in (II). In (I), an intramolecular O3—H3.·O5 hydrogen bond is observed Table 1. ?The corresponding values for 155 compounds with 192 similar hydrogen bonds reported to the Cambridge Structural Database (CSD; Allen, 2002) are 2.73 (8) Å and 161 (6)°? This distance is indicative of a reasonably strong hydrogen bond and could affect the bond angles and ring conformation mentioned earlier. In the lattice of (I), intermolecular O5—H5.·O1[x + 1/2, −y + 3/2, −z] hydrogen-bonding interactions form a series of one-dimensional chains in the a direction (Table 1). The relevant values for 398 compounds with 429 similar hydrogen bonds (CSD) are 2.82 (6) Å and 166 (8)°. Both types of hydrogen-bonding interactions may influence the positioning of the flap atom C2 in (I). In contrast, (II) does not contain hydrogen bonds but instead contains a bicyclic ring system. Steric repulsion and torsional strain of the adjoined rings in (II) are probably minimized when atom C1 is the flap atom of the O1—C1–C4 heterocycle.
In order to compare the observed ring conformations with theoretical data, density-functional theory calculations were performed on simplified analogs of (I) and (II), referred to as (Ia) and (IIa). In both molecules, the phenyl rings were replaced by methyl groups, and the I atom was replaced with an H in (IIa), in order to reduce computational time. The geometry optimizations were performed at the B3LYP/6–311++G** level (Gaussian98). The calculated C—O bond distances agree with experimental data within 0.006 Å in (I) and 0.01 Å in (II), while the calculated C—C distances for both molecules differ by up to 0.026 Å from the experimental parameters. The puckering coordinates for the O1—C1–C4 ring in (Ia) (q2=0.391 Å and ϕ2=66.14°) are in excellent agreement with the experimental data producing a similar conformation, i.e. intermediate between 2T3 and E3 with atom C2 in the flap position of the envelope configuration.
The results of conformational analysis of (IIa) differ considerably from those obtained for (II), apparently because of the influence of the I atom on the lattice packing. While the energy required to affect torsion angles in the lattice may not exceed several kcal mol−1 it is instructive to appreciate the changes that a large atom can introduce. Thus, ring O1—C1–C4 in (IIa) (q2=0.374 Å and ϕ2=345.84°) is in a twisted conformation, 1T5, and ring O2—C6—C5—C1—C2 (q2=0.203 Å and ϕ2=83.55°) adopts a conformation intermediate between 3E and 3T4, with atom C5 in the flap position. For the two rings, both the conformations and the amplitudes are very different from the corresponding values in the parent compound (III)? (see above), indicating that the lattice forces in the solid-state structure of (II) play a sinificant role and considerably affect the molecular configuration.