Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536807022854/rz2139sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S1600536807022854/rz2139Isup2.hkl |
CCDC reference: 652132
The synthesis of (I) was carried out under the conditions of the oxidative removal of the benzyl protecting group (Oikawa et al., 1982). To a solution of (2S,3S,4R)-Methyl-4-(benzyloxymethyl)-2-hydroxy-3-methylhex-5-enoate (200 mg, 0.72 mmol, 1.0 eq) in dry dichloromethane (4 ml) and pH 7 buffer (1 ml) was added 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (0.49 g, 2.16 mmol, 3.0 eq) at 273 K. The orange mixture was stirred at room temperature for 3 days and filtered through a pad of celite and MgSO4. The solvents were removed under reduced pressure. Flash chromatography (isohexane/ethyl acetate 20/1 to 10/1) afforded (I) (78 mg, 0.49 mmol, 69%) as colourless crystals. Single crystals of (I) were obtained by vapor diffusion recrystallization technique from isohexane and ethyl acetate to yield colourless cuboids: mp 357 K; Rf = 0.5 (isohexane/ethyl acetate 1/1); 1H NMR (400 MHz, CDCl3, δ) 0.96 (d, J = 7.0 Hz, 3H), 2.42–2.46 (m, 1H), 2.93–2.95 (m, 1H), 3.28 (br. s, 1H), 4.20–4.35 (m, 1H + 2H), 5.10–5.21 (m, 2H), 5.68 (ddd, J = 17.4, 10.5, 6.9 Hz, 1H); 13C NMR (100 MHz, CDCl3, δ) 7.4 (CH3), 36.0 (CH), 40.8 (CH), 69.9 (CH2), 71.4 (CH), 118.5 (CH2=), 133.9 (CH=), 174.2 (C═O); IR (in substance) ν 3250–3500, 2920, 1740 cm-1; Anal. Calcd. for C8H12O3: C, 61.5; H, 7.7. Found: C, 61.7; H, 7.7; [α]25D +18.1 (c 0.42, CHCl3).
H atoms were refined isotropically. In the absence of significant anomalous scattering effects, Friedel pairs were merged in the final refinement.
The title compound, (I), was synthesized to proof the relative configuration in the projected total synthesis of curvicollides A—C using a catalytic asymmetric Claisen rearrangement (Abraham, Körner et al., 2004; Abraham, Körner & Hiersemann, 2004) and a diastereoselective reduction with K-Selectride (Körner & Hiersemann, 2006). In order to verify the assumed relative configuration of methyl-4-(benzyloxymethyl)-2-hydroxy-3-methylhex-5-enoate (the preparation of this intermediate will be described elsewhere; Körner & Hiersemann, 2007), the δ-lactone, (I), was prepared. Fig. 1 shows that the relative configuration of C2, C3 and C4 is as expected. The configuration of the chiral C atoms in (I) (C2 S, C3 S and C4 R) were assigned based on the previously described stereochemical course of the catalytic asymmetric Claisen rearrangement (CAC) using the chiral Lewis acid [Cu{(S,S)-tert-Butyl-box}] (H2O)2(SbF6)2 (Evans et al., 1999). In the crystal the molecules are linked via a bifurcated O—H ··· O hydrogen bridge (Table 1) and a chain of molecules is formed along the a axis.
For related literature, see: Abraham, Körner & Hiersemann (2004); Abraham, Körner et al. (2004); Evans et al. (1999); Körner & Hiersemann (2006, 2007); Oikawa et al. (1982).
Data collection: COLLECT (Nonius, 1998); cell refinement: DENZO and SCALEPACK (Otwinowski & Minor, 1997); data reduction: DENZO and SCALEPACK; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: SHELXTL-Plus (Sheldrick, 1991); software used to prepare material for publication: SHELXL97 and PLATON (Spek, 2003).
Fig. 1. The molecular structure of the title compound, showing the labelling of all non-H atoms. Displacement ellipsoids are shown at the 30% probability level. |
C8H12O3 | F(000) = 336 |
Mr = 156.18 | Dx = 1.329 Mg m−3 |
Orthorhombic, P212121 | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: P 2ac 2ab | Cell parameters from 7057 reflections |
a = 5.4490 (5) Å | θ = 3.3–27.5° |
b = 6.4489 (5) Å | µ = 0.10 mm−1 |
c = 22.2203 (14) Å | T = 173 K |
V = 780.82 (11) Å3 | Block, colourless |
Z = 4 | 0.45 × 0.40 × 0.40 mm |
Nonius KappaCCD area-detector diffractometer | 727 reflections with I > 2σ(I) |
Radiation source: fine-focus sealed tube | Rint = 0.026 |
Graphite monochromator | θmax = 27.5°, θmin = 3.3° |
Detector resolution: 19 vertical, 18 horizontal pixels mm-1 | h = −7→7 |
289 frames via ω rotation (Δω = 1°) and two times 20 s per frame (three sets at different κ–angles) scans | k = −8→8 |
7057 measured reflections | l = −28→28 |
1075 independent reflections |
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)] = 0.029 | All H-atom parameters refined |
wR(F2) = 0.058 | w = 1/[σ2(Fo2) + (0.0305P)2] where P = (Fo2 + 2Fc2)/3 |
S = 0.90 | (Δ/σ)max < 0.001 |
1075 reflections | Δρmax = 0.15 e Å−3 |
149 parameters | Δρmin = −0.14 e Å−3 |
0 restraints | Extinction correction: SHELXL97 (Sheldrick, 1997), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4 |
Primary atom site location: structure-invariant direct methods | Extinction coefficient: 0.048 (5) |
C8H12O3 | V = 780.82 (11) Å3 |
Mr = 156.18 | Z = 4 |
Orthorhombic, P212121 | Mo Kα radiation |
a = 5.4490 (5) Å | µ = 0.10 mm−1 |
b = 6.4489 (5) Å | T = 173 K |
c = 22.2203 (14) Å | 0.45 × 0.40 × 0.40 mm |
Nonius KappaCCD area-detector diffractometer | 727 reflections with I > 2σ(I) |
7057 measured reflections | Rint = 0.026 |
1075 independent reflections |
R[F2 > 2σ(F2)] = 0.029 | 0 restraints |
wR(F2) = 0.058 | All H-atom parameters refined |
S = 0.90 | Δρmax = 0.15 e Å−3 |
1075 reflections | Δρmin = −0.14 e Å−3 |
149 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 | 0.5199 (2) | 0.8726 (2) | 0.82549 (5) | 0.0360 (4) | |
O2 | 0.6965 (2) | 0.6799 (2) | 0.89410 (6) | 0.0410 (4) | |
O3 | 0.3787 (2) | 0.7650 (2) | 0.98007 (5) | 0.0361 (4) | |
H3O | 0.249 (4) | 0.769 (4) | 1.0033 (10) | 0.058 (7)* | |
C1 | 0.5252 (3) | 0.7878 (3) | 0.88106 (7) | 0.0296 (5) | |
C2 | 0.3065 (3) | 0.8247 (3) | 0.92142 (7) | 0.0272 (4) | |
H2 | 0.178 (3) | 0.732 (3) | 0.9067 (7) | 0.028 (5)* | |
C3 | 0.2162 (3) | 1.0476 (3) | 0.91739 (7) | 0.0256 (5) | |
H3 | 0.064 (3) | 1.055 (3) | 0.9395 (6) | 0.021 (4)* | |
C4 | 0.1557 (3) | 1.0900 (3) | 0.85078 (8) | 0.0262 (4) | |
H4 | 0.041 (3) | 0.986 (3) | 0.8395 (7) | 0.024 (5)* | |
C5 | 0.3836 (3) | 1.0619 (3) | 0.81287 (8) | 0.0330 (5) | |
H5A | 0.338 (3) | 1.055 (2) | 0.7706 (8) | 0.025 (4)* | |
H5B | 0.502 (3) | 1.182 (3) | 0.8212 (7) | 0.030 (5)* | |
C6 | 0.3998 (4) | 1.1984 (4) | 0.94473 (9) | 0.0358 (5) | |
H6A | 0.415 (3) | 1.169 (3) | 0.9876 (8) | 0.033 (5)* | |
H6B | 0.561 (4) | 1.184 (3) | 0.9246 (8) | 0.046 (6)* | |
H6C | 0.335 (4) | 1.347 (4) | 0.9409 (8) | 0.050 (6)* | |
C7 | 0.0438 (3) | 1.3007 (3) | 0.84232 (8) | 0.0297 (5) | |
H7 | −0.073 (3) | 1.337 (3) | 0.8724 (7) | 0.033 (5)* | |
C8 | 0.0979 (4) | 1.4381 (3) | 0.80057 (9) | 0.0360 (5) | |
H8A | 0.020 (3) | 1.575 (3) | 0.8003 (7) | 0.034 (5)* | |
H8B | 0.225 (4) | 1.415 (3) | 0.7692 (9) | 0.050 (6)* |
U11 | U22 | U33 | U12 | U13 | U23 | |
O1 | 0.0363 (7) | 0.0428 (9) | 0.0288 (7) | 0.0135 (7) | 0.0068 (6) | 0.0009 (6) |
O2 | 0.0334 (8) | 0.0448 (9) | 0.0448 (8) | 0.0126 (8) | 0.0043 (6) | 0.0038 (7) |
O3 | 0.0334 (7) | 0.0450 (10) | 0.0300 (7) | 0.0077 (7) | 0.0038 (6) | 0.0099 (7) |
C1 | 0.0289 (10) | 0.0290 (12) | 0.0308 (10) | 0.0010 (10) | −0.0019 (8) | −0.0027 (9) |
C2 | 0.0262 (9) | 0.0285 (11) | 0.0269 (9) | 0.0007 (9) | −0.0012 (8) | 0.0017 (8) |
C3 | 0.0218 (9) | 0.0284 (12) | 0.0267 (9) | −0.0006 (9) | 0.0045 (8) | 0.0006 (8) |
C4 | 0.0231 (9) | 0.0282 (12) | 0.0274 (9) | 0.0000 (9) | −0.0006 (8) | −0.0011 (9) |
C5 | 0.0315 (11) | 0.0398 (14) | 0.0278 (10) | 0.0082 (11) | −0.0002 (9) | 0.0023 (10) |
C6 | 0.0391 (12) | 0.0372 (14) | 0.0311 (11) | −0.0045 (11) | −0.0003 (9) | −0.0027 (10) |
C7 | 0.0264 (10) | 0.0348 (12) | 0.0278 (9) | 0.0028 (9) | 0.0012 (8) | −0.0002 (9) |
C8 | 0.0400 (12) | 0.0348 (14) | 0.0333 (11) | 0.0043 (11) | −0.0018 (10) | 0.0012 (11) |
O1—C1 | 1.351 (2) | C4—C5 | 1.512 (3) |
O1—C5 | 1.456 (2) | C4—H4 | 0.952 (18) |
O2—C1 | 1.200 (2) | C5—H5A | 0.973 (17) |
O3—C2 | 1.415 (2) | C5—H5B | 1.024 (19) |
O3—H3O | 0.88 (2) | C6—H6A | 0.974 (18) |
C1—C2 | 1.510 (2) | C6—H6B | 0.99 (2) |
C2—C3 | 1.522 (3) | C6—H6C | 1.02 (2) |
C2—H2 | 0.977 (19) | C7—C8 | 1.316 (3) |
C3—C6 | 1.522 (3) | C7—H7 | 0.952 (18) |
C3—C4 | 1.541 (2) | C8—H8A | 0.98 (2) |
C3—H3 | 0.964 (17) | C8—H8B | 1.00 (2) |
C4—C7 | 1.502 (3) | ||
C1—O1—C5 | 121.78 (14) | C5—C4—H4 | 108.0 (10) |
C2—O3—H3O | 108.0 (14) | C3—C4—H4 | 105.5 (10) |
O2—C1—O1 | 118.19 (16) | O1—C5—C4 | 114.33 (15) |
O2—C1—C2 | 124.20 (16) | O1—C5—H5A | 106.3 (10) |
O1—C1—C2 | 117.49 (16) | C4—C5—H5A | 109.5 (10) |
O3—C2—C1 | 106.53 (14) | O1—C5—H5B | 106.0 (9) |
O3—C2—C3 | 113.67 (15) | C4—C5—H5B | 109.2 (9) |
C1—C2—C3 | 111.67 (16) | H5A—C5—H5B | 111.6 (13) |
O3—C2—H2 | 110.0 (10) | C3—C6—H6A | 109.0 (11) |
C1—C2—H2 | 105.7 (10) | C3—C6—H6B | 110.2 (12) |
C3—C2—H2 | 109.0 (10) | H6A—C6—H6B | 110.3 (15) |
C2—C3—C6 | 111.57 (15) | C3—C6—H6C | 109.7 (12) |
C2—C3—C4 | 107.06 (14) | H6A—C6—H6C | 106.9 (16) |
C6—C3—C4 | 114.26 (17) | H6B—C6—H6C | 110.7 (19) |
C2—C3—H3 | 107.0 (11) | C8—C7—C4 | 127.34 (18) |
C6—C3—H3 | 109.4 (10) | C8—C7—H7 | 118.7 (12) |
C4—C3—H3 | 107.2 (9) | C4—C7—H7 | 113.9 (12) |
C7—C4—C5 | 111.85 (16) | C7—C8—H8A | 120.9 (10) |
C7—C4—C3 | 111.58 (15) | C7—C8—H8B | 123.2 (13) |
C5—C4—C3 | 109.76 (15) | H8A—C8—H8B | 115.8 (17) |
C7—C4—H4 | 109.9 (10) | ||
C5—O1—C1—O2 | −155.30 (18) | C2—C3—C4—C7 | 175.08 (14) |
C5—O1—C1—C2 | 28.4 (2) | C6—C3—C4—C7 | −60.9 (2) |
O2—C1—C2—O3 | 17.4 (3) | C2—C3—C4—C5 | −60.4 (2) |
O1—C1—C2—O3 | −166.52 (16) | C6—C3—C4—C5 | 63.7 (2) |
O2—C1—C2—C3 | 142.05 (19) | C1—O1—C5—C4 | −31.6 (3) |
O1—C1—C2—C3 | −41.9 (2) | C7—C4—C5—O1 | 171.65 (15) |
O3—C2—C3—C6 | 52.0 (2) | C3—C4—C5—O1 | 47.2 (2) |
C1—C2—C3—C6 | −68.52 (19) | C5—C4—C7—C8 | 11.9 (3) |
O3—C2—C3—C4 | 177.73 (15) | C3—C4—C7—C8 | 135.3 (2) |
C1—C2—C3—C4 | 57.18 (19) |
D—H···A | D—H | H···A | D···A | D—H···A |
O3—H3O···O2i | 0.88 (2) | 2.32 (2) | 2.9881 (18) | 133.0 (17) |
O3—H3O···O3i | 0.88 (2) | 2.06 (2) | 2.8713 (8) | 153.1 (19) |
Symmetry code: (i) x−1/2, −y+3/2, −z+2. |
Experimental details
Crystal data | |
Chemical formula | C8H12O3 |
Mr | 156.18 |
Crystal system, space group | Orthorhombic, P212121 |
Temperature (K) | 173 |
a, b, c (Å) | 5.4490 (5), 6.4489 (5), 22.2203 (14) |
V (Å3) | 780.82 (11) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 0.10 |
Crystal size (mm) | 0.45 × 0.40 × 0.40 |
Data collection | |
Diffractometer | Nonius KappaCCD area-detector |
Absorption correction | – |
No. of measured, independent and observed [I > 2σ(I)] reflections | 7057, 1075, 727 |
Rint | 0.026 |
(sin θ/λ)max (Å−1) | 0.649 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.029, 0.058, 0.90 |
No. of reflections | 1075 |
No. of parameters | 149 |
H-atom treatment | All H-atom parameters refined |
Δρmax, Δρmin (e Å−3) | 0.15, −0.14 |
Computer programs: COLLECT (Nonius, 1998), DENZO and SCALEPACK (Otwinowski & Minor, 1997), DENZO and SCALEPACK, SHELXS97 (Sheldrick, 1997), SHELXL97 (Sheldrick, 1997), SHELXTL-Plus (Sheldrick, 1991), SHELXL97 and PLATON (Spek, 2003).
D—H···A | D—H | H···A | D···A | D—H···A |
O3—H3O···O2i | 0.88 (2) | 2.32 (2) | 2.9881 (18) | 133.0 (17) |
O3—H3O···O3i | 0.88 (2) | 2.06 (2) | 2.8713 (8) | 153.1 (19) |
Symmetry code: (i) x−1/2, −y+3/2, −z+2. |
The title compound, (I), was synthesized to proof the relative configuration in the projected total synthesis of curvicollides A—C using a catalytic asymmetric Claisen rearrangement (Abraham, Körner et al., 2004; Abraham, Körner & Hiersemann, 2004) and a diastereoselective reduction with K-Selectride (Körner & Hiersemann, 2006). In order to verify the assumed relative configuration of methyl-4-(benzyloxymethyl)-2-hydroxy-3-methylhex-5-enoate (the preparation of this intermediate will be described elsewhere; Körner & Hiersemann, 2007), the δ-lactone, (I), was prepared. Fig. 1 shows that the relative configuration of C2, C3 and C4 is as expected. The configuration of the chiral C atoms in (I) (C2 S, C3 S and C4 R) were assigned based on the previously described stereochemical course of the catalytic asymmetric Claisen rearrangement (CAC) using the chiral Lewis acid [Cu{(S,S)-tert-Butyl-box}] (H2O)2(SbF6)2 (Evans et al., 1999). In the crystal the molecules are linked via a bifurcated O—H ··· O hydrogen bridge (Table 1) and a chain of molecules is formed along the a axis.