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ISSN: 2056-9890

(S)-6-Methyl--caprolactone

aBijvoet Center for Biomolecular Research, Crystal and Structural Chemistry, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
*Correspondence e-mail: m.siegler@uu.nl

(Received 8 February 2008; accepted 15 February 2008; online 20 February 2008)

The chiral title compound, C7H12O2, a lactone derivative, features a seven-membered ring that adopts a chair conformation. The crystal structure is stabilized by weak C—H⋯O inter­actions occurring in the (100) plane. The absolute configuration was assigned on the basis of the enantioselective synthesis.

Related literature

For related literature, see: van As et al. (2005[As, B. A. C. van, van Buijtenen, J., Broxterman, Q. B., Verzijl, G. K. M., Heise, A., Palmans, A. R. A. & Meijer, E. W. (2005). J. Am. Chem. Soc. 28, 9964-9965.]); van Buijtenen et al. (2006[Buijtenen, J. van, van As, B. A. C., Meuldijk, J., Palmans, A. R. A., Vekemans, J. A. J. M., Hulshof, L. A. & Meijer, E. W. (2006). Chem. Commun. 30, 3169-3171.]). For details of the synthesis, see: van As et al. (2007[As, B. A. C. van, Chan, D., Kivit, J. J., Palmans, A. R. A. & Meijer, E. W. (2007). Tetrahedron Asymmetry, 18, 787-790.]). For geometry, see: Cremer & Pople (1975[Cremer, D. & Pople, J. A. (1975). J. Am. Chem. Soc. 97, 1354-1358.]).

[Scheme 1]

Experimental

Crystal data
  • C7H12O2

  • Mr = 128.17

  • Monoclinic, P 21

  • a = 6.757 (2) Å

  • b = 7.577 (2) Å

  • c = 7.586 (2) Å

  • β = 110.949 (13)°

  • V = 362.71 (17) Å3

  • Z = 2

  • Mo Kα radiation

  • μ = 0.08 mm−1

  • T = 150 (2) K

  • 0.35 × 0.15 × 0.10 mm

Data collection
  • Nonius KappaCCD diffractometer

  • Absorption correction: none

  • 10010 measured reflections

  • 889 independent reflections

  • 862 reflections with I > 2σ(I)

  • Rint = 0.041

Refinement
  • R[F2 > 2σ(F2)] = 0.027

  • wR(F2) = 0.072

  • S = 1.10

  • 889 reflections

  • 83 parameters

  • 1 restraint

  • H-atom parameters constrained

  • Δρmax = 0.12 e Å−3

  • Δρmin = −0.16 e Å−3

Table 1
Short-contact C—H⋯O interactions (Å, °) found in the (100) plane

C—H⋯O C—H H⋯O C⋯O C—H⋯A
C2—H2A⋯O1i 0.99 2.67 3.573 (2) 152
C5—H5A⋯O1ii 0.99 2.64 3.616 (2) 166
C5—H5B⋯O1ii 0.99 2.63 3.601 (2) 168
C6—H6⋯O1i 1.00 2.54 3.466 (2) 154
Symmetry codes: (i) -x+2, y-1/2, -z; (ii) x, y, z+1.

Data collection: COLLECT (Nonius, 1998[Nonius (1998). COLLECT. Nonius BV, Delft, The Netherlands.]); cell refinement: DENZO (Otwinowski & Minor, 1997[Otwinowski, Z. & Minor, W. (1997). Methods in Enzymology, Vol. 276, Macromolecular Crystallography, Part A, edited by C. W. Carter Jr & R. M. Sweet, pp. 307-326. New York: Academic Press.]); data reduction: DENZO; program(s) used to solve structure: SHELXS86 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); molecular graphics: PLATON (Spek, 2003[Spek, A. L. (2003). J. Appl. Cryst. 36, 7-13.]); software used to prepare material for publication: PLATON and Mercury (Macrae et al., 2006[Macrae, C. F., Edgington, P. R., McCabe, P., Pidcock, E., Shields, G. P., Taylor, R., Towler, M. & van de Streek, J. (2006). J. Appl. Cryst. 39, 453-457.]).

Supporting information


Comment top

The enantiomers (R)- and (S)-6-methyl-ε-caprolactone (6-MeCL) have been recently used as monomer units for chiral oligomerization and chiral polymerization reactions (van As et al., 2005; van Buijtenen et al., 2006). A new two-step enantioselective synthesis of (R)- and (S)-6-MeCL from a racemic mixture of 6-MeCL has been described recently (van As et al., 2007). The present paper describes the crystal structure of (S)-6-MeCL, (I).

The structure of (I) (Fig. 1) was solved in the non-centrosymmetric space group P21 with Z' = 1. The stereochemistry at the chiral center, C6, was assigned S based on the enantioselective synthesis of (S)-6-MeCL, which was reported to yield an enantiomeric excess greater than 99% (van As et al., 2007).

The seven-membered ring (O2/C1—C6) adopts a chair conformation with puckering parameters: Q2 = 0.453 (2) Å, ϕ2 = 130.6 (2)°, Q3 = 0.653 (2) Å, ϕ3 = 102.6 (2)° and with a total puckering amplitude Q = 0.795 (2)Å (Cremer & Pople, 1975).

The crystal structure (I) is stabilized by weak C–H···O interactions (Table 1) with the four shortest contacts involving the O1 atom. These short contacts occur between molecules in the (1 0 0) plane, Fig. 2.

Related literature top

For related literature, see: van As et al. (2005); van Buijtenen et al. (2006). For details of the synthesis, see: van As et al. (2007). For geometry, see: Cremer & Pople (1975).

Experimental top

Details about the synthesis of (S)-6-methyl-ε-caprolactone have been given in a previous paper (van As et al., 2007).

Refinement top

In the absence of significant anomalous scattering effects, XXX Friedel pairs were merged prior to the refinement. The H atoms were found in difference Fourier maps and subsequently placed at calculated positions with C–H = 0.99–1.00 Å, and with Uiso(H) = 1.2 or 1.5 times Ueq(carrier C).

Computing details top

Data collection: COLLECT (Nonius, 1998); cell refinement: DENZO (Otwinowski & Minor, 1997); data reduction: DENZO (Otwinowski & Minor, 1997); program(s) used to solve structure: SHELXS86 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: PLATON (Spek, 2003); software used to prepare material for publication: PLATON (Spek, 2003) and Mercury (Macrae et al., 2006).

Figures top
[Figure 1] Fig. 1. Molecular structure of (I) showing atom labelling and displacement ellipsoids at the 50% probability level.
[Figure 2] Fig. 2. The packing of one layer found in the crystal structure of (I) viewed down the a* direction. Molecules are connected by short C–H···O contacts in the (1 0 0) plane. Only one set of short contacts (dashed lines) is shown for clarity. The symmetry codes are: (i) 2 - x, -1/2 + y, -z; (iii) 2 - x, 1/2 + y, -z; (iv) x, y, z - 1.
(S)-3-methyl-2-oxepanone top
Crystal data top
C7H12O2F(000) = 140
Mr = 128.17Dx = 1.174 Mg m3
Monoclinic, P21Mo Kα radiation, λ = 0.71073 Å
Hall symbol: P 2ybCell parameters from 7835 reflections
a = 6.757 (2) Åθ = 1.0–27.5°
b = 7.577 (2) ŵ = 0.08 mm1
c = 7.586 (2) ÅT = 150 K
β = 110.949 (13)°Prism, colourless
V = 362.71 (17) Å30.35 × 0.15 × 0.10 mm
Z = 2
Data collection top
Nonius KappaCCD
diffractometer
862 reflections with I > 2σ(I)
Radiation source: rotating anodeRint = 0.041
Graphite monochromatorθmax = 27.5°, θmin = 3.5°
ϕ and ω scansh = 88
10010 measured reflectionsk = 99
889 independent reflectionsl = 99
Refinement top
Refinement on F2Secondary atom site location: difference Fourier map
Least-squares matrix: fullHydrogen site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.027H-atom parameters constrained
wR(F2) = 0.072 w = 1/[σ2(Fo2) + (0.0431P)2 + 0.0282P]
where P = (Fo2 + 2Fc2)/3
S = 1.10(Δ/σ)max < 0.001
889 reflectionsΔρmax = 0.12 e Å3
83 parametersΔρmin = 0.16 e Å3
1 restraintAbsolute structure: known chirality of atom C6(S)
Primary atom site location: structure-invariant direct methods
Crystal data top
C7H12O2V = 362.71 (17) Å3
Mr = 128.17Z = 2
Monoclinic, P21Mo Kα radiation
a = 6.757 (2) ŵ = 0.08 mm1
b = 7.577 (2) ÅT = 150 K
c = 7.586 (2) Å0.35 × 0.15 × 0.10 mm
β = 110.949 (13)°
Data collection top
Nonius KappaCCD
diffractometer
862 reflections with I > 2σ(I)
10010 measured reflectionsRint = 0.041
889 independent reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0271 restraint
wR(F2) = 0.072H-atom parameters constrained
S = 1.10Δρmax = 0.12 e Å3
889 reflectionsΔρmin = 0.16 e Å3
83 parametersAbsolute structure: known chirality of atom C6(S)
Special details top

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 > 2σ(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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
O11.03545 (16)0.06828 (15)0.16671 (13)0.0355 (3)
O21.11573 (13)0.04935 (14)0.13758 (12)0.0288 (2)
C10.9754 (2)0.03155 (18)0.03896 (16)0.0258 (3)
C20.7534 (2)0.0285 (2)0.07029 (18)0.0301 (3)
H2A0.75940.14220.00420.036*
H2B0.67780.04910.20690.036*
C30.6274 (2)0.1054 (2)0.0003 (2)0.0356 (3)
H3A0.66030.22610.03110.043*
H3B0.47400.08490.06690.043*
C40.6759 (2)0.0938 (2)0.2120 (2)0.0365 (3)
H4A0.63890.02600.24210.044*
H4B0.58410.17870.24610.044*
C50.9066 (2)0.1315 (2)0.33415 (18)0.0303 (3)
H5A0.94230.25280.30710.036*
H5B0.92050.12740.46850.036*
C61.06592 (19)0.00512 (19)0.30521 (16)0.0267 (3)
H61.00980.11810.29380.032*
C71.2785 (2)0.0148 (3)0.46522 (19)0.0403 (4)
H7A1.33330.13560.47590.060*
H7B1.37830.06600.43960.060*
H7C1.26150.01900.58370.060*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
O10.0442 (5)0.0406 (6)0.0260 (5)0.0001 (5)0.0177 (4)0.0018 (4)
O20.0248 (4)0.0400 (6)0.0219 (4)0.0028 (4)0.0087 (3)0.0022 (4)
C10.0305 (6)0.0245 (6)0.0221 (6)0.0029 (5)0.0093 (5)0.0007 (5)
C20.0272 (6)0.0341 (7)0.0255 (6)0.0021 (5)0.0050 (5)0.0041 (6)
C30.0242 (6)0.0431 (9)0.0365 (7)0.0058 (6)0.0074 (5)0.0002 (7)
C40.0298 (6)0.0451 (9)0.0382 (7)0.0031 (6)0.0166 (5)0.0030 (7)
C50.0360 (7)0.0322 (7)0.0254 (6)0.0015 (6)0.0143 (5)0.0026 (5)
C60.0265 (6)0.0330 (7)0.0202 (6)0.0027 (5)0.0079 (5)0.0028 (5)
C70.0311 (6)0.0598 (11)0.0252 (6)0.0040 (7)0.0043 (5)0.0070 (7)
Geometric parameters (Å, º) top
O1—C11.2095 (16)C4—H4A0.9900
O2—C11.3428 (15)C4—H4B0.9900
O2—C61.4659 (14)C5—C61.5140 (19)
C1—C21.5028 (18)C5—H5A0.9900
C2—C31.539 (2)C5—H5B0.9900
C2—H2A0.9900C6—C71.5152 (18)
C2—H2B0.9900C6—H61.0000
C3—C41.523 (2)C7—H7A0.9800
C3—H3A0.9900C7—H7B0.9800
C3—H3B0.9900C7—H7C0.9800
C4—C51.5288 (19)
C1—O2—C6122.88 (10)C5—C4—H4B108.6
O1—C1—O2117.15 (12)H4A—C4—H4B107.6
O1—C1—C2123.02 (11)C6—C5—C4114.69 (12)
O2—C1—C2119.82 (11)C6—C5—H5A108.6
C1—C2—C3112.99 (12)C4—C5—H5A108.6
C1—C2—H2A109.0C6—C5—H5B108.6
C3—C2—H2A109.0C4—C5—H5B108.6
C1—C2—H2B109.0H5A—C5—H5B107.6
C3—C2—H2B109.0O2—C6—C5112.13 (11)
H2A—C2—H2B107.8O2—C6—C7103.76 (10)
C4—C3—C2113.05 (12)C5—C6—C7111.89 (12)
C4—C3—H3A109.0O2—C6—H6109.6
C2—C3—H3A109.0C5—C6—H6109.6
C4—C3—H3B109.0C7—C6—H6109.6
C2—C3—H3B109.0C6—C7—H7A109.5
H3A—C3—H3B107.8C6—C7—H7B109.5
C3—C4—C5114.64 (11)H7A—C7—H7B109.5
C3—C4—H4A108.6C6—C7—H7C109.5
C5—C4—H4A108.6H7A—C7—H7C109.5
C3—C4—H4B108.6H7B—C7—H7C109.5
C6—O2—C1—O1178.35 (12)C3—C4—C5—C661.49 (19)
C6—O2—C1—C22.78 (18)C1—O2—C6—C568.78 (16)
O1—C1—C2—C3112.90 (16)C1—O2—C6—C7170.29 (13)
O2—C1—C2—C365.90 (16)C4—C5—C6—O280.45 (14)
C1—C2—C3—C481.25 (16)C4—C5—C6—C7163.43 (12)
C2—C3—C4—C561.39 (19)

Experimental details

Crystal data
Chemical formulaC7H12O2
Mr128.17
Crystal system, space groupMonoclinic, P21
Temperature (K)150
a, b, c (Å)6.757 (2), 7.577 (2), 7.586 (2)
β (°) 110.949 (13)
V3)362.71 (17)
Z2
Radiation typeMo Kα
µ (mm1)0.08
Crystal size (mm)0.35 × 0.15 × 0.10
Data collection
DiffractometerNonius KappaCCD
diffractometer
Absorption correction
No. of measured, independent and
observed [I > 2σ(I)] reflections
10010, 889, 862
Rint0.041
(sin θ/λ)max1)0.650
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.027, 0.072, 1.10
No. of reflections889
No. of parameters83
No. of restraints1
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å3)0.12, 0.16
Absolute structureKnown chirality of atom C6(S)

Computer programs: COLLECT (Nonius, 1998), DENZO (Otwinowski & Minor, 1997), SHELXS86 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), PLATON (Spek, 2003) and Mercury (Macrae et al., 2006).

Short-contact C—H···O interactions (Å, °) found in the (100) plane top
C—H···OC—HH···OC···OC—H···A
C2—H2A···O1i0.992.673.573 (2)152
C5—H5A···O1ii0.992.643.616 (2)166
C5—H5B···O1ii0.992.633.601 (2)168
C6—H6···O1i1.002.543.466 (2)154
Symmetry codes: (i) -x+2, y-1/2, -z; (ii) x, y, z+1.
 

Footnotes

Current address: Shell Global Solutions International BV, Badhuisweg 3, 1031 CM Amsterdam, PO Box 38000, 1030 BN Amsterdam, The Netherlands.

Acknowledgements

We thank Ir Bart A. C. van As, Dr Anja R. A. Palmans and Professor E. W. Meijer for providing crystals of the title compound. This work was supported by the Council for Chemical Sciences of the Netherlands Organization for Scientific Research (CW-NWO).

References

First citationAs, B. A. C. van, Chan, D., Kivit, J. J., Palmans, A. R. A. & Meijer, E. W. (2007). Tetrahedron Asymmetry, 18, 787–790.  Google Scholar
First citationAs, B. A. C. van, van Buijtenen, J., Broxterman, Q. B., Verzijl, G. K. M., Heise, A., Palmans, A. R. A. & Meijer, E. W. (2005). J. Am. Chem. Soc. 28, 9964–9965.  Google Scholar
First citationBuijtenen, J. van, van As, B. A. C., Meuldijk, J., Palmans, A. R. A., Vekemans, J. A. J. M., Hulshof, L. A. & Meijer, E. W. (2006). Chem. Commun. 30, 3169–3171.  Web of Science CrossRef Google Scholar
First citationCremer, D. & Pople, J. A. (1975). J. Am. Chem. Soc. 97, 1354–1358.  CrossRef CAS Web of Science Google Scholar
First citationMacrae, C. F., Edgington, P. R., McCabe, P., Pidcock, E., Shields, G. P., Taylor, R., Towler, M. & van de Streek, J. (2006). J. Appl. Cryst. 39, 453–457.  Web of Science CrossRef CAS IUCr Journals Google Scholar
First citationNonius (1998). COLLECT. Nonius BV, Delft, The Netherlands.  Google Scholar
First citationOtwinowski, Z. & Minor, W. (1997). Methods in Enzymology, Vol. 276, Macromolecular Crystallography, Part A, edited by C. W. Carter Jr & R. M. Sweet, pp. 307–326. New York: Academic Press.  Google Scholar
First citationSheldrick, G. M. (2008). Acta Cryst. A64, 112–122.  Web of Science CrossRef CAS IUCr Journals Google Scholar
First citationSpek, A. L. (2003). J. Appl. Cryst. 36, 7–13.  Web of Science CrossRef CAS IUCr Journals Google Scholar

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