organic compounds\(\def\hfill{\hskip 5em}\def\hfil{\hskip 3em}\def\eqno#1{\hfil {#1}}\)

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ISSN: 2056-9890

cis-3,3-Di­methyl-3,3a,4,5,6,6a-hexa­hydro-1H-cyclo­penta­[c]furan-1,6-dione

aChemistry Department, United States Naval Academy, 572M Holloway Road, Annapolis, Maryland 21402, USA
*Correspondence e-mail: wpearson@usna.edu

(Received 29 May 2008; accepted 6 June 2008; online 13 June 2008)

The bicyclic mol­ecule of the title compound, C9H12O3, contains two five-membered rings with different functional groups, viz. a ketone and an ester. Both rings assume an envelope conformation. The mean planes of these functional groups form a dihedral angle of 60.7 (1)°. The crystal structure exhibits weak inter­molecular C—H⋯O inter­actions, which link the mol­ecules into zigzag chains extended in the [010] direction. The unit cell contains a racemic mixture of enanti­omers.

Related literature

For related literature, see: Boeckman et al. (1989[Boeckman, R. K. Jr, Arvanitis, A. & Voss, M. E. (1989). J. Am. Chem. Soc. 111, 2737-2739.]); Wang et al. (2006[Wang, S.-K., Huang, M.-J. & Duh, C.-Y. (2006). J. Nat. Prod., 69, 1411-1416.]); Rodriguez (1998[Rodriguez, A. D. (1998). Tetrahedron, 54, 11683-11729.]); Corey & Kang (1984[Corey, E. J. & Kang, M. (1984). J. Am. Chem. Soc. 106, 5384-5385.]).

[Scheme 1]

Experimental

Crystal data
  • C9H12O3

  • Mr = 168.19

  • Triclinic, [P \overline 1]

  • a = 6.7333 (7) Å

  • b = 8.2897 (8) Å

  • c = 8.5906 (8) Å

  • α = 111.657 (2)°

  • β = 103.571 (2)°

  • γ = 92.809 (2)°

  • V = 428.30 (7) Å3

  • Z = 2

  • Mo Kα radiation

  • μ = 0.10 mm−1

  • T = 173 (2) K

  • 0.33 × 0.16 × 0.13 mm

Data collection
  • Bruker Kappa APEXII diffractometer

  • Absorption correction: multi-scan (SADABS; Bruker, 2007[Bruker (2007). APEX2 and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.]) Tmin = 0.934, Tmax = 0.988

  • 9157 measured reflections

  • 1961 independent reflections

  • 1632 reflections with I > 2σ(I)

  • Rint = 0.067

Refinement
  • R[F2 > 2σ(F2)] = 0.038

  • wR(F2) = 0.107

  • S = 1.06

  • 1961 reflections

  • 111 parameters

  • H-atom parameters constrained

  • Δρmax = 0.34 e Å−3

  • Δρmin = −0.16 e Å−3

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A D—H H⋯A DA D—H⋯A
C6—H6⋯O3i 1.00 2.51 3.3418 (13) 140
C4—H4B⋯O2ii 0.99 2.51 3.4821 (16) 166
Symmetry codes: (i) -x+2, -y, -z+1; (ii) -x+2, -y+1, -z+1.

Data collection: APEX2 (Bruker, 2007[Bruker (2007). APEX2 and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.]); cell refinement: APEX2; data reduction: APEX2; program(s) used to solve structure: SHELXTL (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL.

Supporting information


Comment top

Cyclopentane rings bearing multiple stereocenters are a common motif in terpenes, including ceroplastol (Boeckman et al., 1989) and dolabellanes. (Wang et al., 2006) Due to the wide variety of biological activities shown by these terpenes, interest in their synthesis is high. (Rodriguez, 1998) The bicyclic nature of the title compound makes it conformationally rigid. This rigidity is essential to its use as a stereochemical control element. Subsequent transformations require that one face of the molecule be more accessible than the other. For this reason, obtaining a crystal structure was an important goal.

The more accessible face of the molecule is oriented on the top side of figure 1. The angle between least-squares planes defined by the ketone and ester functional groups is 60.7 (1) degrees. Bond distances in this compound are quite reasonable when compared with expected values. The carbon-carbon bonds average 1.528 (10) Å in length. The two carbonyl bonds have an average length of 1.206 (2) Å while the ring oxygen, O1, is positioned 1.344 (1) Å from C1 and 1.488 (1) Å from C2. Strain in the ring system is observed in the bond angles on opposite sides of the molecule. Angles on the carbonyl side of the compound are considerably less than the expected 120 ° for an sp2 hybridized carbon. The angle defined by C4—C5—C6 is 107.93 (9) ° while the O1—C1—C6 angle is 110.06 (8) °. On the opposite side of the ring system, the C3—C7—C2 angle is more open at 117.00 (9) ° rather than the 109.5 ° that would expected around an sp3 hybridized, central atom.

Related literature top

For related literature, see: Boeckman et al. (1989); Wang et al. (2006); Rodriguez (1998); Corey & Kang (1984).

Experimental top

As part of a synthetic effort to prepare natural products, the title compound was prepared in a manner similar to that described by Corey & Kang (1984). Crystals were obtained by evaporation from ethanol.

Refinement top

Although all of the H atoms were located in difference Fourier maps, H-atoms were placed and then constrained to be at idealized positions. Methyl H atoms were positioned at 0.98 Å, methylene H atoms at 0.99 Å, and methyne H atoms at 1.00 Å from parent carbon atoms. A riding model was used during refinement. Methyl H atoms were allowed to rotate around the adjacent carbon-carbon bond with Uiso(H) = 1.5 times Ueq(C). Methylene H atoms were treated as idealized secondary H atoms with Uiso(H) = 1.2 times Ueq(C). Methyne H atoms were treated as idealized tertiary H atoms with Uiso(H) = 1.2 times Ueq(C).

Computing details top

Data collection: APEX2 (Bruker, 2007); cell refinement: APEX2 (Bruker, 2007); data reduction: APEX2 (Bruker, 2007); program(s) used to solve structure: SHELXTL (Sheldrick, 2008); program(s) used to refine structure: SHELXTL (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).

Figures top
[Figure 1] Fig. 1. The molecular structure of the title compound, with atom labels and 50% probability displacement ellipsoids for non-H atoms.
cis-3,3-Dimethyl-3,3a,4,5,6,6a-tetrahydro-1H- cyclopenta[c]furan-1,6-dione top
Crystal data top
C9H12O3Z = 2
Mr = 168.19F(000) = 180
Triclinic, P1Dx = 1.304 Mg m3
Dm = 1.258 Mg m3
Dm measured by flotation
Hall symbol: -P 1Melting point = 355–357 K
a = 6.7333 (7) ÅMo Kα radiation, λ = 0.71073 Å
b = 8.2897 (8) ÅCell parameters from 4358 reflections
c = 8.5906 (8) Åθ = 2.7–27.5°
α = 111.657 (2)°µ = 0.10 mm1
β = 103.571 (2)°T = 173 K
γ = 92.809 (2)°Regular parallelepiped, colourless
V = 428.30 (7) Å30.33 × 0.16 × 0.13 mm
Data collection top
Bruker KAPPA APEXII
diffractometer
1961 independent reflections
Radiation source: fine-focus sealed tube1632 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.067
Detector resolution: 512 pixels mm-1θmax = 27.5°, θmin = 2.7°
combination of ω and ϕ scansh = 88
Absorption correction: multi-scan
(SADABS; Bruker, 2007)
k = 1010
Tmin = 0.934, Tmax = 0.988l = 1111
9157 measured reflections
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.038Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.108H-atom parameters constrained
S = 1.06 w = 1/[σ2(Fo2) + (0.057P)2 + 0.0541P]
where P = (Fo2 + 2Fc2)/3
1961 reflections(Δ/σ)max < 0.001
111 parametersΔρmax = 0.34 e Å3
0 restraintsΔρmin = 0.16 e Å3
Crystal data top
C9H12O3γ = 92.809 (2)°
Mr = 168.19V = 428.30 (7) Å3
Triclinic, P1Z = 2
a = 6.7333 (7) ÅMo Kα radiation
b = 8.2897 (8) ŵ = 0.10 mm1
c = 8.5906 (8) ÅT = 173 K
α = 111.657 (2)°0.33 × 0.16 × 0.13 mm
β = 103.571 (2)°
Data collection top
Bruker KAPPA APEXII
diffractometer
1961 independent reflections
Absorption correction: multi-scan
(SADABS; Bruker, 2007)
1632 reflections with I > 2σ(I)
Tmin = 0.934, Tmax = 0.988Rint = 0.067
9157 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0380 restraints
wR(F2) = 0.108H-atom parameters constrained
S = 1.06Δρmax = 0.34 e Å3
1961 reflectionsΔρmin = 0.16 e Å3
111 parameters
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 > 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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
C11.03889 (16)0.18603 (13)0.76894 (14)0.0248 (3)
C20.75616 (16)0.19250 (14)0.88370 (14)0.0252 (3)
C30.67417 (18)0.39922 (14)0.71460 (15)0.0295 (3)
H3A0.53730.43520.72090.035*
H3B0.78140.48400.81640.035*
C40.7176 (2)0.38907 (16)0.54419 (17)0.0347 (3)
H4A0.58880.34890.44780.042*
H4B0.78110.50490.55630.042*
C50.86639 (18)0.25662 (15)0.51197 (15)0.0291 (3)
C60.84742 (15)0.14672 (13)0.61779 (13)0.0219 (2)
H60.81340.01850.54240.026*
C70.67906 (15)0.21095 (13)0.70880 (13)0.0218 (2)
H70.54260.13540.64030.026*
C80.70323 (19)0.32707 (17)1.03822 (15)0.0340 (3)
H8A0.77300.31221.14470.051*
H8B0.55340.31051.02130.051*
H8C0.74910.44551.04840.051*
C90.6960 (2)0.00625 (16)0.86661 (18)0.0367 (3)
H9A0.74180.07670.77150.055*
H9B0.54550.01910.84170.055*
H9C0.76190.00540.97570.055*
O10.98475 (11)0.22286 (11)0.91791 (10)0.0297 (2)
O20.98035 (16)0.23863 (12)0.41910 (13)0.0442 (3)
O31.21632 (12)0.18858 (11)0.76418 (12)0.0374 (2)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
C10.0204 (5)0.0238 (5)0.0290 (6)0.0052 (4)0.0081 (4)0.0081 (4)
C20.0191 (5)0.0320 (6)0.0262 (6)0.0068 (4)0.0083 (4)0.0115 (4)
C30.0307 (6)0.0276 (6)0.0334 (6)0.0132 (4)0.0132 (5)0.0117 (5)
C40.0396 (7)0.0349 (6)0.0399 (7)0.0161 (5)0.0172 (6)0.0211 (5)
C50.0317 (6)0.0280 (5)0.0307 (6)0.0071 (4)0.0131 (5)0.0121 (5)
C60.0199 (5)0.0204 (5)0.0250 (5)0.0046 (4)0.0088 (4)0.0067 (4)
C70.0174 (5)0.0238 (5)0.0228 (5)0.0043 (4)0.0066 (4)0.0065 (4)
C80.0314 (6)0.0449 (7)0.0243 (6)0.0107 (5)0.0112 (5)0.0091 (5)
C90.0382 (7)0.0392 (7)0.0457 (8)0.0112 (5)0.0213 (6)0.0246 (6)
O10.0198 (4)0.0411 (5)0.0271 (4)0.0078 (3)0.0051 (3)0.0124 (4)
O20.0564 (6)0.0452 (5)0.0526 (6)0.0199 (4)0.0381 (5)0.0274 (5)
O30.0182 (4)0.0444 (5)0.0440 (5)0.0058 (3)0.0102 (4)0.0097 (4)
Geometric parameters (Å, º) top
C1—O31.2043 (13)C4—H4B0.9900
C1—O11.3437 (13)C5—O21.2076 (14)
C1—C61.5216 (15)C5—C61.5255 (16)
C2—O11.4879 (12)C6—C71.5322 (13)
C2—C81.5171 (15)C6—H61.0000
C2—C91.5208 (16)C7—H71.0000
C2—C71.5367 (16)C8—H8A0.9800
C3—C41.5325 (17)C8—H8B0.9800
C3—C71.5452 (15)C8—H8C0.9800
C3—H3A0.9900C9—H9A0.9800
C3—H3B0.9900C9—H9B0.9800
C4—C51.5162 (16)C9—H9C0.9800
C4—H4A0.9900
O3—C1—O1122.38 (11)C1—C6—C7103.11 (8)
O3—C1—C6127.55 (11)C5—C6—C7106.73 (8)
O1—C1—C6110.06 (8)C1—C6—H6111.5
O1—C2—C8106.91 (9)C5—C6—H6111.5
O1—C2—C9107.27 (9)C7—C6—H6111.5
C8—C2—C9111.54 (10)C6—C7—C2103.16 (8)
O1—C2—C7102.78 (8)C6—C7—C3103.53 (8)
C8—C2—C7116.17 (9)C2—C7—C3117.00 (9)
C9—C2—C7111.33 (9)C6—C7—H7110.8
C4—C3—C7104.52 (9)C2—C7—H7110.8
C4—C3—H3A110.8C3—C7—H7110.8
C7—C3—H3A110.8C2—C8—H8A109.5
C4—C3—H3B110.8C2—C8—H8B109.5
C7—C3—H3B110.8H8A—C8—H8B109.5
H3A—C3—H3B108.9C2—C8—H8C109.5
C5—C4—C3104.25 (9)H8A—C8—H8C109.5
C5—C4—H4A110.9H8B—C8—H8C109.5
C3—C4—H4A110.9C2—C9—H9A109.5
C5—C4—H4B110.9C2—C9—H9B109.5
C3—C4—H4B110.9H9A—C9—H9B109.5
H4A—C4—H4B108.9C2—C9—H9C109.5
O2—C5—C4126.95 (11)H9A—C9—H9C109.5
O2—C5—C6125.12 (10)H9B—C9—H9C109.5
C4—C5—C6107.93 (9)C1—O1—C2110.98 (8)
C1—C6—C5112.00 (9)
C7—C3—C4—C534.23 (12)O1—C2—C7—C630.96 (9)
C3—C4—C5—O2160.31 (13)C8—C2—C7—C6147.30 (9)
C3—C4—C5—C619.95 (13)C9—C2—C7—C683.58 (10)
O3—C1—C6—C550.89 (15)O1—C2—C7—C381.93 (10)
O1—C1—C6—C5127.96 (9)C8—C2—C7—C334.42 (13)
O3—C1—C6—C7165.27 (11)C9—C2—C7—C3163.54 (9)
O1—C1—C6—C713.58 (11)C4—C3—C7—C635.35 (11)
O2—C5—C6—C170.16 (15)C4—C3—C7—C2148.02 (9)
C4—C5—C6—C1110.10 (10)O3—C1—O1—C2174.31 (10)
O2—C5—C6—C7177.71 (11)C6—C1—O1—C26.77 (11)
C4—C5—C6—C72.03 (12)C8—C2—O1—C1146.96 (10)
C1—C6—C7—C227.21 (10)C9—C2—O1—C193.29 (11)
C5—C6—C7—C2145.34 (9)C7—C2—O1—C124.16 (11)
C1—C6—C7—C395.19 (9)H6—C6—C7—H726.1
C5—C6—C7—C322.94 (11)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
C6—H6···O3i1.002.513.3418 (13)140
C4—H4B···O2ii0.992.513.4821 (16)166
Symmetry codes: (i) x+2, y, z+1; (ii) x+2, y+1, z+1.

Experimental details

Crystal data
Chemical formulaC9H12O3
Mr168.19
Crystal system, space groupTriclinic, P1
Temperature (K)173
a, b, c (Å)6.7333 (7), 8.2897 (8), 8.5906 (8)
α, β, γ (°)111.657 (2), 103.571 (2), 92.809 (2)
V3)428.30 (7)
Z2
Radiation typeMo Kα
µ (mm1)0.10
Crystal size (mm)0.33 × 0.16 × 0.13
Data collection
DiffractometerBruker KAPPA APEXII
diffractometer
Absorption correctionMulti-scan
(SADABS; Bruker, 2007)
Tmin, Tmax0.934, 0.988
No. of measured, independent and
observed [I > 2σ(I)] reflections
9157, 1961, 1632
Rint0.067
(sin θ/λ)max1)0.649
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.038, 0.108, 1.06
No. of reflections1961
No. of parameters111
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å3)0.34, 0.16

Computer programs: APEX2 (Bruker, 2007), SHELXTL (Sheldrick, 2008).

Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
C6—H6···O3i1.002.513.3418 (13)140.3
C4—H4B···O2ii0.992.513.4821 (16)165.8
Symmetry codes: (i) x+2, y, z+1; (ii) x+2, y+1, z+1.
 

Acknowledgements

The authors thank the Chemistry Department, United States Naval Academy, for supporting this work.

References

First citationBoeckman, R. K. Jr, Arvanitis, A. & Voss, M. E. (1989). J. Am. Chem. Soc. 111, 2737–2739.  CrossRef CAS Web of Science Google Scholar
First citationBruker (2007). APEX2 and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.  Google Scholar
First citationCorey, E. J. & Kang, M. (1984). J. Am. Chem. Soc. 106, 5384–5385.  CrossRef CAS Web of Science Google Scholar
First citationRodriguez, A. D. (1998). Tetrahedron, 54, 11683–11729.  CAS Google Scholar
First citationSheldrick, G. M. (2008). Acta Cryst. A64, 112–122.  Web of Science CrossRef CAS IUCr Journals Google Scholar
First citationWang, S.-K., Huang, M.-J. & Duh, C.-Y. (2006). J. Nat. Prod., 69, 1411–1416.  Web of Science CrossRef PubMed CAS Google Scholar

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