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rac-(2aS,2a1R,3aR,3a1S,5aS,6aR)-2a-Allyl-2,4-di­chloro-2a,2a1,3a1,5a,6,6a-hexa­hydro-3aH-3-oxadi­cyclo­penta­[cd,gh]penta­len-3a-ol

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aDepartment of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai - 400076, India
*Correspondence e-mail: srk@chem.iitb.ac.in

Edited by W. T. A. Harrison, University of Aberdeen, Scotland (Received 8 October 2021; accepted 26 November 2021; online 16 December 2021)

The title racemic triquinane, C14H14Cl2O2, is composed of four five-membered rings, one of which is a tetra­hydro­furan ring to which an allyl group on one side and a hydroxyl group on the other side are attached. The core of the triquinane unit has a cis–syn–cis configuration. In the crystal, the mol­ecules are linked by pairwise O—H⋯O hydrogen bonds, generating inversion dimers featuring R22(8) loops.

3D view (loading...)
[Scheme 3D1]
Chemical scheme
[Scheme 1]

Structure description

Compounds with three fused five-membered rings, known as triquinanes, have gained considerable importance because this core is found in several biologically active compounds (Qiu et al., 2018[Qiu, Y., Lan, W.-J., Li, H.-J. & Chen, L.-P. (2018). Molecules, 23, 2095-2128.]; Kotha et al., 2020[Kotha, S. & Tangella, Y. (2020). Synlett, 31, 1976-2012.]). Therefore, convenient methods to prepare and functionalize triquinanes and the study of their stereochemistry are useful exercises (Mehta & Rao, 1985[Mehta, G. & Rao, K. S. (1985). J. Org. Chem. 50, 5537-5543.]). Our group has prepared triquinanes from cage compounds in a simplified manner using microwave irradiation (Kotha et al., 2019[Kotha, S., Cheekatla, S. R., Meshram, M., Bandi, V. & Seema, V. (2019). Asia. J. Org. Chem. 8, 2097-2104.]). Thereafter, we attempted to functionalize the triquinanes and observed a transannular attack at the keto centre (O1—C1—O2) leading to the formation of the title compound, 1.

Compound 1 has three carbocyclic rings (C1/C2/C3/C4/C5, C4/C5/C6/C7/C8 and C6/C7/C9/C10/C11) and a tera­hydro­furan ring (O1/C1/C5/C6/C11). The allyl group is unsymmetrically substituted at C11 and the hy­droxy group is attached to C1 (Fig. 1[link]a). There are six stereogenic centres in 1: in the arbitrarily chosen asymmetric mol­ecule, the configurations are C1 R, C4 R, C5 S, C6 R, C7 S and C11 S but crystal symmetry generates a racemic mixture.

[Figure 1]
Figure 1
The mol­ecular structure of 1 (a) viewed from above and (b) viewed from the front. Displacement ellipsoids are drawn at the 50% probability level.

The triquinane ring system consists of a cis–syn–cis configuration, i.e., the hydrogen atoms at the ring junction are all above the plane and the first and the third rings are below the plane (Fig. 1[link]b). The chlorine atoms are attached to the unsaturated bonds C2—C3 and C9—C10 in anti-manner with respect to the H atoms of the ring junction. The middle cyclo­pentyl ring adopts an envelope conformation and the side rings are almost planar.

In the crystal, the mol­ecules are linked by O—H⋯O hydrogen bonds, generating inversion dimers featuring R22(8) loops (Table 1[link], Fig. 2[link]) but no intra­molecular hydrogen bonds are present.

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A D—H H⋯A DA D—H⋯A
O2—H2⋯O1i 0.84 2.06 2.893 (3) 173
Symmetry code: (i) [-x, -y+1, -z+1].
[Figure 2]
Figure 2
The crystal packing of 1, viewed along the b-axis direction. The hydrogen bonding is shown using dotted lines.

Synthesis and crystallization

The synthesis scheme is shown in Fig. 3[link]. Indium ingots (51 mg, 2.7 eq) were cut into small pieces and transferred to a two-neck round-bottomed flask. Tetra­hydro­furan (3 ml) was transferred to the flask under nitro­gen at room temperature. Allyl iodide (0.5 ml) was added to this solution via a syringe. After one h, the starting material 2 (40 mg) and tri­methyl­chloro­silane (3 drops) was added to the reaction mixture. On completion of the reaction (TLC monitoring) after 1 h, water was added to the reaction mixture. The aqueous layer was extracted with diethyl ether (Lee et al. 2001[Lee, P. H., Ahn, H., Lee, K., Sung, S. & Kim, S. (2001). Tetrahedron Lett. 42, 37-39.]). The compound was purified with column chromatography and silica gel (100–200 mesh) was used. Ethyl acetate:petroleum ether (8% of ethyl acetate in total in 100 ml of solution) was used an eluent. After that, the crystals suitable for X-ray crystallographic analysis were grown in air in a glass vial using ethyl acetate as solvent (Fig. 3[link]).

[Figure 3]
Figure 3
Synthesis scheme for 1.

Characterization: colourless crystalline solid; m.p. 120–122°C; 1H NMR (500 MHz, CDCl3): δ = 5.73–5.62 (m, 3H), 5.20–5.14 (m, 2H), 3.39–3.30 (m, 2H), 3.23–3.20 (m, 1H), 3.02–2.98 (m, 1H), 2.63 (dd, J = 13.8, 7.0 Hz, 1H), 2.55 (dd, J = 13.8, 7.0 Hz, 1H), 1.95–1.87 (m, 1H), 1.78 (d, J = 13.9 Hz, 1H) p.p.m.; 13C NMR (125 MHz, CDCl3): δ = 134.1, 133.2, 133.1, 133.0, 132.5, 119.1, 115.5, 97.7, 58.8, 54.8, 47.7, 46.4, 40.4, 35.2 p.p.m.; HRMS (ESI): m/z calculated for C14H14Cl2NaO2 [M + Na]+: 307.0262; found: 307.0263.

Refinement

Crystal data, data collection and structure refinement details are summarized in Table 2[link].

Table 2
Experimental details

Crystal data
Chemical formula C14H14Cl2O2
Mr 285.15
Crystal system, space group Triclinic, P[\overline{1}]
Temperature (K) 150
a, b, c (Å) 7.2687 (10), 8.3648 (11), 11.7460 (18)
α, β, γ (°) 80.448 (4), 83.441 (4), 65.285 (4)
V3) 638.96 (16)
Z 2
Radiation type Mo Kα
μ (mm−1) 0.50
Crystal size (mm) 0.32 × 0.29 × 0.09
 
Data collection
Diffractometer Bruker APEXII CCD
Absorption correction Multi-scan (SADABS; Bruker, 2016[Bruker (2016). APEX2, SAINT and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.])
Tmin, Tmax 0.655, 0.746
No. of measured, independent and observed [I > 2σ(I)] reflections 19764, 2241, 1662
Rint 0.106
(sin θ/λ)max−1) 0.594
 
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.048, 0.107, 1.09
No. of reflections 2241
No. of parameters 164
H-atom treatment H-atom parameters constrained
Δρmax, Δρmin (e Å−3) 0.27, −0.33
Computer programs: APEX2 and SAINT (Bruker, 2016[Bruker (2016). APEX2, SAINT and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.]), SHELXT (Sheldrick, 2015a[Sheldrick, G. M. (2015a). Acta Cryst. A71, 3-8.]), SHELXL (Sheldrick, 2015b[Sheldrick, G. M. (2015b). Acta Cryst. C71, 3-8.]) and OLEX2 (Dolomanov et al., 2009[Dolomanov, O. V., Bourhis, L. J., Gildea, R. J., Howard, J. A. K. & Puschmann, H. (2009). J. Appl. Cryst. 42, 339-341.]).

Structural data


Computing details top

Data collection: APEX2 (Bruker, 2016); cell refinement: SAINT (Bruker, 2016); data reduction: SAINT (Bruker, 2016); program(s) used to solve structure: ShelXT (Sheldrick, 2015a); program(s) used to refine structure: SHELXL (Sheldrick, 2015b); molecular graphics: OLEX2 (Dolomanov et al., 2009); software used to prepare material for publication: OLEX2 (Dolomanov et al., 2009).

rac-(2aS,2a1R,3aR,3a1S,5aS,6aR)-2a-Allyl-2,4-dichloro-2a,2a1,3a1,5a,6,6a-hexahydro-3aH-3-oxadicyclopenta[cd,gh]pentalen-3a-ol top
Crystal data top
C14H14Cl2O2Z = 2
Mr = 285.15F(000) = 296
Triclinic, P1Dx = 1.482 Mg m3
a = 7.2687 (10) ÅMo Kα radiation, λ = 0.71073 Å
b = 8.3648 (11) ÅCell parameters from 3239 reflections
c = 11.7460 (18) Åθ = 2.7–25.0°
α = 80.448 (4)°µ = 0.50 mm1
β = 83.441 (4)°T = 150 K
γ = 65.285 (4)°Plate, clear light colourless
V = 638.96 (16) Å30.32 × 0.29 × 0.09 mm
Data collection top
Bruker APEXII CCD
diffractometer
1662 reflections with I > 2σ(I)
φ and ω scansRint = 0.106
Absorption correction: multi-scan
(SADABS; Bruker, 2016)
θmax = 25.0°, θmin = 2.7°
Tmin = 0.655, Tmax = 0.746h = 88
19764 measured reflectionsk = 99
2241 independent reflectionsl = 1313
Refinement top
Refinement on F2Primary atom site location: dual
Least-squares matrix: fullHydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.048H-atom parameters constrained
wR(F2) = 0.107 w = 1/[σ2(Fo2) + (0.0235P)2 + 1.1376P]
where P = (Fo2 + 2Fc2)/3
S = 1.09(Δ/σ)max < 0.001
2241 reflectionsΔρmax = 0.27 e Å3
164 parametersΔρmin = 0.33 e Å3
0 restraints
Special details top

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

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
Cl10.06076 (13)0.17026 (12)0.42861 (8)0.0269 (3)
Cl20.06759 (13)0.53279 (13)0.15245 (8)0.0328 (3)
O10.1461 (3)0.5253 (3)0.37821 (19)0.0191 (5)
O20.2783 (3)0.3694 (3)0.55085 (19)0.0221 (6)
H20.1577080.3919490.5747980.033*
C10.2966 (5)0.3622 (4)0.4322 (3)0.0185 (8)
C110.2225 (5)0.5758 (4)0.2653 (3)0.0192 (8)
C30.4551 (5)0.0894 (4)0.3551 (3)0.0209 (8)
H30.4747280.0225120.3354190.025*
C100.1821 (5)0.4890 (4)0.1739 (3)0.0194 (8)
C60.4571 (5)0.4848 (4)0.2673 (3)0.0179 (7)
H60.5181990.5722670.2660370.021*
C20.2846 (5)0.1995 (4)0.4009 (3)0.0198 (8)
C90.3446 (5)0.3828 (4)0.1197 (3)0.0211 (8)
H90.3421440.3179630.0611410.025*
C40.6154 (5)0.1623 (4)0.3377 (3)0.0203 (8)
H40.7328820.0861300.3864980.024*
C70.5363 (5)0.3772 (4)0.1626 (3)0.0206 (8)
H70.6043110.4352330.1014810.025*
C80.6874 (5)0.1927 (5)0.2120 (3)0.0240 (8)
H8A0.6882150.1007470.1683890.029*
H8B0.8260680.1886960.2074300.029*
C50.5042 (5)0.3485 (4)0.3779 (3)0.0195 (8)
H50.5848930.3712530.4318300.023*
C130.1802 (5)0.8510 (5)0.1251 (3)0.0270 (9)
H130.1520100.8104520.0610140.032*
C120.1281 (5)0.7775 (4)0.2438 (3)0.0253 (8)
H12A0.0211490.8200220.2545000.030*
H12B0.1744760.8237850.3019240.030*
C140.2611 (6)0.9658 (5)0.1035 (4)0.0399 (11)
H14A0.2915141.0095200.1652850.048*
H14B0.2896661.0060950.0257670.048*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Cl10.0202 (5)0.0279 (5)0.0360 (6)0.0142 (4)0.0005 (4)0.0023 (4)
Cl20.0145 (5)0.0479 (6)0.0353 (6)0.0122 (4)0.0051 (4)0.0026 (5)
O10.0093 (12)0.0173 (12)0.0240 (14)0.0000 (10)0.0021 (10)0.0013 (10)
O20.0154 (13)0.0278 (14)0.0207 (14)0.0065 (11)0.0014 (10)0.0045 (11)
C10.0109 (17)0.0171 (18)0.023 (2)0.0020 (14)0.0003 (14)0.0012 (15)
C110.0128 (18)0.0183 (18)0.022 (2)0.0031 (15)0.0037 (14)0.0039 (15)
C30.0184 (19)0.0157 (18)0.027 (2)0.0049 (15)0.0040 (15)0.0026 (15)
C100.0112 (18)0.0185 (18)0.028 (2)0.0057 (15)0.0039 (15)0.0008 (15)
C60.0095 (17)0.0166 (18)0.026 (2)0.0038 (14)0.0024 (14)0.0049 (15)
C20.0189 (19)0.0156 (18)0.024 (2)0.0074 (16)0.0053 (15)0.0039 (15)
C90.023 (2)0.0166 (18)0.022 (2)0.0073 (16)0.0035 (16)0.0008 (15)
C40.0108 (18)0.0173 (18)0.026 (2)0.0015 (15)0.0040 (14)0.0026 (15)
C70.0134 (18)0.0202 (18)0.025 (2)0.0049 (15)0.0038 (14)0.0021 (15)
C80.0125 (18)0.024 (2)0.030 (2)0.0022 (16)0.0001 (15)0.0045 (16)
C50.0116 (17)0.0228 (19)0.025 (2)0.0075 (15)0.0002 (14)0.0042 (15)
C130.026 (2)0.0174 (19)0.032 (2)0.0030 (16)0.0035 (16)0.0018 (16)
C120.019 (2)0.0178 (19)0.031 (2)0.0016 (16)0.0050 (16)0.0032 (16)
C140.056 (3)0.043 (3)0.032 (2)0.033 (2)0.002 (2)0.0005 (19)
Geometric parameters (Å, º) top
Cl1—C21.731 (3)C3—C41.506 (5)
Cl2—C101.734 (3)C10—C91.315 (5)
O1—C11.444 (4)C6—C71.557 (5)
O1—C111.445 (4)C6—C51.545 (5)
O2—C11.394 (4)C9—C71.515 (5)
C1—C21.506 (5)C4—C81.526 (5)
C1—C51.536 (4)C4—C51.552 (5)
C11—C101.508 (5)C7—C81.534 (5)
C11—C61.550 (4)C13—C121.501 (5)
C11—C121.520 (5)C13—C141.300 (5)
C3—C21.316 (5)
C1—O1—C11110.0 (2)C5—C6—C11105.6 (3)
O1—C1—C2112.9 (3)C5—C6—C7106.9 (3)
O1—C1—C5107.0 (3)C1—C2—Cl1119.8 (2)
O2—C1—O1107.8 (3)C3—C2—Cl1126.3 (3)
O2—C1—C2113.5 (3)C3—C2—C1113.9 (3)
O2—C1—C5113.0 (3)C10—C9—C7111.3 (3)
C2—C1—C5102.5 (3)C3—C4—C8114.6 (3)
O1—C11—C10111.4 (3)C3—C4—C5103.4 (3)
O1—C11—C6106.4 (2)C8—C4—C5106.3 (3)
O1—C11—C12106.8 (3)C9—C7—C6103.2 (3)
C10—C11—C6101.7 (3)C9—C7—C8115.4 (3)
C10—C11—C12113.9 (3)C8—C7—C6105.4 (3)
C12—C11—C6116.5 (3)C4—C8—C7105.9 (3)
C2—C3—C4111.8 (3)C1—C5—C6105.2 (3)
C11—C10—Cl2118.3 (2)C1—C5—C4107.3 (3)
C9—C10—Cl2126.5 (3)C6—C5—C4106.6 (3)
C9—C10—C11115.1 (3)C14—C13—C12125.0 (4)
C11—C6—C7107.5 (3)C13—C12—C11113.3 (3)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O2—H2···O1i0.842.062.893 (3)173
Symmetry code: (i) x, y+1, z+1.
 

Acknowledgements

We thank Darshan S. Mhatre for his help in collecting the X-ray data and with the structure refinement.

Funding information

Funding for this research was provided by: Defence Research and Development Organisation, Aeronautics Research and Development Board (grant No. ARDB/01/104189/M/I to Prof. S Kotha); University Grants Commission (scholarship to Saima Ansari); Council of Scientific and Industrial Research, India (scholarship to Naveen Kumar Gupta).

References

First citationBruker (2016). APEX2, SAINT and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.  Google Scholar
First citationDolomanov, O. V., Bourhis, L. J., Gildea, R. J., Howard, J. A. K. & Puschmann, H. (2009). J. Appl. Cryst. 42, 339–341.  Web of Science CrossRef CAS IUCr Journals Google Scholar
First citationKotha, S., Cheekatla, S. R., Meshram, M., Bandi, V. & Seema, V. (2019). Asia. J. Org. Chem. 8, 2097–2104.  CSD CrossRef CAS Google Scholar
First citationKotha, S. & Tangella, Y. (2020). Synlett, 31, 1976–2012.  CrossRef CAS Google Scholar
First citationLee, P. H., Ahn, H., Lee, K., Sung, S. & Kim, S. (2001). Tetrahedron Lett. 42, 37–39.  CrossRef CAS Google Scholar
First citationMehta, G. & Rao, K. S. (1985). J. Org. Chem. 50, 5537–5543.  CrossRef CAS Google Scholar
First citationQiu, Y., Lan, W.-J., Li, H.-J. & Chen, L.-P. (2018). Molecules, 23, 2095–2128.  CrossRef Google Scholar
First citationSheldrick, G. M. (2015a). Acta Cryst. A71, 3–8.  Web of Science CrossRef IUCr Journals Google Scholar
First citationSheldrick, G. M. (2015b). Acta Cryst. C71, 3–8.  Web of Science CrossRef IUCr Journals Google Scholar

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