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

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ISSN: 2414-3146

12-Ethyl-6a,10a-di­hydro-5H-6-oxachrysene

aDepartment of Chemistry, University of Toronto, Toronto, Ontario, M5S 3H6, Canada, and bDepartment of Chemistry, University of Guelph, Guelph, Ontario, N1G 2W1, Canada
*Correspondence e-mail: alan.lough@utoronto.ca

Edited by W. T. A. Harrison, University of Aberdeen, Scotland (Received 26 February 2020; accepted 1 March 2020; online 5 March 2020)

In the title compound, C19H16O, the pyran ring is in a half-chair conformation. The essentially planar naphthalene ring system (r.m.s. deviation = 0.020 Å) forms a dihedral angle of 14.37 (5)° with the fused benzene ring. In the crystal, pairs of mol­ecules are connected into inversion dimers by weak C—H⋯O hydrogen bonds to generate R22(6) loops.

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

Structure description

In past years, our research group has investigated the effects of various C1-substituted oxabenzonorbornadienes (OBD) on controlling the regioselectivity of ring-opening reactions (Hill et al., 2019[Hill, J., Wicks, C., Pounder, A. & Tam, W. (2019). Tetrahedron Lett. 60, 150990.]; Hill & Tam, 2019[Hill, J. & Tam, W. (2019). J. Org. Chem. 84, 8309-8314.]; Edmunds et al., 2015[Edmunds, M., Menard, M. L. & Tam, W. (2015). Synth. Commun. 45, 468-476.]; Raheem et al., 2014[Raheem, M. A., Edmunds, M. & Tam, W. (2014). Can. J. Chem. 92, 888-895.]; Boutin et al., 2019[Boutin, R., Koh, S. & Tam, W. (2019). Curr. Org. Synth. 16, 460-484.]). To date, there have been very limited investigations into the C1-tethered intra­molecular ring-opening reactions of OBD and derivatives thereof (Loh et al., 2016[Loh, C. C. J., Schmid, M., Webster, R., Yen, A., Yazdi, S. K., Franke, P. T. & Lautens, M. (2016). Angew. Chem. Int. Ed. 55, 10074-10078.]; Wicks et al., 2019[Wicks, C., Koh, S., Pounder, A., Carlson, E. & Tam, W. (2019). Tetrahedron Lett. 60, 151228.]). Recently, our group looked into the palladium-catalysed intra­molecular aryl­ation of oxabenzonorbornadiene derivatives. Reaction of the C1-tethered unsymmetrical OBD I (see Fig. 3[link]) in the presence of Pd(PPh3)2Cl2, Zn powder, and Et3N in aceto­nitrile afforded the dehydrated II and hydrated III ring-opened products in an 87% and 3% yield respectively. Of the two potential regioisomers, the reaction was found to give solely the C2-cyclized regioisomer.

[Figure 3]
Figure 3
The reaction scheme.

The mol­ecular structure of the title compound is shown in Fig. 1[link]. The pyran ring (C1—C4/O1/C9) is in a half-chair conformation with atoms O1 and C1 displaced from the mean plane of the other four atoms by −0.260 (1) and 0.330 (1) Å, respectively. The essentially planar naphthalene ring system (C2/C3/C10–C17) forms a dihedral angle of 14.37 (5)° with the fused benzene ring (C4–C9). In the crystal, pairs of mol­ecules are connected into inversion dimers (Fig. 2[link]) by weak C—H⋯O hydrogen bonds (Table 1[link]) to generate [R_{2}^{2}](6) loops.

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A D—H H⋯A DA D—H⋯A
C1—H1A⋯O1i 0.99 2.49 3.3514 (14) 146
Symmetry code: (i) -x, -y+1, -z+1.
[Figure 1]
Figure 1
The mol­ecular structure of the title compound with displacement ellipsoids drawn at the 30% probability level.
[Figure 2]
Figure 2
Part of the crystal structure with weak hydrogen bonds shown as dashed lines.

Synthesis and crystallization

To a 2 dram vial was added the aryl iodide-tethered oxabenzonorbornadiene I (73.0 mg, 0.180 mmol) (see Fig. 3[link]). The vial was purged with argon for 5 minutes before being imported into an inert glove box. Inside the glove box, Pd(PPh3)2Cl2 (10.8 mg, 15.3 µmol, 8 mol%) and Zn powder (41.3 mg, 0.631 mmol) were added to the vial and dissolved in 1 ml of MeCN, followed by subsequent addition of Et3N (0.12 ml, 8 mol%). The vial was exported and stirred at 333 K for 20 h. The crude solution was purified by flash chromatography (EtOAc:hexa­nes, 15: 85) by loading directly onto the column to obtained ring-opened products II (23.5 mg, 0.0904 mmol, 87%) and III (1.5 mg, 5.34 µmol, 3%) as white solids. These were subsequently crystallized from DCM solution by slow evaporation of the solvent to afford product II as colourless crystals.

Refinement

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

Table 2
Experimental details

Crystal data
Chemical formula C19H16O
Mr 260.32
Crystal system, space group Orthorhombic, Pbca
Temperature (K) 150
a, b, c (Å) 9.4802 (3), 14.9824 (7), 18.6565 (7)
V3) 2649.90 (18)
Z 8
Radiation type Mo Kα
μ (mm−1) 0.08
Crystal size (mm) 0.34 × 0.28 × 0.20
 
Data collection
Diffractometer Bruker Kappa APEX DUO CCD
Absorption correction Multi-scan (SADABS; Krause et al., 2015[Krause, L., Herbst-Irmer, R., Sheldrick, G. M. & Stalke, D. (2015). J. Appl. Cryst. 48, 3-10.])
Tmin, Tmax 0.712, 0.746
No. of measured, independent and observed [I > 2σ(I)] reflections 12018, 3052, 2504
Rint 0.024
(sin θ/λ)max−1) 0.651
 
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.038, 0.101, 1.04
No. of reflections 3052
No. of parameters 182
H-atom treatment H-atom parameters constrained
Δρmax, Δρmin (e Å−3) 0.22, −0.20
Computer programs: APEX3 and SAINT (Bruker, 2018[Bruker (2018). APEX3 and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA.]), SHELXT2014/5 (Sheldrick, 2015a[Sheldrick, G. M. (2015a). Acta Cryst. A71, 3-8.]), SHELXL2018/3 (Sheldrick, 2015b[Sheldrick, G. M. (2015b). Acta Cryst. C71, 3-8.]), PLATON (Spek, 2020[Spek, A. L. (2020). Acta Cryst. E76, 1-11.]) and publCIF (Westrip, 2010[Westrip, S. P. (2010). J. Appl. Cryst. 43, 920-925.]).

Structural data


Computing details top

Data collection: APEX3 (Bruker, 2018); cell refinement: APEX3 (Bruker, 2018); data reduction: SAINT (Bruker, 2018); program(s) used to solve structure: SHELXT2014/5 (Sheldrick, 2015a); program(s) used to refine structure: SHELXL2018/3 (Sheldrick, 2015b); molecular graphics: PLATON (Spek, 2020); software used to prepare material for publication: publCIF (Westrip, 2010).

12-Ethyl-6a,10a-dihydro-5H-6-oxachrysene top
Crystal data top
C19H16ODx = 1.305 Mg m3
Mr = 260.32Mo Kα radiation, λ = 0.71073 Å
Orthorhombic, PbcaCell parameters from 4405 reflections
a = 9.4802 (3) Åθ = 2.7–27.5°
b = 14.9824 (7) ŵ = 0.08 mm1
c = 18.6565 (7) ÅT = 150 K
V = 2649.90 (18) Å3Block, colourless
Z = 80.34 × 0.28 × 0.20 mm
F(000) = 1104
Data collection top
Bruker Kappa APEX DUO CCD
diffractometer
2504 reflections with I > 2σ(I)
Radiation source: sealed tube with Bruker Triumph monochromatorRint = 0.024
φ and ω scansθmax = 27.6°, θmin = 2.2°
Absorption correction: multi-scan
(SADABS; Krause et al., 2015)
h = 127
Tmin = 0.712, Tmax = 0.746k = 1419
12018 measured reflectionsl = 2317
3052 independent reflections
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullHydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.038H-atom parameters constrained
wR(F2) = 0.101 w = 1/[σ2(Fo2) + (0.045P)2 + 0.903P]
where P = (Fo2 + 2Fc2)/3
S = 1.04(Δ/σ)max < 0.001
3052 reflectionsΔρmax = 0.22 e Å3
182 parametersΔρmin = 0.20 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
O10.14745 (9)0.56200 (6)0.52772 (5)0.0288 (2)
C10.19567 (12)0.47662 (8)0.50242 (7)0.0253 (3)
H1A0.1132590.4405130.4875500.030*
H1B0.2432430.4448160.5421610.030*
C20.29601 (11)0.48465 (7)0.44035 (6)0.0203 (2)
C30.38550 (11)0.55736 (7)0.43874 (6)0.0195 (2)
C40.37337 (12)0.62461 (7)0.49599 (6)0.0205 (2)
C50.47302 (12)0.69135 (8)0.50892 (6)0.0233 (2)
H5A0.5570210.6928060.4811720.028*
C60.45198 (13)0.75556 (8)0.56139 (7)0.0268 (3)
H6A0.5203980.8009260.5689530.032*
C70.33054 (14)0.75316 (9)0.60274 (7)0.0296 (3)
H7A0.3157390.7971040.6386750.036*
C80.23061 (13)0.68699 (9)0.59193 (7)0.0289 (3)
H8A0.1477700.6851530.6205470.035*
C90.25251 (12)0.62354 (8)0.53905 (6)0.0233 (3)
C100.30578 (12)0.41727 (7)0.38677 (6)0.0213 (2)
C110.21812 (13)0.34026 (8)0.38753 (7)0.0271 (3)
H11A0.1486830.3340680.4239060.033*
C120.23206 (14)0.27487 (8)0.33676 (7)0.0321 (3)
H12A0.1724610.2239240.3381170.038*
C130.33420 (15)0.28297 (8)0.28273 (7)0.0318 (3)
H13A0.3436720.2372170.2478010.038*
C140.42019 (14)0.35610 (8)0.27990 (6)0.0268 (3)
H14A0.4886700.3605200.2429010.032*
C150.40889 (12)0.42557 (7)0.33134 (6)0.0216 (2)
C160.49793 (12)0.50263 (8)0.32932 (6)0.0218 (2)
C170.48407 (12)0.56564 (7)0.38189 (6)0.0212 (2)
H17A0.5427580.6169930.3802850.025*
C180.60196 (13)0.51671 (8)0.26905 (7)0.0284 (3)
H18A0.6511540.4597370.2591800.034*
H18B0.6736580.5607710.2844350.034*
C190.53232 (16)0.54966 (9)0.20008 (7)0.0357 (3)
H19A0.6049870.5611890.1638880.054*
H19B0.4802780.6048470.2098550.054*
H19C0.4670170.5040570.1822660.054*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
O10.0198 (4)0.0327 (5)0.0339 (5)0.0022 (3)0.0041 (4)0.0043 (4)
C10.0218 (5)0.0262 (6)0.0279 (6)0.0031 (5)0.0016 (5)0.0020 (5)
C20.0166 (5)0.0218 (5)0.0224 (6)0.0010 (4)0.0030 (4)0.0044 (4)
C30.0172 (5)0.0201 (5)0.0213 (5)0.0022 (4)0.0026 (4)0.0034 (4)
C40.0199 (5)0.0209 (5)0.0206 (5)0.0027 (4)0.0034 (4)0.0038 (4)
C50.0231 (5)0.0223 (6)0.0245 (6)0.0005 (4)0.0022 (5)0.0043 (5)
C60.0307 (6)0.0223 (6)0.0273 (6)0.0001 (5)0.0077 (5)0.0019 (5)
C70.0367 (7)0.0272 (6)0.0250 (6)0.0068 (5)0.0047 (5)0.0033 (5)
C80.0270 (6)0.0341 (7)0.0255 (6)0.0051 (5)0.0018 (5)0.0013 (5)
C90.0214 (5)0.0246 (6)0.0240 (6)0.0008 (4)0.0031 (4)0.0025 (5)
C100.0207 (5)0.0207 (5)0.0224 (6)0.0001 (4)0.0054 (4)0.0042 (4)
C110.0283 (6)0.0260 (6)0.0270 (6)0.0049 (5)0.0048 (5)0.0042 (5)
C120.0392 (7)0.0244 (6)0.0325 (7)0.0081 (5)0.0100 (6)0.0036 (5)
C130.0452 (8)0.0230 (6)0.0270 (6)0.0013 (5)0.0084 (6)0.0017 (5)
C140.0329 (6)0.0249 (6)0.0227 (6)0.0046 (5)0.0023 (5)0.0022 (5)
C150.0228 (5)0.0210 (5)0.0209 (6)0.0039 (4)0.0045 (4)0.0037 (4)
C160.0190 (5)0.0230 (5)0.0235 (6)0.0030 (4)0.0012 (4)0.0048 (4)
C170.0182 (5)0.0195 (5)0.0260 (6)0.0008 (4)0.0011 (4)0.0035 (4)
C180.0259 (6)0.0275 (6)0.0317 (7)0.0020 (5)0.0072 (5)0.0001 (5)
C190.0441 (8)0.0337 (7)0.0292 (7)0.0033 (6)0.0094 (6)0.0065 (5)
Geometric parameters (Å, º) top
O1—C91.3736 (14)C10—C151.4284 (16)
O1—C11.4381 (15)C11—C121.3691 (18)
C1—C21.5034 (16)C11—H11A0.9500
C1—H1A0.9900C12—C131.403 (2)
C1—H1B0.9900C12—H12A0.9500
C2—C31.3810 (15)C13—C141.3666 (18)
C2—C101.4237 (16)C13—H13A0.9500
C3—C171.4189 (16)C14—C151.4198 (16)
C3—C41.4728 (16)C14—H14A0.9500
C4—C51.3967 (16)C15—C161.4307 (16)
C4—C91.3995 (16)C16—C171.3676 (16)
C5—C61.3869 (17)C16—C181.5105 (16)
C5—H5A0.9500C17—H17A0.9500
C6—C71.3864 (18)C18—C191.5281 (18)
C6—H6A0.9500C18—H18A0.9900
C7—C81.3860 (18)C18—H18B0.9900
C7—H7A0.9500C19—H19A0.9800
C8—C91.3857 (17)C19—H19B0.9800
C8—H8A0.9500C19—H19C0.9800
C10—C111.4221 (16)
C9—O1—C1114.65 (9)C12—C11—C10121.15 (12)
O1—C1—C2112.50 (9)C12—C11—H11A119.4
O1—C1—H1A109.1C10—C11—H11A119.4
C2—C1—H1A109.1C11—C12—C13120.12 (12)
O1—C1—H1B109.1C11—C12—H12A119.9
C2—C1—H1B109.1C13—C12—H12A119.9
H1A—C1—H1B107.8C14—C13—C12120.58 (12)
C3—C2—C10120.27 (10)C14—C13—H13A119.7
C3—C2—C1117.94 (10)C12—C13—H13A119.7
C10—C2—C1121.69 (10)C13—C14—C15121.11 (12)
C2—C3—C17119.33 (10)C13—C14—H14A119.4
C2—C3—C4118.42 (10)C15—C14—H14A119.4
C17—C3—C4122.25 (10)C14—C15—C10118.50 (11)
C5—C4—C9117.57 (11)C14—C15—C16121.96 (11)
C5—C4—C3124.21 (10)C10—C15—C16119.55 (10)
C9—C4—C3118.19 (10)C17—C16—C15118.77 (10)
C6—C5—C4121.42 (11)C17—C16—C18120.02 (10)
C6—C5—H5A119.3C15—C16—C18121.17 (10)
C4—C5—H5A119.3C16—C17—C3122.62 (10)
C7—C6—C5119.62 (11)C16—C17—H17A118.7
C7—C6—H6A120.2C3—C17—H17A118.7
C5—C6—H6A120.2C16—C18—C19112.94 (10)
C8—C7—C6120.35 (12)C16—C18—H18A109.0
C8—C7—H7A119.8C19—C18—H18A109.0
C6—C7—H7A119.8C16—C18—H18B109.0
C9—C8—C7119.46 (12)C19—C18—H18B109.0
C9—C8—H8A120.3H18A—C18—H18B107.8
C7—C8—H8A120.3C18—C19—H19A109.5
O1—C9—C8117.48 (11)C18—C19—H19B109.5
O1—C9—C4120.86 (11)H19A—C19—H19B109.5
C8—C9—C4121.57 (11)C18—C19—H19C109.5
C11—C10—C2122.03 (11)H19A—C19—H19C109.5
C11—C10—C15118.54 (11)H19B—C19—H19C109.5
C2—C10—C15119.41 (10)
C9—O1—C1—C248.75 (13)C1—C2—C10—C112.20 (17)
O1—C1—C2—C333.77 (14)C3—C2—C10—C150.03 (16)
O1—C1—C2—C10150.00 (10)C1—C2—C10—C15176.18 (10)
C10—C2—C3—C172.03 (16)C2—C10—C11—C12177.98 (11)
C1—C2—C3—C17178.33 (10)C15—C10—C11—C120.41 (17)
C10—C2—C3—C4178.90 (10)C10—C11—C12—C130.06 (19)
C1—C2—C3—C42.61 (15)C11—C12—C13—C140.33 (19)
C2—C3—C4—C5167.10 (11)C12—C13—C14—C150.10 (19)
C17—C3—C4—C513.87 (17)C13—C14—C15—C100.38 (17)
C2—C3—C4—C914.86 (15)C13—C14—C15—C16179.98 (11)
C17—C3—C4—C9164.17 (10)C11—C10—C15—C140.62 (15)
C9—C4—C5—C61.40 (17)C2—C10—C15—C14177.81 (10)
C3—C4—C5—C6176.66 (10)C11—C10—C15—C16179.77 (10)
C4—C5—C6—C70.86 (18)C2—C10—C15—C161.80 (15)
C5—C6—C7—C80.10 (18)C14—C15—C16—C17178.02 (11)
C6—C7—C8—C90.48 (19)C10—C15—C16—C171.57 (16)
C1—O1—C9—C8150.11 (11)C14—C15—C16—C184.26 (16)
C1—O1—C9—C433.24 (15)C10—C15—C16—C18176.14 (10)
C7—C8—C9—O1176.72 (11)C15—C16—C17—C30.47 (17)
C7—C8—C9—C40.09 (18)C18—C16—C17—C3178.21 (10)
C5—C4—C9—O1177.52 (10)C2—C3—C17—C162.31 (17)
C3—C4—C9—O10.65 (16)C4—C3—C17—C16178.67 (10)
C5—C4—C9—C81.01 (17)C17—C16—C18—C19100.43 (13)
C3—C4—C9—C8177.16 (10)C15—C16—C18—C1977.25 (14)
C3—C2—C10—C11178.35 (10)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
C1—H1A···O1i0.992.493.3514 (14)146
Symmetry code: (i) x, y+1, z+1.
 

Acknowledgements

The University of Toronto thanks NSERC Canada for funding.

References

First citationBoutin, R., Koh, S. & Tam, W. (2019). Curr. Org. Synth. 16, 460–484.  Web of Science CrossRef CAS PubMed Google Scholar
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First citationHill, J. & Tam, W. (2019). J. Org. Chem. 84, 8309–8314.  Web of Science CrossRef CAS PubMed Google Scholar
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First citationRaheem, M. A., Edmunds, M. & Tam, W. (2014). Can. J. Chem. 92, 888–895.  Web of Science CrossRef CAS Google Scholar
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First citationSheldrick, G. M. (2015b). Acta Cryst. C71, 3–8.  Web of Science CrossRef IUCr Journals Google Scholar
First citationSpek, A. L. (2020). Acta Cryst. E76, 1–11.  Web of Science CrossRef IUCr Journals Google Scholar
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First citationWicks, C., Koh, S., Pounder, A., Carlson, E. & Tam, W. (2019). Tetrahedron Lett. 60, 151228.  Web of Science CrossRef Google Scholar

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