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Photolysis of a 2-(2-iso­propyl-benzoyl)­benzoate ester derivative in an oxy­gen-free environment results in the liberation of the alcohol from the ester and formation of the title spiro­lactone, C20H20O2. The mol­ecule of the title compound adopts the syn configuration with respect to the benzene rings, with a dihedral angle of 87.19 (5)° between the benzo­cyclo­butene and isobenzo­furan­one ring planes. The cyclo­butene ring is nearly planar, giving rise to ring distortion, as manifested in the bond distances and angles.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S160053680402940X/lh6311sup1.cif
Contains datablocks 2, global

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S160053680402940X/lh63112sup2.hkl
Contains datablock 2

CCDC reference: 259602

Key indicators

  • Single-crystal X-ray study
  • T = 150 K
  • Mean [sigma](C-C) = 0.003 Å
  • R factor = 0.060
  • wR factor = 0.130
  • Data-to-parameter ratio = 17.6

checkCIF/PLATON results

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No errors found in this datablock

Computing details top

Data collection: SMART (Bruker, 2001); cell refinement: SMART; data reduction: SAINT (Bruker, 2001); program(s) used to solve structure: SHELXTL (Sheldrick, 2003); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL and DIAMOND (Brandenburg, 2001); software used to prepare material for publication: SHELXTL.

3'-Isopropyl-8',8'-dimethyl-2-benzofuran-1-spiro-7'-bicyclo[4.2.0]octa- 1'(6'),2',4'-trien-3-one top
Crystal data top
C20H20O2F(000) = 624
Mr = 292.36Dx = 1.223 Mg m3
Monoclinic, P21/cMelting point = 377–378 K
Hall symbol: -P 2ybcMo Kα radiation, λ = 0.71073 Å
a = 11.8742 (4) ÅCell parameters from 6130 reflections
b = 10.0738 (3) Åθ = 2.5–27.0°
c = 13.3550 (4) ŵ = 0.08 mm1
β = 96.375 (1)°T = 150 K
V = 1587.62 (9) Å3Block, colorless
Z = 40.24 × 0.20 × 0.17 mm
Data collection top
Bruker SMART6000 PLATFORM CCD area-detector
diffractometer
3496 independent reflections
Radiation source: sealed tube2920 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.034
ω scansθmax = 27.1°, θmin = 2.5°
Absorption correction: multi-scan
(SADABS; Sheldrick, 2001)
h = 1515
Tmin = 0.922, Tmax = 0.987k = 1212
11970 measured reflectionsl = 1417
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)] = 0.060Hydrogen site location: mixed
wR(F2) = 0.130H-atom parameters constrained
S = 1.12 w = 1/[σ2(Fo2) + (0.0291P)2 + 1.3492P]
where P = (Fo2 + 2Fc2)/3
3496 reflections(Δ/σ)max < 0.001
199 parametersΔρmax = 0.34 e Å3
0 restraintsΔρmin = 0.24 e Å3
Special details top

Experimental. Single crystals were obtained from pentane. A suitable crystal was mounted on the tip of a glass fiber with paratone-N.

The first 50 frames of data were recollected for a decay correction. The decay correction was applied simultaneously with the absorption correction in SADABS. No formal measure of the extent of decay is printed out by this program.

The final unit cell is obtained from the refinement of the XYZ weighted centroids of reflections above 20 σ(I).

Note that the absorption correction parameters Tmin and Tmax also reflect beam corrections, etc. As a result, the numerical values for Tmin and Tmax may differ from expected values based solely absorption effects and crystal size.

Spectroscopic details: IR (neat) 2961, 2869, 1760, 1466, 1230 cm-1.

1H NMR (250 MHz, CDCl3) δ 7.9 (d, 1H), 7.5 (m, 2H), 7.1 (m, 3H), 6.9 (d, 1H), 3.0 (septet, 1H), 1.29 (s, 6H), 1.26 (d, 6H) p.p.m..

13C NMR (60 MHz, CDCl3) δ 170.5, 152.5, 149.0, 138.3, 133.2, 129.1, 127.2, 126.4, 125.2, 124.0, 122.8, 118.2, 92.1, 55.9, 35.0, 24.1, 23.7 p.p.m..

GC—MS m/z (rel. intensity): 292 (M+, 5), 249 (50), 221 (100).

HRMS calcd. for C20H21O2 [M+H]+, 293.1542, found 293.1536.

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 out to 0.78 Å. 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
O10.31294 (11)0.48730 (13)0.13950 (10)0.0232 (3)
O20.15109 (12)0.57151 (14)0.06357 (10)0.0297 (3)
C20.20896 (15)0.47580 (19)0.08549 (13)0.0218 (4)
C30.18921 (15)0.33482 (19)0.06196 (13)0.0220 (4)
C40.09866 (16)0.2752 (2)0.00330 (15)0.0275 (4)
H40.03570.32560.02580.033*
C50.10453 (18)0.1399 (2)0.01060 (15)0.0321 (5)
H50.04440.09570.05010.038*
C60.19710 (18)0.0671 (2)0.03238 (15)0.0302 (5)
H60.19880.02610.02180.036*
C70.28713 (16)0.1274 (2)0.09035 (14)0.0251 (4)
H70.35040.07720.11880.030*
C80.28157 (15)0.26304 (19)0.10527 (13)0.0202 (4)
C90.36430 (15)0.35744 (18)0.16087 (13)0.0193 (4)
C100.48861 (15)0.34957 (18)0.14576 (13)0.0198 (4)
C110.56400 (16)0.35548 (19)0.07372 (14)0.0228 (4)
H110.53970.37090.00450.027*
C120.67733 (16)0.33744 (19)0.10931 (14)0.0238 (4)
H120.73200.34070.06250.029*
C130.71483 (15)0.31457 (18)0.21137 (14)0.0214 (4)
C140.63644 (15)0.30620 (18)0.28176 (13)0.0202 (4)
H140.65940.28840.35090.024*
C150.52366 (15)0.32507 (17)0.24594 (14)0.0194 (4)
C160.40471 (15)0.33613 (19)0.27923 (13)0.0207 (4)
C170.84104 (15)0.3022 (2)0.24444 (15)0.0253 (4)
H170.85100.28610.31880.030*
C180.89344 (18)0.1857 (2)0.1939 (2)0.0422 (6)
H18A0.85920.10270.21410.063*
H18B0.97530.18360.21440.063*
H18C0.87960.19560.12050.063*
C190.90337 (17)0.4303 (2)0.22424 (18)0.0332 (5)
H19A0.98310.42240.25160.050*
H19B0.86870.50480.25670.050*
H19C0.89830.44590.15150.050*
C200.39013 (17)0.4606 (2)0.34184 (15)0.0278 (4)
H20A0.31000.47160.35110.042*
H20B0.41630.53830.30680.042*
H20C0.43480.45170.40770.042*
C210.35664 (17)0.2144 (2)0.32678 (15)0.0282 (4)
H21A0.27460.22490.32700.042*
H21B0.39230.20450.39610.042*
H21C0.37200.13530.28780.042*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
O10.0214 (7)0.0205 (7)0.0265 (7)0.0024 (5)0.0019 (5)0.0027 (5)
O20.0275 (7)0.0306 (8)0.0306 (8)0.0115 (6)0.0019 (6)0.0050 (6)
C20.0193 (9)0.0280 (10)0.0185 (9)0.0039 (8)0.0041 (7)0.0045 (7)
C30.0186 (9)0.0280 (10)0.0198 (9)0.0017 (8)0.0040 (7)0.0022 (7)
C40.0176 (9)0.0403 (12)0.0242 (10)0.0003 (8)0.0000 (7)0.0045 (9)
C50.0266 (10)0.0421 (13)0.0271 (10)0.0120 (9)0.0007 (8)0.0042 (9)
C60.0347 (11)0.0262 (11)0.0302 (11)0.0057 (9)0.0061 (9)0.0014 (8)
C70.0249 (10)0.0251 (10)0.0252 (10)0.0018 (8)0.0021 (8)0.0019 (8)
C80.0175 (9)0.0259 (10)0.0175 (8)0.0007 (7)0.0035 (7)0.0035 (7)
C90.0179 (9)0.0195 (9)0.0201 (9)0.0011 (7)0.0003 (7)0.0033 (7)
C100.0185 (9)0.0177 (9)0.0220 (9)0.0009 (7)0.0029 (7)0.0014 (7)
C110.0241 (9)0.0251 (10)0.0188 (9)0.0025 (8)0.0008 (7)0.0014 (7)
C120.0212 (9)0.0241 (10)0.0272 (10)0.0020 (8)0.0073 (7)0.0001 (8)
C130.0188 (9)0.0162 (9)0.0285 (10)0.0000 (7)0.0002 (7)0.0002 (7)
C140.0218 (9)0.0176 (9)0.0204 (9)0.0005 (7)0.0011 (7)0.0007 (7)
C150.0215 (9)0.0152 (9)0.0217 (9)0.0008 (7)0.0035 (7)0.0008 (7)
C160.0172 (8)0.0244 (10)0.0201 (9)0.0018 (7)0.0005 (7)0.0029 (7)
C170.0168 (9)0.0264 (10)0.0317 (10)0.0001 (8)0.0008 (7)0.0031 (8)
C180.0231 (11)0.0300 (12)0.0727 (17)0.0050 (9)0.0026 (11)0.0037 (11)
C190.0223 (10)0.0320 (12)0.0444 (13)0.0052 (9)0.0001 (9)0.0004 (10)
C200.0257 (10)0.0326 (11)0.0250 (10)0.0059 (8)0.0030 (8)0.0014 (8)
C210.0255 (10)0.0341 (12)0.0247 (10)0.0019 (8)0.0012 (8)0.0091 (8)
Geometric parameters (Å, º) top
O1—C21.364 (2)C13—C141.397 (3)
O1—C91.458 (2)C13—C171.520 (2)
O2—C21.201 (2)C14—C151.384 (2)
C2—C31.468 (3)C14—H140.9500
C3—C81.385 (3)C15—C161.531 (2)
C3—C41.394 (3)C16—C211.521 (3)
C4—C51.379 (3)C16—C201.527 (3)
C4—H40.9500C17—C181.521 (3)
C5—C61.391 (3)C17—C191.526 (3)
C5—H50.9500C17—H171.0000
C6—C71.388 (3)C18—H18A0.9800
C6—H60.9500C18—H18B0.9800
C7—C81.383 (3)C18—H18C0.9800
C7—H70.9500C19—H19A0.9800
C8—C91.503 (3)C19—H19B0.9800
C9—C101.514 (2)C19—H19C0.9800
C9—C161.615 (2)C20—H20A0.9800
C10—C151.379 (3)C20—H20B0.9800
C10—C111.386 (3)C20—H20C0.9800
C11—C121.388 (3)C21—H21A0.9800
C11—H110.9500C21—H21B0.9800
C12—C131.405 (3)C21—H21C0.9800
C12—H120.9500
C2—O1—C9111.20 (14)C15—C14—H14121.6
O2—C2—O1121.36 (18)C13—C14—H14121.6
O2—C2—C3130.61 (18)C10—C15—C14122.43 (17)
O1—C2—C3108.01 (15)C10—C15—C1694.58 (15)
C8—C3—C4122.37 (19)C14—C15—C16142.93 (17)
C8—C3—C2108.38 (16)C21—C16—C20111.26 (16)
C4—C3—C2129.20 (18)C21—C16—C15117.61 (16)
C5—C4—C3117.01 (19)C20—C16—C15112.52 (15)
C5—C4—H4121.5C21—C16—C9115.56 (15)
C3—C4—H4121.5C20—C16—C9112.79 (15)
C4—C5—C6121.00 (19)C15—C16—C984.77 (13)
C4—C5—H5119.5C13—C17—C18111.91 (17)
C6—C5—H5119.5C13—C17—C19111.17 (16)
C7—C6—C5121.6 (2)C18—C17—C19110.09 (17)
C7—C6—H6119.2C13—C17—H17107.8
C5—C6—H6119.2C18—C17—H17107.8
C8—C7—C6117.80 (18)C19—C17—H17107.8
C8—C7—H7121.1C17—C18—H18A109.5
C6—C7—H7121.1C17—C18—H18B109.5
C7—C8—C3120.23 (17)H18A—C18—H18B109.5
C7—C8—C9131.08 (17)C17—C18—H18C109.5
C3—C8—C9108.65 (16)H18A—C18—H18C109.5
O1—C9—C8103.58 (14)H18B—C18—H18C109.5
O1—C9—C10114.44 (14)C17—C19—H19A109.5
C8—C9—C10119.64 (15)C17—C19—H19B109.5
O1—C9—C16112.54 (14)H19A—C19—H19B109.5
C8—C9—C16120.43 (15)C17—C19—H19C109.5
C10—C9—C1686.29 (13)H19A—C19—H19C109.5
C15—C10—C11122.18 (17)H19B—C19—H19C109.5
C15—C10—C994.23 (15)C16—C20—H20A109.5
C11—C10—C9143.57 (17)C16—C20—H20B109.5
C10—C11—C12115.65 (17)H20A—C20—H20B109.5
C10—C11—H11122.2C16—C20—H20C109.5
C12—C11—H11122.2H20A—C20—H20C109.5
C11—C12—C13122.97 (17)H20B—C20—H20C109.5
C11—C12—H12118.5C16—C21—H21A109.5
C13—C12—H12118.5C16—C21—H21B109.5
C14—C13—C12119.97 (17)H21A—C21—H21B109.5
C14—C13—C17120.58 (17)C16—C21—H21C109.5
C12—C13—C17119.43 (17)H21A—C21—H21C109.5
C15—C14—C13116.78 (16)H21B—C21—H21C109.5
C9—O1—C2—O2177.21 (16)C15—C10—C11—C121.1 (3)
C9—O1—C2—C33.88 (19)C9—C10—C11—C12178.9 (2)
O2—C2—C3—C8179.56 (19)C10—C11—C12—C130.0 (3)
O1—C2—C3—C81.7 (2)C11—C12—C13—C141.4 (3)
O2—C2—C3—C43.2 (3)C11—C12—C13—C17177.22 (18)
O1—C2—C3—C4175.60 (18)C12—C13—C14—C151.7 (3)
C8—C3—C4—C50.2 (3)C17—C13—C14—C15176.91 (17)
C2—C3—C4—C5176.74 (18)C11—C10—C15—C140.8 (3)
C3—C4—C5—C60.0 (3)C9—C10—C15—C14179.43 (17)
C4—C5—C6—C70.3 (3)C11—C10—C15—C16178.51 (18)
C5—C6—C7—C80.7 (3)C9—C10—C15—C162.81 (15)
C6—C7—C8—C30.9 (3)C13—C14—C15—C100.7 (3)
C6—C7—C8—C9178.31 (18)C13—C14—C15—C16175.6 (2)
C4—C3—C8—C70.6 (3)C10—C15—C16—C21118.81 (17)
C2—C3—C8—C7176.85 (16)C14—C15—C16—C2164.3 (3)
C4—C3—C8—C9178.60 (16)C10—C15—C16—C20109.90 (17)
C2—C3—C8—C91.11 (19)C14—C15—C16—C2067.0 (3)
C2—O1—C9—C84.40 (18)C10—C15—C16—C92.64 (14)
C2—O1—C9—C10136.35 (15)C14—C15—C16—C9179.5 (3)
C2—O1—C9—C16127.24 (15)O1—C9—C16—C21124.47 (17)
C7—C8—C9—O1174.41 (18)C8—C9—C16—C211.9 (2)
C3—C8—C9—O13.25 (18)C10—C9—C16—C21120.57 (17)
C7—C8—C9—C1045.6 (3)O1—C9—C16—C205.1 (2)
C3—C8—C9—C10132.08 (17)C8—C9—C16—C20127.69 (18)
C7—C8—C9—C1658.8 (3)C10—C9—C16—C20109.86 (16)
C3—C8—C9—C16123.56 (17)O1—C9—C16—C15117.36 (15)
O1—C9—C10—C15115.77 (16)C8—C9—C16—C15120.06 (17)
C8—C9—C10—C15120.51 (17)C10—C9—C16—C152.40 (13)
C16—C9—C10—C152.66 (14)C14—C13—C17—C18119.9 (2)
O1—C9—C10—C1166.1 (3)C12—C13—C17—C1861.4 (2)
C8—C9—C10—C1157.6 (3)C14—C13—C17—C19116.5 (2)
C16—C9—C10—C11179.2 (3)C12—C13—C17—C1962.1 (2)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
C4—H4···O2i0.952.453.375 (2)164
C12—H12···O2ii0.952.463.372 (2)160
Symmetry codes: (i) x, y+1, z; (ii) x+1, y+1, z.
 

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