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The cyclo­propane ring of the title compound, C17H16O2, shows a high level of substituent-induced bond-length asymmetry. The carboxyl group adopts a conformation that prompts electron-density transfer from the ring towards the carbonyl π system.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270107050883/av3113sup1.cif
Contains datablocks global, I

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S0108270107050883/av3113Isup2.hkl
Contains datablock I

CCDC reference: 659975

Comment top

Cyclopropanes are interesting building blocks often used in modern organic synthesis (de Meijere et al., 2006). In particular, cyclopropanecarboxylate groups are found in a number of biologically active species. Their synthesis is mostly based on a classical homologues Wittig reaction (Tombo & Bellus, 1991; Donaldson, 2001). Recently, we proposed a novel method based on transformation of the substituted α-phosphono-γ-lactones into the corresponding ethyl cyclopropanecarboxylates by treatment with sodium ethoxide in boiling THF (Krawczyk et al., 2005, 2007). The title compound, (I), is a key product of this synthesis. Morever, cyclopropane is an obvious example of a simple chemical system characterized by a substantial ring strain energy. Its molecular orbitals are prone to interactions with the exocyclic π electrons (Cameron et al., 1990). Spectroscopic and chemical studies have shown that the cyclopropyl group is similar to a double bond in many respects (Lauher & Ibers, 1975; Jason & Ibers, 1977).

A view of (I) with the atom-numbering scheme is shown in Fig. 1. The endocyclic C—C bonds show a distinctive bond-length asymmetry. The shortest bond (C1—C2; Table 1) is located opposite the carboxyl and benzyl substituents, while the longest (C2—C3) is positioned in front of the unsubstituted endocyclic C1 atom. C1—C3 is a distal bond for the phenyl substituent. Substituent-induced bond-length asymmetry in cyclopropanes was studied in a very systematic way by Allen (1980). He demonstrated that interactions of the Walsh (1947, 1949) orbitals with a π system of the substituent are responsible for the bond-length differences. In particular, for the carboxylate group, the maximum overlap occurs if the torsion angle τ (Xn,m—C—CO) is 0 or 180° (Xn,m is the mid-point of the distal Cn—Cm bond). For the title compound, the value is -164.6 (2)° (the transgauche conformation) and indicates the high level of orbital interactions. For the phenyl substituent Allen suggests to calculate τ as an average of the two torsion angles XC1,C3—C2—C12—C13 and XC1,C3—C2—C12—C17; these angles should be normalized to the range -90, 90°. The value calculated for (I) [τ = 63.4 (4)°] indicates that the phenyl ring adopts a conformation intermediate between gauche and perpendicular. The vicinal C3—C4 and C2—C12 bond lengths are very close to the model values (1.476 and 1.502 Å) as specified by Allen for the carboxylate and phenyl substituents, respectively.

The transgauche conformation of the carboxylic acid substituent fragment prompts electronic interactions involving the bonding σ,π and antibonding σ*,π* orbitals. The most important interactions (Table 2 and Fig. 2) were computed by the Weinhold natural bond orbitals deletion procedure (Glendening et al., 1992) for the wavefunctions calculated with GAUSSIAN03 (Frisch et al., 2004) at the B3LYP/6–311++G(d,p) level of theory for the X-ray-determined coordinates.

In particular, the endocyclic C1—C3 and C2—C3 bonds participate in the electron density transfer towards the carbonyl group in the σπ* fashion (Graczyk & Mikołajczyk, 1994) (28.5 and 11.6 kJ mol-1, respectively), while the reverse back–donation is much weaker (1.8 and 6.6 kJ mol-1, respectively). In comparison to the above effect, interaction of the phenyl ring with the cyclopropane ring has a more complex character and involves significant mutual σπ* and σ*–π interactions (19.7 and 13.1 kJ mol-1, respectively).

In the crystal structure, molecules form centrosymmetric dimers connected by strong hydrogen bonds linking carboxylate groups of both monomers. In terms of graph-set terminology (Etter et al., 1990; Bernstein et al., 1995), this system can be described as R22(8).

Related literature top

For related literature, see: Allen (1980); Bernstein et al. (1995); Cameron et al. (1990); Donaldson (2001); Etter et al. (1990); Frisch et al. (2004); Glendening et al. (1992); Graczyk & Mikołajczyk (1994); Jason & Ibers (1977); Krawczyk et al. (2005, 2007); Lauher & Ibers (1975); Meijere et al. (2006); Tombo & Bellus (1991); Walsh (1947, 1949).

Experimental top

To a suspension of sodium hydride (6.0 mmol) and α-diethoxyphosphoryl-α-benzyl-γ-phenyl-γ-butyrolactone (6.0 mmol) in tetrahydrofuran (15 ml) was added dropwise under argon atmosphere at room temperature a solution of ethanol (0.40 ml) in tetrahydrofuran (15 ml). The reaction mixture was stirred for 0.5 h and then heated at reflux for 8 h. After cooling to room temperature, saturated NaCl solution (5 ml) was added, and tetrahydrofuran was evaporated under reduced pressure. The residue was extracted with dichloromethane (3 × 15 ml) and dried (Na2SO4). After evaporation, the crude product was purified by column chromatography and subsequently hydrolized to give (I). Good quality single crystals were selected from the reaction mixture (Krawczyk et al., 2007).

Refinement top

H atoms were located in a difference Fourier map. Those bonded to C atoms were refined as riding. The hydroxy atom H1 was refined without constraints.

Computing details top

Data collection: SMART (Bruker, 2003); cell refinement: SAINT-Plus (Bruker, 2003); data reduction: SAINT-Plus (Bruker, 2003); program(s) used to solve structure: SHELXTL (Bruker, 2003); program(s) used to refine structure: SHELXTL (Bruker, 2003); molecular graphics: SHELXTL (Bruker, 2003); software used to prepare material for publication: SHELXTL (Bruker, 2003) and publCIF (Westrip, 2007).

Figures top
[Figure 1] Fig. 1. The molecule of the title compound. Displacement elipsoids are drawn at the 50% probability level.
[Figure 2] Fig. 2. Natural bond orbitals, as in (I), involved in the electron density transfer from the vicinal (a) C1—C3 and (b) C2—C3 bonds to the carbonyl group C4O2, accompanied by the orbitals describing the major cyclopropyl–phenyl interactions (c).
rac-trans-(1R,2R)-1-Benzyl-2-phenylcyclopropanecarboxylic acid top
Crystal data top
C17H16O2Z = 2
Mr = 252.30F(000) = 268
Triclinic, P1Dx = 1.252 Mg m3
a = 5.9983 (2) ÅMo Kα radiation, λ = 0.71073 Å
b = 9.5439 (4) ÅCell parameters from 5353 reflections
c = 12.7293 (5) Åθ = 2.3–28.1°
α = 111.330 (1)°µ = 0.08 mm1
β = 92.188 (1)°T = 293 K
γ = 97.965 (1)°Prism, colourless
V = 669.15 (4) Å30.50 × 0.20 × 0.15 mm
Data collection top
Bruker SMART APEX
diffractometer
2348 independent reflections
Radiation source: fine-focus sealed tube2270 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.021
ω scansθmax = 25.0°, θmin = 1.7°
Absorption correction: multi-scan
(SHELXTL; Bruker, 2003)
h = 77
Tmin = 0.872, Tmax = 0.988k = 1111
9804 measured reflectionsl = 1515
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)] = 0.043Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.112H atoms treated by a mixture of independent and constrained refinement
S = 1.07 w = 1/[σ2(Fo2) + (0.051P)2 + 0.1541P]
where P = (Fo2 + 2Fc2)/3
2348 reflections(Δ/σ)max < 0.001
176 parametersΔρmax = 0.16 e Å3
0 restraintsΔρmin = 0.14 e Å3
Crystal data top
C17H16O2γ = 97.965 (1)°
Mr = 252.30V = 669.15 (4) Å3
Triclinic, P1Z = 2
a = 5.9983 (2) ÅMo Kα radiation
b = 9.5439 (4) ŵ = 0.08 mm1
c = 12.7293 (5) ÅT = 293 K
α = 111.330 (1)°0.50 × 0.20 × 0.15 mm
β = 92.188 (1)°
Data collection top
Bruker SMART APEX
diffractometer
2348 independent reflections
Absorption correction: multi-scan
(SHELXTL; Bruker, 2003)
2270 reflections with I > 2σ(I)
Tmin = 0.872, Tmax = 0.988Rint = 0.021
9804 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0430 restraints
wR(F2) = 0.112H atoms treated by a mixture of independent and constrained refinement
S = 1.07Δρmax = 0.16 e Å3
2348 reflectionsΔρmin = 0.14 e Å3
176 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
O10.7410 (2)0.89897 (14)0.01402 (10)0.0689 (4)
H10.819 (4)0.951 (3)0.036 (2)0.121 (8)*
O21.06628 (18)0.98230 (13)0.12336 (9)0.0604 (3)
C10.5162 (3)0.79975 (19)0.16732 (14)0.0584 (4)
H110.44600.80130.23510.070*
H120.42990.83360.11770.070*
C20.6461 (2)0.67518 (17)0.11376 (12)0.0511 (4)
H30.63930.64130.03100.061*
C30.7705 (2)0.83928 (16)0.17714 (11)0.0449 (3)
C40.8697 (2)0.91330 (16)0.10207 (12)0.0471 (3)
C50.9050 (2)0.87711 (16)0.28991 (12)0.0459 (3)
H510.84060.80710.32430.055*
H521.05880.86030.27610.055*
C60.9119 (2)1.03798 (16)0.37287 (11)0.0449 (3)
C70.7264 (3)1.08002 (18)0.43037 (13)0.0574 (4)
H710.59511.00880.41580.069*
C80.7314 (3)1.2252 (2)0.50892 (15)0.0690 (5)
H810.60391.25120.54600.083*
C90.9231 (4)1.3310 (2)0.53248 (15)0.0703 (5)
H910.92751.42870.58600.084*
C101.1086 (3)1.2917 (2)0.47644 (15)0.0694 (5)
H1011.23971.36330.49210.083*
C111.1032 (3)1.14665 (18)0.39682 (14)0.0573 (4)
H1111.23041.12200.35890.069*
C120.6673 (3)0.55238 (16)0.15805 (12)0.0500 (4)
C130.5043 (3)0.50666 (19)0.21760 (15)0.0634 (4)
H1310.37940.55600.23380.076*
C140.5247 (4)0.3881 (2)0.25345 (17)0.0789 (6)
H1410.41350.35890.29380.095*
C150.7056 (4)0.3136 (2)0.23042 (17)0.0783 (6)
H1510.71800.23390.25460.094*
C160.8681 (4)0.3572 (2)0.17148 (17)0.0766 (5)
H1610.99190.30670.15520.092*
C170.8500 (3)0.47578 (19)0.13597 (15)0.0649 (4)
H1710.96290.50480.09640.078*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
O10.0753 (8)0.0827 (8)0.0588 (7)0.0017 (6)0.0085 (6)0.0449 (7)
O20.0594 (7)0.0729 (7)0.0585 (7)0.0039 (6)0.0052 (5)0.0383 (6)
C10.0511 (9)0.0707 (10)0.0632 (10)0.0143 (7)0.0056 (7)0.0349 (8)
C20.0555 (9)0.0543 (8)0.0429 (8)0.0030 (7)0.0021 (6)0.0201 (7)
C30.0495 (8)0.0469 (8)0.0438 (7)0.0114 (6)0.0066 (6)0.0218 (6)
C40.0544 (9)0.0465 (8)0.0453 (8)0.0130 (6)0.0039 (6)0.0212 (6)
C50.0522 (8)0.0477 (8)0.0459 (8)0.0113 (6)0.0066 (6)0.0255 (6)
C60.0542 (8)0.0478 (8)0.0406 (7)0.0090 (6)0.0031 (6)0.0256 (6)
C70.0633 (10)0.0568 (9)0.0524 (9)0.0066 (7)0.0125 (7)0.0212 (7)
C80.0863 (12)0.0655 (11)0.0567 (10)0.0222 (9)0.0177 (9)0.0201 (8)
C90.1087 (15)0.0495 (9)0.0507 (9)0.0138 (9)0.0014 (9)0.0167 (7)
C100.0828 (12)0.0574 (10)0.0638 (10)0.0098 (9)0.0095 (9)0.0269 (9)
C110.0580 (9)0.0603 (9)0.0562 (9)0.0042 (7)0.0016 (7)0.0269 (8)
C120.0593 (9)0.0461 (8)0.0400 (7)0.0008 (6)0.0019 (6)0.0141 (6)
C130.0661 (10)0.0619 (10)0.0639 (10)0.0022 (8)0.0126 (8)0.0277 (8)
C140.0967 (14)0.0694 (12)0.0762 (12)0.0057 (11)0.0183 (11)0.0398 (10)
C150.1142 (16)0.0515 (10)0.0715 (12)0.0048 (10)0.0004 (11)0.0296 (9)
C160.0980 (14)0.0596 (11)0.0763 (12)0.0247 (10)0.0106 (10)0.0259 (9)
C170.0755 (11)0.0612 (10)0.0625 (10)0.0149 (8)0.0196 (8)0.0256 (8)
Geometric parameters (Å, º) top
C1—C21.481 (2)C8—C91.365 (3)
C1—C31.508 (2)C8—H810.9300
C2—C31.540 (2)C9—C101.367 (3)
C2—C121.491 (2)C9—H910.9300
C3—C41.4779 (19)C10—C111.382 (2)
O2—C41.2362 (17)C10—H1010.9300
C3—C51.5152 (19)C11—H1110.9300
O1—C41.2901 (17)C12—C131.378 (2)
O1—H11.02 (3)C12—C171.382 (2)
C1—H110.9700C13—C141.383 (3)
C1—H120.9700C13—H1310.9300
C2—H30.9800C14—C151.362 (3)
C5—C61.508 (2)C14—H1410.9300
C5—H510.9700C15—C161.363 (3)
C5—H520.9700C15—H1510.9300
C6—C111.378 (2)C16—C171.378 (2)
C6—C71.381 (2)C16—H1610.9300
C7—C81.378 (2)C17—H1710.9300
C7—H710.9300
C2—C1—C362.02 (10)C8—C7—H71119.3
C1—C2—C359.88 (10)C6—C7—H71119.3
C1—C3—C258.10 (10)C9—C8—C7120.21 (17)
C4—O1—H1112.8 (14)C9—C8—H81119.9
C2—C1—H11117.6C7—C8—H81119.9
C3—C1—H11117.6C8—C9—C10119.25 (17)
C2—C1—H12117.6C8—C9—H91120.4
C3—C1—H12117.6C10—C9—H91120.4
H11—C1—H12114.7C9—C10—C11120.65 (17)
C1—C2—C12122.77 (13)C9—C10—H101119.7
C12—C2—C3121.19 (12)C11—C10—H101119.7
C1—C2—H3114.1C6—C11—C10120.85 (16)
C12—C2—H3114.1C6—C11—H111119.6
C3—C2—H3114.1C10—C11—H111119.6
C4—C3—C1117.41 (12)C13—C12—C17117.62 (15)
C4—C3—C5116.29 (12)C13—C12—C2122.14 (15)
C1—C3—C5119.54 (12)C17—C12—C2120.19 (14)
C4—C3—C2113.93 (12)C12—C13—C14120.67 (18)
C5—C3—C2118.79 (11)C12—C13—H131119.7
O2—C4—O1123.11 (13)C14—C13—H131119.7
O2—C4—C3120.76 (12)C15—C14—C13120.83 (18)
O1—C4—C3116.12 (13)C15—C14—H141119.6
C6—C5—C3114.71 (11)C13—C14—H141119.6
C6—C5—H51108.6C14—C15—C16119.27 (17)
C3—C5—H51108.6C14—C15—H151120.4
C6—C5—H52108.6C16—C15—H151120.4
C3—C5—H52108.6C15—C16—C17120.34 (19)
H51—C5—H52107.6C15—C16—H161119.8
C11—C6—C7117.59 (14)C17—C16—H161119.8
C11—C6—C5121.85 (13)C16—C17—C12121.27 (17)
C7—C6—C5120.53 (13)C16—C17—H171119.4
C8—C7—C6121.44 (16)C12—C17—H171119.4
C1—C3—C4—O2161.92 (14)C3—C5—C6—C775.75 (17)
C2—C3—C4—O2132.99 (14)C11—C6—C7—C80.0 (2)
C1—C2—C12—C1327.5 (2)C5—C6—C7—C8178.11 (14)
C1—C2—C12—C17155.23 (15)C6—C7—C8—C90.7 (3)
C3—C1—C2—C12109.79 (15)C7—C8—C9—C100.7 (3)
C2—C1—C3—C4102.45 (14)C8—C9—C10—C110.0 (3)
C2—C1—C3—C5107.42 (14)C7—C6—C11—C100.6 (2)
C1—C2—C3—C4108.48 (14)C5—C6—C11—C10177.43 (13)
C12—C2—C3—C4139.17 (14)C9—C10—C11—C60.6 (2)
C1—C2—C3—C5108.69 (14)C3—C2—C12—C1399.54 (18)
C12—C2—C3—C53.7 (2)C3—C2—C12—C1783.17 (19)
C5—C3—C4—O210.82 (19)C17—C12—C13—C140.1 (2)
C1—C3—C4—O119.14 (19)C2—C12—C13—C14177.30 (16)
C5—C3—C4—O1170.24 (12)C12—C13—C14—C150.2 (3)
C2—C3—C4—O145.96 (17)C13—C14—C15—C160.1 (3)
C4—C3—C5—C669.96 (16)C14—C15—C16—C170.2 (3)
C1—C3—C5—C680.49 (16)C15—C16—C17—C120.5 (3)
C2—C3—C5—C6148.06 (13)C13—C12—C17—C160.4 (3)
C3—C5—C6—C11106.23 (16)C2—C12—C17—C16176.98 (16)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O1—H1···O2i1.02 (3)1.61 (3)2.629 (2)175 (2)
Symmetry code: (i) x+2, y+2, z.

Experimental details

Crystal data
Chemical formulaC17H16O2
Mr252.30
Crystal system, space groupTriclinic, P1
Temperature (K)293
a, b, c (Å)5.9983 (2), 9.5439 (4), 12.7293 (5)
α, β, γ (°)111.330 (1), 92.188 (1), 97.965 (1)
V3)669.15 (4)
Z2
Radiation typeMo Kα
µ (mm1)0.08
Crystal size (mm)0.50 × 0.20 × 0.15
Data collection
DiffractometerBruker SMART APEX
diffractometer
Absorption correctionMulti-scan
(SHELXTL; Bruker, 2003)
Tmin, Tmax0.872, 0.988
No. of measured, independent and
observed [I > 2σ(I)] reflections
9804, 2348, 2270
Rint0.021
(sin θ/λ)max1)0.595
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.043, 0.112, 1.07
No. of reflections2348
No. of parameters176
H-atom treatmentH atoms treated by a mixture of independent and constrained refinement
Δρmax, Δρmin (e Å3)0.16, 0.14

Computer programs: SMART (Bruker, 2003), SAINT-Plus (Bruker, 2003), SHELXTL (Bruker, 2003) and publCIF (Westrip, 2007).

Selected geometric parameters (Å, º) top
C1—C21.481 (2)C3—C41.4779 (19)
C1—C31.508 (2)O2—C41.2362 (17)
C2—C31.540 (2)C3—C51.5152 (19)
C2—C121.491 (2)
C2—C1—C362.02 (10)C1—C3—C258.10 (10)
C1—C2—C359.88 (10)
C1—C3—C4—O2161.92 (14)C1—C2—C12—C1327.5 (2)
C2—C3—C4—O2132.99 (14)C1—C2—C12—C17155.23 (15)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O1—H1···O2i1.02 (3)1.61 (3)2.629 (2)175 (2)
Symmetry code: (i) x+2, y+2, z.
Energy of the selected electronic interactions calculated with the natural bond orbital theory top
Type of InteractionStabilization energy (kJ mol-1)
σ(C1—C3)–π*(C4O2)28.5
π(C4O2)–σ*(C1—C3)1.8
σ(C2—C3)–π*(C4O2)11.6
π(C4O2)–σ*(C2—C3)6.6
σ(C1—C2)–π*(C12—C17)19,7
π(C12—C17)–σ*(C1—C2)13.1
 

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