rac-(1R,1aR,4S,6aS)-Ethyl 4-carb­oxy-1,1a,2,3,4,5,6,6a-octa­hydro­cyclo­propa[f]indene-1-carboxyl­ate

In the title compound, C₁₄H₁₈O₄, the central six-membered ring subtends inter­planar angles of 3.5 (1), 78.4 (1) and 78.73 (4)°, respectively, with the five-membered ring, the cyclo­propane ring and the ester side chain. The C-C bond distal to the carbonyl substituent is shortened compared to the other two bonds of the cyclo­propane moiety. The carboxylic acid groups form inversion-symmetric dimers by hydrogen bonding.

Key indicators

• Single-crystal X-ray study
• T = 133 K
• Mean [sigma](C-C) = 0.003 Å
• R factor = 0.045
• wR factor = 0.108
• Data-to-parameter ratio = 15.6

checkCIF/PLATON results

No syntax errors found



Alert level C
GOODF01_ALERT_2_C  The least squares goodness of fit parameter lies
            outside the range 0.80 <> 2.00
            Goodness of fit given =      0.780
PLAT125_ALERT_4_C No _symmetry_space_group_name_Hall Given .......          ?
PLAT480_ALERT_4_C Long H...A H-Bond Reported H8A    ..  O3      ..       2.62 Ang.
PLAT480_ALERT_4_C Long H...A H-Bond Reported H9B    ..  O3      ..       2.63 Ang.
PLAT720_ALERT_4_C Number of Unusual/Non-Standard Label(s) ........          2

   0 ALERT level A = In general: serious problem
   0 ALERT level B = Potentially serious problem
   5 ALERT level C = Check and explain
   0 ALERT level G = General alerts; check

   0 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   1 ALERT type 2 Indicator that the structure model may be wrong or deficient
   0 ALERT type 3 Indicator that the structure quality may be low
   4 ALERT type 4 Improvement, methodology, query or suggestion

---

Computing details

Data collection: SMART (Bruker, 1998); cell refinement: SAINT (Bruker, 1998); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 1990); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: XP (Siemens, 1994); software used to prepare material for publication: SHELXL97.

rac-(1R,1aR,4S,6aS)-Ethyl 4-carboxy-1,1a,2,3,4,5,6,6a-octahydrocyclopropa[f]indene-1-carboxylate

Crystal data

C14H18O4	F(000) = 536
Mr = 250.28	Dx = 1.298 Mg m^−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
a = 21.075 (2) Å	Cell parameters from 2297 reflections
b = 7.4723 (7) Å	θ = 2.9–27.9°
c = 8.2054 (7) Å	µ = 0.09 mm^−1
β = 97.524 (2)°	T = 133 K
V = 1281.1 (2) Å^3	Lath, colourless
Z = 4	0.45 × 0.14 × 0.10 mm

Data collection

Bruker SMART 1000 CCD diffractometer	1437 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.064
Graphite monochromator	θmax = 26.4°, θmin = 2.0°
Detector resolution: 8.192 pixels mm^-1	h = −26→21
ω scans	k = −9→9
7734 measured reflections	l = −10→7
2622 independent reflections

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.045	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.108	H atoms treated by a mixture of independent and constrained refinement
S = 0.78	w = 1/[σ^2(Fo^2) + (0.0573P)^2 + 0.0846P] where P = (Fo^2 + 2Fc^2)/3
2622 reflections	(Δ/σ)max = 0.015
168 parameters	Δρmax = 0.20 e Å^−3
0 restraints	Δρmin = −0.19 e Å^−3

Special details

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.

Least-squares planes (x,y,z in crystal coordinates) and deviations from them (* indicates atom used to define plane)

19.1395 (0.0172) x - 3.0658 (0.0133) y - 0.2983 (0.0154) z = 1.7298 (0.0127)

* 0.0000 (0.0000) C1 * 0.0000 (0.0000) C1A * 0.0000 (0.0000) C6A

Rms deviation of fitted atoms = 0.0000

1.6196 (0.0153) x + 3.6233 (0.0050) y - 7.1695 (0.0031) z = 0.1158 (0.0055)

Angle to previous plane (with approximate e.s.d.) = 78.36 (0.12)

* -0.0323 (0.0013) C1A * -0.0589 (0.0013) C6A * 0.0912 (0.0014) C2 * -0.0575 (0.0014) C2A * -0.0391 (0.0013) C5A * 0.0965 (0.0013) C6

Rms deviation of fitted atoms = 0.0671

2.5831 (0.0197) x + 3.3419 (0.0067) y - 7.3389 (0.0038) z = 0.1554 (0.0081)

Angle to previous plane (with approximate e.s.d.) = 3.50 (0.10)

* 0.0124 (0.0012) C2A * -0.0001 (0.0012) C5A * -0.0187 (0.0012) C3 * 0.0182 (0.0012) C4 * -0.0118 (0.0012) C5

Rms deviation of fitted atoms = 0.0140

6.4152 (0.0174) x + 5.2540 (0.0043) y + 4.9005 (0.0036) z = 6.5457 (0.0011)

Angle to central ring (with approximate e.s.d.) = 78.73 (0.04)

* -0.0216 (0.0009) C1 * 0.0153 (0.0016) C7 * -0.0007 (0.0009) O3 * 0.0296 (0.0013) O4 * -0.0176 (0.0016) C8 * -0.0051 (0.0012) C9

Rms deviation of fitted atoms = 0.0178

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 (Ų)

	x	y	z	Uiso*/Ueq
C1	0.18675 (9)	0.5536 (3)	0.4933 (2)	0.0271 (5)
H1	0.2200	0.4773	0.5578	0.032*
C1A	0.18284 (10)	0.5474 (3)	0.3063 (2)	0.0298 (5)
H1A	0.1390	0.5628	0.2446	0.036*
C2	0.22552 (10)	0.4162 (3)	0.2324 (2)	0.0332 (5)
H2A	0.2148	0.2933	0.2646	0.040*
H2B	0.2170	0.4241	0.1111	0.040*
C2A	0.29514 (10)	0.4494 (3)	0.2857 (2)	0.0266 (5)
C3	0.34595 (10)	0.3201 (3)	0.2489 (2)	0.0331 (6)
H3A	0.3424	0.2953	0.1295	0.040*
H3B	0.3425	0.2058	0.3082	0.040*
C4	0.40966 (10)	0.4158 (3)	0.3099 (2)	0.0315 (5)
H4	0.4352	0.3406	0.3955	0.038*
C5	0.39091 (10)	0.5956 (3)	0.3892 (3)	0.0347 (6)
H5A	0.4072	0.5990	0.5080	0.042*
H5B	0.4082	0.6996	0.3346	0.042*
C5A	0.31920 (10)	0.5955 (3)	0.3624 (2)	0.0247 (5)
C6	0.28079 (10)	0.7493 (3)	0.4125 (2)	0.0301 (5)
H6A	0.2875	0.8540	0.3428	0.036*
H6B	0.2964	0.7814	0.5278	0.036*
C6A	0.21013 (10)	0.7089 (3)	0.3978 (2)	0.0283 (5)
H6A1	0.1816	0.8165	0.3884	0.034*
C7	0.12534 (10)	0.5744 (3)	0.5589 (2)	0.0272 (5)
C8	0.05941 (9)	0.4692 (3)	0.7514 (2)	0.0285 (5)
H8A	0.0240	0.4363	0.6650	0.034*
H8B	0.0511	0.5906	0.7919	0.034*
C9	0.06422 (10)	0.3369 (3)	0.8895 (3)	0.0382 (6)
H9A	0.0747	0.2186	0.8487	0.046*
H9B	0.0232	0.3309	0.9335	0.046*
H9C	0.0979	0.3744	0.9765	0.046*
C10	0.44904 (10)	0.4555 (3)	0.1743 (3)	0.0282 (5)
O1	0.50977 (7)	0.4876 (2)	0.22630 (18)	0.0409 (4)
H01	0.5311 (14)	0.503 (3)	0.133 (4)	0.085 (9)*
O2	0.42693 (7)	0.46296 (19)	0.02919 (17)	0.0357 (4)
O3	0.08291 (7)	0.67565 (19)	0.50266 (17)	0.0359 (4)
O4	0.12066 (6)	0.46462 (17)	0.68568 (15)	0.0267 (4)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
C1	0.0264 (12)	0.0293 (12)	0.0256 (11)	0.0023 (10)	0.0041 (9)	0.0019 (9)
C1A	0.0276 (12)	0.0366 (13)	0.0250 (11)	−0.0019 (10)	0.0023 (9)	0.0001 (10)
C2	0.0354 (14)	0.0360 (13)	0.0291 (12)	−0.0066 (11)	0.0074 (10)	−0.0052 (10)
C2A	0.0328 (13)	0.0283 (12)	0.0204 (10)	−0.0032 (10)	0.0091 (9)	0.0030 (9)
C3	0.0380 (14)	0.0307 (13)	0.0333 (12)	−0.0037 (11)	0.0144 (10)	−0.0021 (10)
C4	0.0326 (13)	0.0342 (13)	0.0293 (12)	0.0005 (11)	0.0098 (10)	0.0024 (10)
C5	0.0313 (13)	0.0412 (14)	0.0328 (12)	−0.0067 (11)	0.0085 (10)	−0.0115 (10)
C5A	0.0290 (12)	0.0289 (12)	0.0175 (10)	−0.0033 (10)	0.0086 (9)	0.0023 (9)
C6	0.0358 (14)	0.0281 (12)	0.0272 (11)	−0.0048 (10)	0.0076 (9)	−0.0023 (9)
C6A	0.0296 (12)	0.0287 (12)	0.0270 (11)	0.0023 (10)	0.0046 (9)	0.0031 (9)
C7	0.0268 (12)	0.0264 (12)	0.0275 (12)	−0.0012 (10)	0.0002 (9)	−0.0020 (10)
C8	0.0225 (12)	0.0351 (12)	0.0291 (11)	−0.0003 (10)	0.0083 (9)	−0.0025 (10)
C9	0.0310 (13)	0.0472 (15)	0.0375 (13)	−0.0040 (11)	0.0091 (10)	0.0056 (11)
C10	0.0268 (12)	0.0256 (12)	0.0325 (13)	0.0023 (10)	0.0054 (10)	−0.0009 (10)
O1	0.0283 (9)	0.0643 (12)	0.0310 (9)	−0.0045 (8)	0.0071 (7)	0.0027 (8)
O2	0.0303 (9)	0.0484 (10)	0.0287 (9)	−0.0026 (7)	0.0051 (7)	0.0016 (7)
O3	0.0307 (9)	0.0414 (9)	0.0366 (9)	0.0074 (8)	0.0076 (7)	0.0080 (7)
O4	0.0240 (8)	0.0297 (8)	0.0272 (7)	0.0005 (6)	0.0065 (6)	0.0032 (6)

Geometric parameters (Å, º)

C1—C7	1.473 (3)	C10—O1	1.317 (3)
C1—C6A	1.518 (3)	C1—H1	1.0000
C1—C1A	1.526 (3)	C1A—H1A	1.0000
C1A—C6A	1.496 (3)	C2—H2A	0.9900
C1A—C2	1.510 (3)	C2—H2B	0.9900
C2—C2A	1.496 (3)	C3—H3A	0.9900
C2A—C5A	1.327 (3)	C3—H3B	0.9900
C2A—C3	1.502 (3)	C4—H4	1.0000
C3—C4	1.546 (3)	C5—H5A	0.9900
C4—C10	1.502 (3)	C5—H5B	0.9900
C4—C5	1.566 (3)	C6—H6A	0.9900
C5—C5A	1.499 (3)	C6—H6B	0.9900
C5A—C6	1.493 (3)	C6A—H6A1	1.0000
C6—C6A	1.509 (3)	C8—H8A	0.9900
C7—O3	1.215 (2)	C8—H8B	0.9900
C7—O4	1.339 (2)	C9—H9A	0.9800
C8—O4	1.463 (2)	C9—H9B	0.9800
C8—C9	1.497 (3)	C9—H9C	0.9800
C10—O2	1.222 (2)	O1—H01	0.94 (3)
C7—C1—C6A	117.91 (17)	C1A—C2—H2A	109.0
C7—C1—C1A	115.86 (17)	C2A—C2—H2B	109.0
C6A—C1—C1A	58.85 (12)	C1A—C2—H2B	109.0
C6A—C1A—C2	121.01 (18)	H2A—C2—H2B	107.8
C6A—C1A—C1	60.30 (13)	C2A—C3—H3A	110.9
C2—C1A—C1	117.82 (17)	C4—C3—H3A	110.9
C2A—C2—C1A	112.82 (17)	C2A—C3—H3B	110.9
C5A—C2A—C2	125.05 (19)	C4—C3—H3B	110.9
C5A—C2A—C3	112.74 (19)	H3A—C3—H3B	108.9
C2—C2A—C3	122.15 (18)	C10—C4—H4	109.4
C2A—C3—C4	104.42 (16)	C3—C4—H4	109.4
C10—C4—C3	113.10 (17)	C5—C4—H4	109.4
C10—C4—C5	109.43 (17)	C5A—C5—H5A	110.9
C3—C4—C5	106.01 (16)	C4—C5—H5A	110.9
C5A—C5—C4	104.08 (16)	C5A—C5—H5B	110.9
C2A—C5A—C6	125.17 (19)	C4—C5—H5B	110.9
C2A—C5A—C5	112.65 (18)	H5A—C5—H5B	109.0
C6—C5A—C5	122.13 (18)	C5A—C6—H6A	109.0
C5A—C6—C6A	112.91 (17)	C6A—C6—H6A	109.0
C1A—C6A—C6	120.79 (17)	C5A—C6—H6B	109.0
C1A—C6A—C1	60.85 (13)	C6A—C6—H6B	109.0
C6—C6A—C1	119.69 (17)	H6A—C6—H6B	107.8
O3—C7—O4	123.45 (18)	C1A—C6A—H6A1	115.0
O3—C7—C1	124.38 (18)	C6—C6A—H6A1	115.0
O4—C7—C1	112.15 (17)	C1—C6A—H6A1	115.0
O4—C8—C9	106.73 (16)	O4—C8—H8A	110.4
O2—C10—O1	122.55 (18)	C9—C8—H8A	110.4
O2—C10—C4	123.61 (19)	O4—C8—H8B	110.4
O1—C10—C4	113.81 (19)	C9—C8—H8B	110.4
C7—O4—C8	115.50 (15)	H8A—C8—H8B	108.6
C7—C1—H1	117.1	C8—C9—H9A	109.5
C6A—C1—H1	117.1	C8—C9—H9B	109.5
C1A—C1—H1	117.1	H9A—C9—H9B	109.5
C6A—C1A—H1A	115.5	C8—C9—H9C	109.5
C2—C1A—H1A	115.5	H9A—C9—H9C	109.5
C1—C1A—H1A	115.5	H9B—C9—H9C	109.5
C2A—C2—H2A	109.0	C10—O1—H01	107.9 (18)
C7—C1—C1A—C6A	108.3 (2)	C5—C5A—C6—C6A	−171.15 (16)
C7—C1—C1A—C2	−139.96 (19)	C2—C1A—C6A—C6	2.6 (3)
C6A—C1—C1A—C2	111.7 (2)	C1—C1A—C6A—C6	109.1 (2)
C6A—C1A—C2—C2A	9.8 (3)	C2—C1A—C6A—C1	−106.5 (2)
C1—C1A—C2—C2A	−60.5 (2)	C5A—C6—C6A—C1A	−13.0 (3)
C1A—C2—C2A—C5A	−12.5 (3)	C5A—C6—C6A—C1	58.8 (2)
C1A—C2—C2A—C3	170.51 (16)	C7—C1—C6A—C1A	−104.86 (19)
C5A—C2A—C3—C4	−2.8 (2)	C7—C1—C6A—C6	144.24 (18)
C2—C2A—C3—C4	174.50 (17)	C1A—C1—C6A—C6	−110.9 (2)
C2A—C3—C4—C10	−116.79 (18)	C6A—C1—C7—O3	24.5 (3)
C2A—C3—C4—C5	3.1 (2)	C1A—C1—C7—O3	−42.3 (3)
C10—C4—C5—C5A	119.80 (18)	C6A—C1—C7—O4	−157.31 (17)
C3—C4—C5—C5A	−2.5 (2)	C1A—C1—C7—O4	135.89 (17)
C2—C2A—C5A—C6	1.7 (3)	C3—C4—C10—O2	20.8 (3)
C3—C2A—C5A—C6	178.93 (17)	C5—C4—C10—O2	−97.1 (2)
C2—C2A—C5A—C5	−175.96 (18)	C3—C4—C10—O1	−161.26 (17)
C3—C2A—C5A—C5	1.3 (2)	C5—C4—C10—O1	80.8 (2)
C4—C5—C5A—C2A	0.8 (2)	O3—C7—O4—C8	1.8 (3)
C4—C5—C5A—C6	−176.91 (17)	C1—C7—O4—C8	−176.36 (15)
C2A—C5A—C6—C6A	11.4 (3)	C9—C8—O4—C7	179.50 (16)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O1—H01···O2^i	0.94 (3)	1.71 (3)	2.6540 (19)	177 (3)
C4—H4···O2^ii	1.00	2.54	3.348 (3)	138
C8—H8A···O3^iii	0.99	2.62	3.588 (3)	166
C8—H8B···O3^iv	0.99	2.49	3.358 (2)	147
C9—H9B···O3^v	0.98	2.63	3.545 (2)	155
C6A—H6A1···O4^vi	1.00	2.56	3.417 (2)	144

Symmetry codes: (i) −x+1, −y+1, −z; (ii) x, −y+1/2, z+1/2; (iii) −x, −y+1, −z+1; (iv) x, −y+3/2, z+1/2; (v) −x, y−1/2, −z+3/2; (vi) x, −y+3/2, z−1/2.