organic compounds
rac-Methyl (3aR*,4S*,5R*,7aR*)-5,7a-bis(acetyloxy)-3-oxo-2-phenyloctahydro-1H-isoindole-4-carboxylate
aDepartment of Chemistry, University of Douala, Faculty of Sciences, PO Box 24157, Douala, Republic of , Cameroon, bOrganic Chemistry Department, Peoples' Friendship University of Russia, Miklukho-Maklaya St. 6, Moscow, 117198, Russian Federation, and cX-Ray Structural Centre, A.N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, 28 Vavilov St, B-334, Moscow 119991, Russian Federation
*Correspondence e-mail: vkh@xray.ineos.ac.ru
The title molecule, C20H23NO7, the product of nucleophilic cleavage of the 3a,6-epoxy bridge in 1-oxo-2-phenyloctahydro-3a,6-epoxyisoindole-7-carboxylate, comprises a cis-fused bicyclic system containing a 2-pyrrolidinone ring in an (with the C atom bearing the carboxylate substituent as the flap) and a cyclohexane ring in a chair conformation. The carboxylate substituent occupies the equatorial position, whereas the two acetyloxy substituents are in axial positions. The N atom has a trigonal-planar geometry, the sum of the bond angles being 359.3 (3)°. The dihedral angle between the mean plane of the four planar atoms of the pyrrolidinone ring and the phenyl ring is 25.98 (6)°. In the crystal, molecules are linked into zigzag chains along the c-axis direction by C—H⋯O hydrogen bonds.
CCDC reference: 960159
Related literature
For the synthesis of 3a,6-epoxyisoindoles by intramolecular Diels–Alder reactions of furan, see: Vogel et al. (1999); Zubkov et al. (2005). For the synthesis of 2-phenyloctahydroisoindoles and their analogues, see: Balthaser et al. (2011); Zubkov et al. (2011). For related compounds, see: Zubkov et al. (2009, 2012); Claeys et al. (2010).
Experimental
Crystal data
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Data collection: APEX2 (Bruker, 2005); cell SAINT (Bruker, 2001); data reduction: SAINT; program(s) used to solve structure: SHELXTL (Sheldrick, 2008); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL.
Supporting information
CCDC reference: 960159
10.1107/S1600536813025129/aa2096sup1.cif
contains datablocks global, I. DOI:Structure factors: contains datablock I. DOI: 10.1107/S1600536813025129/aa2096Isup2.hkl
Supporting information file. DOI: 10.1107/S1600536813025129/aa2096Isup3.cml
BF3\ctdotEt2O (0.22 ml, 1.7 mmol) was added to a solution of the methyl 1-oxo-2-phenyloctahydro-3a,6-epoxyisoindole-7-carboxylate (0.2 g, 0.7 mmol) in acetic anhydride (5 ml) with stirring at room temperature during 24 h (monitoring by thin-layer chromatography). At the end of the reaction, the mixture was poured into water (50 ml), treated by aqueous sodium bicarbonate and extracted with chloroform (3 x 20 ml). The extract was dried over anhydrous magnesium sulfate. The residue was purified by crystallization from hexane – ethyl acetate to give product I (0.05 g, 0.13 mmol) as colourless solid. Yield 18%. The single-crystals of I were obtained by slow crystallization from a hexane – ethyl acetate mixture. M.p. = 418–419 K. IR (KBr), ν/cm-1: 1726, 1745 (NCO, CO2CH3, COCH3). 1H NMR (400 MHz, CDCl3, 293 K): δ = 7.54 (d, 2H, H2'(6'), J2'(6'),3'(5') = 7.6), 7.35 (t, 2H, H3'(5'), J2'(6'),3'(5') = J4',3'(5') = 7.6), 7.14 (t, 1H, H4', J3',4' = J4',5' = 7.6), 5.59 (br. s, 1H, H5), 4.21 (d, 1H, H1A, J1 A,1B = 10.2), 4.01 (d, 1H, H1B, J1 A,1B = 10.2), 3.75 (s, 3H, CO2Me), 3.59 (d, 1H, H3a, J3a,4 = 5.7), 2.91 (dd, 1H, H4, J4,5 = 1.9, J3a,4 = 5.7), 2.13 (s, 3H, COMe), 2.05 (s, 3H, COMe), 1.57–1.66, 1.89–2.03, 2.37–2.45, (m, 4H, H6, H7). 13C NMR (100 MHz, CDCl3, 293 K): δ = 170.5, 170.2, 170.0, 168.3 (C3, 2 x COCH3, CO2CH3), 138.9 (C1'), 129.0 (C3'(5')), 124.9 (C4'), 119.9 (C2'(6')), 79.0 (C7a), 65.5 (C5), 57.2 (C1), 52.0 (CO2Me), 48.3 (C3a), 40.9 (C4), 24.9, 23.9 (C6, C7), 21.2, 21.6 (2 x COMe). (EI—MS, 70 eV), m/z (Ir, (%)): 389 [M+] (33), 329 (100), 287 (28), 269 (22), 242 (26), 227 (16), 210 (68), 191 (33), 182 (33), 172 (16), 163 (16), 113 (15), 105 (52), 91 (67), 80 (47), 76 (83), 59 (43), 43 (52). Anal. Calcd. for C20H23NO7: C, 61.69; H, 5.95; N, 3.60. Found: C, 61.49; H, 6.04; N, 3.83.
The hydrogen atoms were placed in calculated positions with C—H = 0.95–1.00 Å and refined in the riding model with fixed isotropic displacement parameters [Uiso(H) = 1.5Ueq(C) for CH3-groups and Uiso(H) = 1.2Ueq(C) for the other groups].
Data collection: APEX2 (Bruker, 2005); cell
SAINT (Bruker, 2001); data reduction: SAINT (Bruker, 2001); program(s) used to solve structure: SHELXTL (Sheldrick, 2008); program(s) used to refine structure: SHELXTL (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).C20H23NO7 | F(000) = 1648 |
Mr = 389.39 | Dx = 1.345 Mg m−3 |
Monoclinic, C2/c | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -C 2yc | Cell parameters from 6890 reflections |
a = 12.3802 (7) Å | θ = 2.2–32.6° |
b = 18.3516 (10) Å | µ = 0.10 mm−1 |
c = 17.3596 (9) Å | T = 120 K |
β = 102.749 (1)° | Prism, colourless |
V = 3846.8 (4) Å3 | 0.24 × 0.20 × 0.18 mm |
Z = 8 |
Bruker APEXII CCD diffractometer | 5633 independent reflections |
Radiation source: fine-focus sealed tube | 4521 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.031 |
ϕ and ω scans | θmax = 30.0°, θmin = 2.0° |
Absorption correction: multi-scan (SADABS, Bruker, 2003) | h = −17→17 |
Tmin = 0.976, Tmax = 0.982 | k = −25→25 |
24538 measured reflections | l = −24→24 |
Refinement on F2 | Primary atom site location: structure-invariant direct methods |
Least-squares matrix: full | Secondary atom site location: difference Fourier map |
R[F2 > 2σ(F2)] = 0.041 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.108 | H-atom parameters constrained |
S = 1.04 | w = 1/[σ2(Fo2) + (0.0547P)2 + 1.6602P] where P = (Fo2 + 2Fc2)/3 |
5633 reflections | (Δ/σ)max = 0.001 |
256 parameters | Δρmax = 0.34 e Å−3 |
0 restraints | Δρmin = −0.27 e Å−3 |
C20H23NO7 | V = 3846.8 (4) Å3 |
Mr = 389.39 | Z = 8 |
Monoclinic, C2/c | Mo Kα radiation |
a = 12.3802 (7) Å | µ = 0.10 mm−1 |
b = 18.3516 (10) Å | T = 120 K |
c = 17.3596 (9) Å | 0.24 × 0.20 × 0.18 mm |
β = 102.749 (1)° |
Bruker APEXII CCD diffractometer | 5633 independent reflections |
Absorption correction: multi-scan (SADABS, Bruker, 2003) | 4521 reflections with I > 2σ(I) |
Tmin = 0.976, Tmax = 0.982 | Rint = 0.031 |
24538 measured reflections |
R[F2 > 2σ(F2)] = 0.041 | 0 restraints |
wR(F2) = 0.108 | H-atom parameters constrained |
S = 1.04 | Δρmax = 0.34 e Å−3 |
5633 reflections | Δρmin = −0.27 e Å−3 |
256 parameters |
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. |
x | y | z | Uiso*/Ueq | ||
O1 | 0.56464 (7) | 0.07894 (4) | 0.60114 (5) | 0.02273 (18) | |
O2 | 0.29290 (7) | 0.12128 (5) | 0.54848 (6) | 0.0303 (2) | |
O3 | 0.37833 (7) | 0.11721 (4) | 0.67737 (5) | 0.02327 (18) | |
O4 | 0.45957 (7) | 0.19171 (5) | 0.47486 (5) | 0.02225 (18) | |
O5 | 0.32731 (9) | 0.21367 (6) | 0.36585 (6) | 0.0436 (3) | |
O6 | 0.61038 (6) | 0.31985 (4) | 0.69818 (5) | 0.01906 (17) | |
O7 | 0.76385 (7) | 0.38200 (5) | 0.68767 (5) | 0.02475 (18) | |
C1 | 0.73913 (9) | 0.23138 (6) | 0.65747 (7) | 0.0180 (2) | |
H1A | 0.7920 | 0.2569 | 0.6316 | 0.022* | |
H1B | 0.7697 | 0.2299 | 0.7152 | 0.022* | |
N2 | 0.71434 (7) | 0.15773 (5) | 0.62498 (6) | 0.01699 (18) | |
C3 | 0.60532 (9) | 0.13840 (6) | 0.61919 (6) | 0.0167 (2) | |
C3A | 0.54746 (8) | 0.20432 (5) | 0.64506 (6) | 0.01519 (19) | |
H3A | 0.5493 | 0.1979 | 0.7025 | 0.018* | |
C4 | 0.42576 (9) | 0.21450 (6) | 0.60303 (6) | 0.0169 (2) | |
H4 | 0.3945 | 0.2518 | 0.6340 | 0.020* | |
C5 | 0.41288 (9) | 0.24521 (6) | 0.52002 (6) | 0.0200 (2) | |
H5 | 0.3329 | 0.2536 | 0.4954 | 0.024* | |
C6 | 0.47768 (10) | 0.31571 (6) | 0.52277 (7) | 0.0230 (2) | |
H6A | 0.4495 | 0.3516 | 0.5562 | 0.028* | |
H6B | 0.4667 | 0.3362 | 0.4688 | 0.028* | |
C7 | 0.60063 (10) | 0.30302 (6) | 0.55594 (7) | 0.0207 (2) | |
H7A | 0.6400 | 0.3503 | 0.5590 | 0.025* | |
H7B | 0.6300 | 0.2712 | 0.5193 | 0.025* | |
C7A | 0.62497 (9) | 0.26789 (5) | 0.63798 (6) | 0.0160 (2) | |
C8 | 0.79927 (9) | 0.11026 (6) | 0.61369 (6) | 0.0165 (2) | |
C9 | 0.90772 (9) | 0.12300 (6) | 0.65522 (7) | 0.0196 (2) | |
H9 | 0.9234 | 0.1630 | 0.6906 | 0.023* | |
C10 | 0.99269 (10) | 0.07721 (6) | 0.64477 (7) | 0.0220 (2) | |
H10 | 1.0662 | 0.0858 | 0.6735 | 0.026* | |
C11 | 0.97091 (10) | 0.01913 (6) | 0.59273 (7) | 0.0220 (2) | |
H11 | 1.0291 | −0.0122 | 0.5859 | 0.026* | |
C12 | 0.86307 (10) | 0.00707 (6) | 0.55054 (7) | 0.0214 (2) | |
H12 | 0.8481 | −0.0324 | 0.5144 | 0.026* | |
C13 | 0.77700 (9) | 0.05211 (6) | 0.56061 (6) | 0.0190 (2) | |
H13 | 0.7036 | 0.0434 | 0.5316 | 0.023* | |
C14 | 0.35836 (9) | 0.14570 (6) | 0.60423 (7) | 0.0205 (2) | |
C15 | 0.33283 (11) | 0.04564 (7) | 0.68386 (9) | 0.0309 (3) | |
H15A | 0.3523 | 0.0296 | 0.7391 | 0.046* | |
H15B | 0.3633 | 0.0113 | 0.6510 | 0.046* | |
H15C | 0.2521 | 0.0474 | 0.6659 | 0.046* | |
C16 | 0.40743 (10) | 0.17976 (7) | 0.39944 (7) | 0.0265 (3) | |
C17 | 0.46300 (12) | 0.11914 (8) | 0.36509 (8) | 0.0348 (3) | |
H17A | 0.4301 | 0.1148 | 0.3085 | 0.052* | |
H17B | 0.4531 | 0.0733 | 0.3917 | 0.052* | |
H17C | 0.5422 | 0.1297 | 0.3726 | 0.052* | |
C18 | 0.68623 (10) | 0.37373 (6) | 0.71805 (7) | 0.0199 (2) | |
C19 | 0.65958 (11) | 0.42028 (7) | 0.78205 (8) | 0.0273 (3) | |
H19A | 0.7274 | 0.4436 | 0.8115 | 0.041* | |
H19B | 0.6279 | 0.3899 | 0.8180 | 0.041* | |
H19C | 0.6059 | 0.4578 | 0.7586 | 0.041* |
U11 | U22 | U33 | U12 | U13 | U23 | |
O1 | 0.0219 (4) | 0.0148 (4) | 0.0313 (4) | −0.0026 (3) | 0.0054 (3) | −0.0028 (3) |
O2 | 0.0248 (4) | 0.0285 (5) | 0.0336 (5) | −0.0059 (4) | −0.0025 (4) | −0.0037 (4) |
O3 | 0.0257 (4) | 0.0189 (4) | 0.0263 (4) | −0.0069 (3) | 0.0080 (3) | −0.0004 (3) |
O4 | 0.0203 (4) | 0.0270 (4) | 0.0184 (4) | 0.0050 (3) | 0.0018 (3) | −0.0028 (3) |
O5 | 0.0446 (6) | 0.0527 (7) | 0.0259 (5) | 0.0213 (5) | −0.0089 (4) | −0.0071 (4) |
O6 | 0.0214 (4) | 0.0154 (4) | 0.0221 (4) | −0.0019 (3) | 0.0086 (3) | −0.0049 (3) |
O7 | 0.0274 (4) | 0.0197 (4) | 0.0288 (4) | −0.0068 (3) | 0.0099 (4) | −0.0040 (3) |
C1 | 0.0179 (5) | 0.0146 (5) | 0.0215 (5) | −0.0019 (4) | 0.0045 (4) | −0.0033 (4) |
N2 | 0.0161 (4) | 0.0130 (4) | 0.0216 (4) | −0.0002 (3) | 0.0037 (3) | −0.0028 (3) |
C3 | 0.0171 (5) | 0.0154 (5) | 0.0170 (5) | 0.0004 (4) | 0.0024 (4) | 0.0014 (4) |
C3A | 0.0159 (5) | 0.0141 (4) | 0.0155 (5) | −0.0009 (4) | 0.0033 (4) | 0.0004 (4) |
C4 | 0.0162 (5) | 0.0149 (5) | 0.0197 (5) | 0.0005 (4) | 0.0043 (4) | −0.0010 (4) |
C5 | 0.0189 (5) | 0.0218 (5) | 0.0187 (5) | 0.0057 (4) | 0.0026 (4) | −0.0001 (4) |
C6 | 0.0276 (6) | 0.0197 (5) | 0.0219 (5) | 0.0043 (4) | 0.0058 (4) | 0.0064 (4) |
C7 | 0.0251 (6) | 0.0176 (5) | 0.0206 (5) | −0.0011 (4) | 0.0076 (4) | 0.0032 (4) |
C7A | 0.0199 (5) | 0.0121 (4) | 0.0168 (5) | −0.0010 (4) | 0.0062 (4) | −0.0016 (4) |
C8 | 0.0186 (5) | 0.0146 (5) | 0.0168 (5) | 0.0016 (4) | 0.0049 (4) | 0.0014 (4) |
C9 | 0.0198 (5) | 0.0204 (5) | 0.0184 (5) | 0.0002 (4) | 0.0038 (4) | −0.0022 (4) |
C10 | 0.0193 (5) | 0.0250 (6) | 0.0221 (5) | 0.0026 (4) | 0.0054 (4) | 0.0013 (4) |
C11 | 0.0248 (6) | 0.0204 (5) | 0.0237 (5) | 0.0050 (4) | 0.0114 (4) | 0.0028 (4) |
C12 | 0.0284 (6) | 0.0162 (5) | 0.0215 (5) | −0.0003 (4) | 0.0099 (4) | −0.0008 (4) |
C13 | 0.0223 (5) | 0.0159 (5) | 0.0190 (5) | −0.0008 (4) | 0.0053 (4) | −0.0003 (4) |
C14 | 0.0160 (5) | 0.0193 (5) | 0.0263 (6) | 0.0002 (4) | 0.0053 (4) | −0.0027 (4) |
C15 | 0.0310 (7) | 0.0203 (6) | 0.0432 (8) | −0.0081 (5) | 0.0118 (6) | 0.0019 (5) |
C16 | 0.0265 (6) | 0.0311 (6) | 0.0201 (5) | 0.0015 (5) | 0.0012 (4) | −0.0032 (5) |
C17 | 0.0345 (7) | 0.0412 (8) | 0.0265 (6) | 0.0057 (6) | 0.0023 (5) | −0.0109 (6) |
C18 | 0.0236 (5) | 0.0140 (5) | 0.0222 (5) | −0.0007 (4) | 0.0048 (4) | −0.0016 (4) |
C19 | 0.0324 (6) | 0.0205 (5) | 0.0307 (6) | −0.0020 (5) | 0.0104 (5) | −0.0097 (5) |
O1—C3 | 1.2137 (13) | C6—H6B | 0.9900 |
O2—C14 | 1.2034 (14) | C7—C7A | 1.5315 (15) |
O3—C14 | 1.3446 (14) | C7—H7A | 0.9900 |
O3—C15 | 1.4433 (14) | C7—H7B | 0.9900 |
O4—C16 | 1.3438 (14) | C8—C9 | 1.3964 (15) |
O4—C5 | 1.4536 (13) | C8—C13 | 1.3970 (15) |
O5—C16 | 1.2066 (15) | C9—C10 | 1.3893 (15) |
O6—C18 | 1.3548 (13) | C9—H9 | 0.9500 |
O6—C7A | 1.4552 (12) | C10—C11 | 1.3847 (17) |
O7—C18 | 1.2034 (14) | C10—H10 | 0.9500 |
C1—N2 | 1.4705 (13) | C11—C12 | 1.3915 (17) |
C1—C7A | 1.5329 (15) | C11—H11 | 0.9500 |
C1—H1A | 0.9900 | C12—C13 | 1.3897 (16) |
C1—H1B | 0.9900 | C12—H12 | 0.9500 |
N2—C3 | 1.3776 (14) | C13—H13 | 0.9500 |
N2—C8 | 1.4121 (13) | C15—H15A | 0.9800 |
C3—C3A | 1.5232 (15) | C15—H15B | 0.9800 |
C3A—C7A | 1.5326 (14) | C15—H15C | 0.9800 |
C3A—C4 | 1.5336 (15) | C16—C17 | 1.4992 (18) |
C3A—H3A | 1.0000 | C17—H17A | 0.9800 |
C4—C14 | 1.5161 (15) | C17—H17B | 0.9800 |
C4—C5 | 1.5226 (15) | C17—H17C | 0.9800 |
C4—H4 | 1.0000 | C18—C19 | 1.4949 (16) |
C5—C6 | 1.5176 (17) | C19—H19A | 0.9800 |
C5—H5 | 1.0000 | C19—H19B | 0.9800 |
C6—C7 | 1.5218 (16) | C19—H19C | 0.9800 |
C6—H6A | 0.9900 | ||
C14—O3—C15 | 115.72 (10) | O6—C7A—C1 | 112.49 (9) |
C16—O4—C5 | 118.23 (9) | C7—C7A—C1 | 111.83 (9) |
C18—O6—C7A | 118.17 (8) | C3A—C7A—C1 | 102.28 (8) |
N2—C1—C7A | 102.29 (8) | C9—C8—C13 | 119.72 (10) |
N2—C1—H1A | 111.3 | C9—C8—N2 | 119.05 (9) |
C7A—C1—H1A | 111.3 | C13—C8—N2 | 121.21 (10) |
N2—C1—H1B | 111.3 | C10—C9—C8 | 120.05 (10) |
C7A—C1—H1B | 111.3 | C10—C9—H9 | 120.0 |
H1A—C1—H1B | 109.2 | C8—C9—H9 | 120.0 |
C3—N2—C8 | 125.34 (9) | C11—C10—C9 | 120.45 (11) |
C3—N2—C1 | 112.51 (9) | C11—C10—H10 | 119.8 |
C8—N2—C1 | 121.44 (9) | C9—C10—H10 | 119.8 |
O1—C3—N2 | 126.48 (10) | C10—C11—C12 | 119.46 (10) |
O1—C3—C3A | 126.50 (10) | C10—C11—H11 | 120.3 |
N2—C3—C3A | 106.91 (9) | C12—C11—H11 | 120.3 |
C3—C3A—C7A | 103.73 (8) | C13—C12—C11 | 120.83 (10) |
C3—C3A—C4 | 115.66 (9) | C13—C12—H12 | 119.6 |
C7A—C3A—C4 | 115.84 (8) | C11—C12—H12 | 119.6 |
C3—C3A—H3A | 107.0 | C12—C13—C8 | 119.48 (10) |
C7A—C3A—H3A | 107.0 | C12—C13—H13 | 120.3 |
C4—C3A—H3A | 107.0 | C8—C13—H13 | 120.3 |
C14—C4—C5 | 112.22 (9) | O2—C14—O3 | 124.43 (11) |
C14—C4—C3A | 112.21 (9) | O2—C14—C4 | 125.04 (11) |
C5—C4—C3A | 112.46 (9) | O3—C14—C4 | 110.47 (9) |
C14—C4—H4 | 106.5 | O3—C15—H15A | 109.5 |
C5—C4—H4 | 106.5 | O3—C15—H15B | 109.5 |
C3A—C4—H4 | 106.5 | H15A—C15—H15B | 109.5 |
O4—C5—C6 | 108.81 (9) | O3—C15—H15C | 109.5 |
O4—C5—C4 | 106.82 (9) | H15A—C15—H15C | 109.5 |
C6—C5—C4 | 109.97 (9) | H15B—C15—H15C | 109.5 |
O4—C5—H5 | 110.4 | O5—C16—O4 | 123.61 (12) |
C6—C5—H5 | 110.4 | O5—C16—C17 | 126.23 (12) |
C4—C5—H5 | 110.4 | O4—C16—C17 | 110.16 (10) |
C5—C6—C7 | 111.04 (9) | C16—C17—H17A | 109.5 |
C5—C6—H6A | 109.4 | C16—C17—H17B | 109.5 |
C7—C6—H6A | 109.4 | H17A—C17—H17B | 109.5 |
C5—C6—H6B | 109.4 | C16—C17—H17C | 109.5 |
C7—C6—H6B | 109.4 | H17A—C17—H17C | 109.5 |
H6A—C6—H6B | 108.0 | H17B—C17—H17C | 109.5 |
C6—C7—C7A | 113.04 (9) | O7—C18—O6 | 123.80 (10) |
C6—C7—H7A | 109.0 | O7—C18—C19 | 125.60 (11) |
C7A—C7—H7A | 109.0 | O6—C18—C19 | 110.60 (10) |
C6—C7—H7B | 109.0 | C18—C19—H19A | 109.5 |
C7A—C7—H7B | 109.0 | C18—C19—H19B | 109.5 |
H7A—C7—H7B | 107.8 | H19A—C19—H19B | 109.5 |
O6—C7A—C7 | 111.22 (8) | C18—C19—H19C | 109.5 |
O6—C7A—C3A | 105.19 (8) | H19A—C19—H19C | 109.5 |
C7—C7A—C3A | 113.38 (9) | H19B—C19—H19C | 109.5 |
C7A—C1—N2—C3 | −23.81 (11) | C4—C3A—C7A—O6 | 82.25 (10) |
C7A—C1—N2—C8 | 165.34 (9) | C3—C3A—C7A—C7 | 88.38 (10) |
C8—N2—C3—O1 | −2.61 (18) | C4—C3A—C7A—C7 | −39.48 (12) |
C1—N2—C3—O1 | −173.04 (11) | C3—C3A—C7A—C1 | −32.19 (10) |
C8—N2—C3—C3A | 173.69 (9) | C4—C3A—C7A—C1 | −160.05 (9) |
C1—N2—C3—C3A | 3.26 (12) | N2—C1—C7A—O6 | 145.93 (8) |
O1—C3—C3A—C7A | −164.92 (11) | N2—C1—C7A—C7 | −88.07 (10) |
N2—C3—C3A—C7A | 18.78 (11) | N2—C1—C7A—C3A | 33.57 (10) |
O1—C3—C3A—C4 | −36.95 (15) | C3—N2—C8—C9 | −149.57 (11) |
N2—C3—C3A—C4 | 146.75 (9) | C1—N2—C8—C9 | 20.06 (15) |
C3—C3A—C4—C14 | 51.02 (12) | C3—N2—C8—C13 | 31.90 (16) |
C7A—C3A—C4—C14 | 172.71 (9) | C1—N2—C8—C13 | −158.47 (10) |
C3—C3A—C4—C5 | −76.63 (11) | C13—C8—C9—C10 | −1.15 (16) |
C7A—C3A—C4—C5 | 45.06 (12) | N2—C8—C9—C10 | −179.70 (10) |
C16—O4—C5—C6 | −100.66 (11) | C8—C9—C10—C11 | 0.60 (17) |
C16—O4—C5—C4 | 140.66 (10) | C9—C10—C11—C12 | 0.30 (17) |
C14—C4—C5—O4 | −64.68 (11) | C10—C11—C12—C13 | −0.66 (17) |
C3A—C4—C5—O4 | 62.96 (11) | C11—C12—C13—C8 | 0.11 (16) |
C14—C4—C5—C6 | 177.40 (9) | C9—C8—C13—C12 | 0.79 (16) |
C3A—C4—C5—C6 | −54.96 (12) | N2—C8—C13—C12 | 179.31 (10) |
O4—C5—C6—C7 | −55.63 (12) | C15—O3—C14—O2 | 12.04 (17) |
C4—C5—C6—C7 | 61.05 (12) | C15—O3—C14—C4 | −170.57 (9) |
C5—C6—C7—C7A | −56.34 (13) | C5—C4—C14—O2 | −7.30 (16) |
C18—O6—C7A—C7 | −71.68 (12) | C3A—C4—C14—O2 | −135.08 (12) |
C18—O6—C7A—C3A | 165.19 (9) | C5—C4—C14—O3 | 175.33 (9) |
C18—O6—C7A—C1 | 54.65 (12) | C3A—C4—C14—O3 | 47.55 (12) |
C6—C7—C7A—O6 | −73.57 (11) | C5—O4—C16—O5 | 4.05 (19) |
C6—C7—C7A—C3A | 44.73 (12) | C5—O4—C16—C17 | −175.72 (11) |
C6—C7—C7A—C1 | 159.74 (9) | C7A—O6—C18—O7 | 1.55 (16) |
C3—C3A—C7A—O6 | −149.89 (8) | C7A—O6—C18—C19 | −178.41 (9) |
D—H···A | D—H | H···A | D···A | D—H···A |
C3A—H3A···O3i | 1.00 | 2.55 | 3.4135 (13) | 144 |
C12—H12···O2ii | 0.95 | 2.46 | 3.2812 (15) | 145 |
Symmetry codes: (i) −x+1, y, −z+3/2; (ii) −x+1, −y, −z+1. |
D—H···A | D—H | H···A | D···A | D—H···A |
C3A—H3A···O3i | 1.00 | 2.55 | 3.4135 (13) | 144 |
C12—H12···O2ii | 0.95 | 2.46 | 3.2812 (15) | 145 |
Symmetry codes: (i) −x+1, y, −z+3/2; (ii) −x+1, −y, −z+1. |
Acknowledgements
The authors are grateful to the Russian Foundation for Basic Research for financial support of this work (grant No. 12-03-31088-a).
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This is an open-access article distributed under the terms of the Creative Commons Attribution (CC-BY) Licence, which permits unrestricted use, distribution, and reproduction in any medium, provided the original authors and source are cited.
3a,6-Epoxyisoindoles, which are very easy prepared by intramolecular Diels-Alder reaction of furan (IMDAF) (Vogel et al., 1999; Zubkov et al., 2005), find a wide application for synthesis of various complicated natural-like molecules (Balthaser et al., 2011; Zubkov et al., 2011). Most of these transformations proceed via electrophilic or nucleophilic opening of the epoxy bridge. As a rule, the first leads to aromatic compounds, whereas the latter gives rise to perhydroisoindoles with several (three or four) asymmetric centers in mild conditions (Zubkov et al., 2009, 2012; Claeys et al., 2010). Stereochemistry of the nucleophilic process is hardly predictable, because it depends on mechanism of the reaction (SN1 or SN2).
This work clarifies a question concerning mechanism (SN2) and stereochemistry of a nucleophilic cleavage of 3a,6-epoxy bridge in 1-oxo-2-phenyloctahydro-3a,6-epoxyisoindole-7-carboxylate (Fig. 1). The structure of final product – methyl 5,7a-bis(acetyloxy)-3-oxo-2-phenyloctahydro-1H-isoindole- 4-carboxylate, C20H23NO7, was established by X-ray diffraction study.
Molecule of the title compound comprises a cis-fused bicyclic system containing one five-membered (2-pyrrolidinone) and one six-membered (cyclohexane) rings (Fig. 2). The five-membered ring has envelope conformation (the C7A carbon atom is out of the plane through the other atoms of the ring by 0.540 (2) Å), and the six-membered ring adopts chair conformation. The carboxylate substituent at the C4 carbon atom occupies the equatorial position, whereas the two acetyloxy substituents at the C5 and C7A carbon atoms are in the sterically unfavorable axial positions. Such disposition is explained by the direction of the nucleophilic cleavage of 3a,6-epoxy bridge in the initial 1-oxo-2-phenyloctahydro-3a,6-epoxyisoindole-7-carboxylate. The nitrogen N2 atom has a trigonal-planar geometry (sum of the bond angles is 359.3 (3)°). The dihedral angle between the planar part of the pyrrolidinone ring and phenyl ring plane is 25.98 (6)°.
The molecule of the title compound> possesses four asymmetric centers at the C3A, C4, C5 and C7A carbon atoms and can have potentially numerous diastereomers. The crystal of the title compound is racemic and consists of enantiomeric pairs with the following relative configuration of the centers: rac-3aR*,4S*,5R*,7aR*.
In the crystal, the molecules of the title compound are bound into the zigzag chains along the c axis by the intermolecular C—H···O hydrogen bonds (Figure 3, Table 1).