organic compounds
tert-Butyl (2S,3R,4R)-7′-bromo-4-methyl-2′,5-dioxo-4,5-dihydro-3H-spiro[furan-2,3′-indoline]-3-carboxylate
aState Key Laboratory Breeding Base of Green Chemistry-Synthesis Technology, Zhejiang University of Technology, Hangzhou 310014, People's Republic of China
*Correspondence e-mail: xiaaibao@zjut.edu.cn
In the title compound, C17H18BrNO5, the furan ring has an with the carboxylate substituted C atom as the flap. The planar indoline ring is inclined to the mean plane of the furan ring by 87.5 (2)°. In the crystal, molecules are linked by N—H⋯O and C—H⋯O hydrogen bonds forming chains propagating along the a-axis direction.
Keywords: crystal structure; γ-lactone; hydrogen bonding.
CCDC reference: 1537818
Structure description
Spirocyclic oxindoles are important structures in many biologically active molecules and natural products (Cui et al., 1996). The key structural characteristic of these compounds is the spiro ring fused at the 3-position of the oxindole core (Cerisoli et al., 2016) with varying degrees of substitution around it (Trost & Brennan, 2009; Wang et al., 2013; Monari et al., 2015). However, it is a challenge to synthesize chiral spirocyclic oxindoles with spiro quaternary centers and multiple chiral centers. Therefore, the development of simply and highly stereoselective methods to synthesize spirooxindoles remains an important research direction for chemists. The title compound was readily synthesized through organocatalytic Michael reaction of propionaldehyde and methyleneindolinones, with subsequent H2O2/K2CO3 system-mediated α-hydroxylation/hemiacetalization cascade reaction under oil/water two-phase conditions, and final oxidative γ-lactonization.
In the title compound, Fig. 1, the furan ring (O2/C7/C9–C11) has an with atom C9 as the flap. The indoline ring (N1/C1–C8) is inclined to the mean plane of the furan ring by 87.5 (2)°. In the crystal, molecules are linked by N—H⋯O and C—H⋯O hydrogen bonds forming chains propagating along the a-axis direction (Table 1 and Fig. 2).
Synthesis and crystallization
To a solution of the chiral catalyst, (S)-2-{diphenyl[(trimethylsilyl)oxy]methyl}pyrrolidine (1.62 mg), carboxybenzene (1.22 mg) and tert-butyl (E)-2-(7-bromo-2-oxoindolin-3-ylidene)acetate (64.8 mg) in 0.5 ml acetonitrile and propionaldehyde (20.0 µl) were introduced via syringe. The mixture was stirred at room temperature. After completion of the reaction (monitored by TLC), the solvent was removed under vacuum and K2CO3 (1 equiv.), [EtOAc (1 ml) and H2O (0.1 ml)], H2O2 (4 equiv.) were added, and the reaction ran at room temperature for 4 h. After completion of the reaction, the mixture was extracted with EtOAc (3 × 5 ml), washed with water, dried and concentrated. The residue and PCC (pyridinium chlorochromate, 2.0 equiv.) in dry DCM (2 ml) was stirred at room temperature for 16 h, then diluted with EtOAc (10 ml). The mixture was filtered and the filtrate concentrated under vacuum and the residue purified by flash on silica gel eluting with petroleum ether/ethyl acetate 4:1 (v/v) to give a white solid. Single crystals were obtained by slow evaporation of a solution in petroleum ether/diethyl ether 5:1 (v/v).
Refinement
Crystal data, data collection and structure .
details are summarized in Table 2Structural data
CCDC reference: 1537818
https://doi.org/10.1107/S2414314617004126/xu4024sup1.cif
contains datablocks global, I. DOI:Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S2414314617004126/xu4024Isup2.hkl
Supporting information file. DOI: https://doi.org/10.1107/S2414314617004126/xu4024Isup3.cml
Data collection: APEX2 (Bruker, 2009); cell
SAINT (Bruker, 2009); data reduction: SAINT (Bruker, 2009); program(s) used to solve structure: SHELXT (Sheldrick, 2015a); program(s) used to refine structure: SHELXL2016 (Sheldrick, 2015b); molecular graphics: OLEX2 (Dolomanov et al., 2009); software used to prepare material for publication: OLEX2 (Dolomanov et al., 2009).C17H18BrNO5 | Dx = 1.434 Mg m−3 |
Mr = 396.23 | Mo Kα radiation, λ = 0.71073 Å |
Orthorhombic, P212121 | Cell parameters from 2454 reflections |
a = 7.7040 (18) Å | θ = 2.7–21.2° |
b = 9.325 (2) Å | µ = 2.27 mm−1 |
c = 25.540 (6) Å | T = 296 K |
V = 1834.8 (7) Å3 | Block, colourless |
Z = 4 | 0.2 × 0.18 × 0.15 mm |
F(000) = 808 |
Bruker APEXII CCD diffractometer | 2395 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.053 |
φ and ω scans | θmax = 27.6°, θmin = 2.3° |
Absorption correction: multi-scan (SADABS; Bruker, 2009) | h = −8→10 |
Tmin = 0.623, Tmax = 0.746 | k = −12→12 |
15033 measured reflections | l = −30→33 |
4233 independent reflections |
Refinement on F2 | Hydrogen site location: inferred from neighbouring sites |
Least-squares matrix: full | H-atom parameters constrained |
R[F2 > 2σ(F2)] = 0.042 | w = 1/[σ2(Fo2) + (0.0197P)2 + 0.3907P] where P = (Fo2 + 2Fc2)/3 |
wR(F2) = 0.098 | (Δ/σ)max = 0.005 |
S = 1.00 | Δρmax = 0.31 e Å−3 |
4233 reflections | Δρmin = −0.41 e Å−3 |
221 parameters | Absolute structure: Flack x determined using 776 quotients [(I+)-(I-)]/[(I+)+(I-)] (Parsons et al. (2013) |
0 restraints | Absolute structure parameter: 0.045 (8) |
Primary atom site location: dual |
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. |
Refinement. H atoms were placed in calculated positions and refined in riding mode with C—H distances 0.93, 0.97 and 0.98 Å, for aryl, methylene and methine H atoms; Uiso(H) = 1.2Ueq of the carrier atoms. |
x | y | z | Uiso*/Ueq | ||
Br1 | 0.15873 (10) | 0.22044 (8) | 0.38775 (3) | 0.1040 (3) | |
O1 | 0.3158 (4) | 0.7880 (4) | 0.37124 (14) | 0.0668 (10) | |
O2 | 0.5385 (4) | 0.7426 (3) | 0.46266 (11) | 0.0491 (8) | |
O3 | 0.6907 (5) | 0.9121 (4) | 0.50236 (13) | 0.0632 (9) | |
O4 | 0.9313 (4) | 0.5704 (4) | 0.35412 (15) | 0.0710 (11) | |
O5 | 0.6721 (4) | 0.5706 (4) | 0.31393 (12) | 0.0589 (9) | |
N1 | 0.2987 (4) | 0.5445 (4) | 0.38441 (15) | 0.0456 (9) | |
H1 | 0.200354 | 0.527700 | 0.369701 | 0.055* | |
C1 | 0.3996 (5) | 0.4405 (5) | 0.40811 (16) | 0.0403 (11) | |
C2 | 0.3682 (7) | 0.2968 (5) | 0.41343 (19) | 0.0555 (13) | |
C3 | 0.4891 (8) | 0.2103 (6) | 0.4385 (2) | 0.0669 (15) | |
H3 | 0.467995 | 0.112717 | 0.442548 | 0.080* | |
C4 | 0.6398 (8) | 0.2692 (6) | 0.4573 (2) | 0.0665 (14) | |
H4 | 0.721780 | 0.210557 | 0.473309 | 0.080* | |
C5 | 0.6716 (7) | 0.4152 (5) | 0.45275 (18) | 0.0541 (12) | |
H5 | 0.773123 | 0.454872 | 0.466110 | 0.065* | |
C6 | 0.5513 (5) | 0.4998 (5) | 0.42830 (17) | 0.0393 (10) | |
C7 | 0.5467 (5) | 0.6563 (5) | 0.41609 (17) | 0.0390 (10) | |
C8 | 0.3726 (5) | 0.6752 (5) | 0.38708 (19) | 0.0438 (10) | |
C9 | 0.7002 (5) | 0.7210 (4) | 0.38479 (17) | 0.0404 (9) | |
H9 | 0.654755 | 0.798353 | 0.362711 | 0.049* | |
C10 | 0.8135 (5) | 0.7878 (5) | 0.42684 (17) | 0.0445 (10) | |
H10 | 0.891596 | 0.714153 | 0.440759 | 0.053* | |
C11 | 0.6835 (6) | 0.8254 (5) | 0.46789 (18) | 0.0448 (11) | |
C12 | 0.9204 (7) | 0.9154 (6) | 0.4098 (2) | 0.0705 (16) | |
H12A | 1.003919 | 0.885478 | 0.384145 | 0.106* | |
H12B | 0.979583 | 0.954926 | 0.439560 | 0.106* | |
H12C | 0.845509 | 0.986824 | 0.394879 | 0.106* | |
C13 | 0.7859 (6) | 0.6122 (5) | 0.34975 (19) | 0.0468 (12) | |
C14 | 0.7091 (8) | 0.4580 (7) | 0.2748 (2) | 0.0746 (17) | |
C15 | 0.5424 (9) | 0.4487 (10) | 0.2447 (3) | 0.148 (4) | |
H15A | 0.447612 | 0.435786 | 0.268690 | 0.223* | |
H15B | 0.547288 | 0.368761 | 0.221100 | 0.223* | |
H15C | 0.525443 | 0.535527 | 0.225212 | 0.223* | |
C16 | 0.7422 (9) | 0.3181 (8) | 0.3026 (3) | 0.101 (2) | |
H16A | 0.844640 | 0.326657 | 0.323833 | 0.151* | |
H16B | 0.758473 | 0.243214 | 0.277316 | 0.151* | |
H16C | 0.644720 | 0.295365 | 0.324514 | 0.151* | |
C17 | 0.8646 (12) | 0.5021 (10) | 0.2419 (3) | 0.150 (4) | |
H17A | 0.838599 | 0.589484 | 0.223605 | 0.225* | |
H17B | 0.890277 | 0.427893 | 0.216985 | 0.225* | |
H17C | 0.963218 | 0.516752 | 0.264217 | 0.225* |
U11 | U22 | U33 | U12 | U13 | U23 | |
Br1 | 0.0990 (5) | 0.0819 (4) | 0.1311 (6) | −0.0540 (4) | −0.0142 (5) | −0.0005 (5) |
O1 | 0.0514 (19) | 0.056 (2) | 0.093 (3) | 0.0064 (18) | −0.0066 (19) | 0.011 (2) |
O2 | 0.0485 (17) | 0.052 (2) | 0.0472 (18) | −0.0080 (16) | 0.0063 (15) | −0.0150 (16) |
O3 | 0.067 (2) | 0.060 (2) | 0.063 (2) | −0.0021 (19) | −0.0095 (19) | −0.0219 (19) |
O4 | 0.037 (2) | 0.086 (3) | 0.090 (3) | −0.0005 (19) | −0.0036 (18) | −0.031 (2) |
O5 | 0.0500 (18) | 0.081 (2) | 0.0455 (19) | 0.004 (2) | −0.0080 (17) | −0.0234 (17) |
N1 | 0.0298 (18) | 0.051 (2) | 0.056 (2) | −0.0074 (16) | −0.0081 (19) | −0.005 (2) |
C1 | 0.040 (2) | 0.040 (2) | 0.041 (3) | −0.004 (2) | 0.008 (2) | 0.000 (2) |
C2 | 0.062 (3) | 0.045 (3) | 0.060 (3) | −0.017 (3) | 0.012 (3) | −0.001 (2) |
C3 | 0.088 (4) | 0.046 (3) | 0.067 (4) | 0.001 (3) | 0.017 (3) | 0.011 (3) |
C4 | 0.072 (4) | 0.063 (4) | 0.065 (3) | 0.016 (3) | 0.006 (3) | 0.015 (3) |
C5 | 0.052 (3) | 0.055 (3) | 0.055 (3) | 0.005 (3) | 0.000 (3) | 0.002 (2) |
C6 | 0.033 (2) | 0.044 (3) | 0.040 (3) | −0.002 (2) | 0.003 (2) | −0.002 (2) |
C7 | 0.034 (2) | 0.044 (3) | 0.039 (3) | −0.0039 (19) | 0.002 (2) | −0.010 (2) |
C8 | 0.033 (2) | 0.049 (2) | 0.050 (3) | −0.0010 (19) | 0.000 (2) | 0.000 (3) |
C9 | 0.035 (2) | 0.045 (2) | 0.041 (2) | −0.0041 (19) | −0.001 (2) | −0.002 (2) |
C10 | 0.036 (2) | 0.043 (2) | 0.055 (3) | −0.007 (2) | −0.005 (2) | −0.005 (2) |
C11 | 0.046 (3) | 0.045 (3) | 0.043 (3) | −0.003 (2) | −0.010 (2) | −0.001 (2) |
C12 | 0.058 (3) | 0.068 (4) | 0.085 (4) | −0.024 (3) | 0.003 (3) | −0.007 (3) |
C13 | 0.037 (3) | 0.059 (3) | 0.044 (3) | −0.012 (2) | 0.004 (2) | −0.001 (2) |
C14 | 0.082 (4) | 0.091 (5) | 0.051 (3) | 0.000 (4) | 0.006 (3) | −0.029 (3) |
C15 | 0.127 (6) | 0.192 (9) | 0.125 (7) | 0.047 (7) | −0.081 (6) | −0.092 (7) |
C16 | 0.090 (5) | 0.096 (6) | 0.116 (5) | −0.007 (4) | 0.003 (4) | −0.046 (5) |
C17 | 0.182 (8) | 0.187 (9) | 0.081 (5) | −0.037 (8) | 0.068 (6) | −0.049 (6) |
Br1—C2 | 1.882 (5) | C7—C9 | 1.550 (6) |
O1—C8 | 1.209 (5) | C9—H9 | 0.9800 |
O2—C7 | 1.438 (5) | C9—C10 | 1.518 (6) |
O2—C11 | 1.364 (5) | C9—C13 | 1.506 (6) |
O3—C11 | 1.196 (5) | C10—H10 | 0.9800 |
O4—C13 | 1.191 (5) | C10—C11 | 1.492 (7) |
O5—C13 | 1.325 (5) | C10—C12 | 1.511 (6) |
O5—C14 | 1.478 (6) | C12—H12A | 0.9600 |
N1—H1 | 0.8600 | C12—H12B | 0.9600 |
N1—C1 | 1.382 (5) | C12—H12C | 0.9600 |
N1—C8 | 1.347 (5) | C14—C15 | 1.498 (8) |
C1—C2 | 1.369 (6) | C14—C16 | 1.508 (10) |
C1—C6 | 1.392 (6) | C14—C17 | 1.520 (9) |
C2—C3 | 1.389 (7) | C15—H15A | 0.9600 |
C3—H3 | 0.9300 | C15—H15B | 0.9600 |
C3—C4 | 1.371 (7) | C15—H15C | 0.9600 |
C4—H4 | 0.9300 | C16—H16A | 0.9600 |
C4—C5 | 1.388 (7) | C16—H16B | 0.9600 |
C5—H5 | 0.9300 | C16—H16C | 0.9600 |
C5—C6 | 1.368 (6) | C17—H17A | 0.9600 |
C6—C7 | 1.493 (6) | C17—H17B | 0.9600 |
C7—C8 | 1.543 (6) | C17—H17C | 0.9600 |
C11—O2—C7 | 111.2 (3) | C11—C10—H10 | 108.8 |
C13—O5—C14 | 123.2 (4) | C11—C10—C12 | 112.6 (4) |
C1—N1—H1 | 124.0 | C12—C10—C9 | 115.6 (4) |
C8—N1—H1 | 124.0 | C12—C10—H10 | 108.8 |
C8—N1—C1 | 112.0 (3) | O2—C11—C10 | 110.4 (4) |
N1—C1—C6 | 110.9 (4) | O3—C11—O2 | 119.5 (4) |
C2—C1—N1 | 129.1 (4) | O3—C11—C10 | 130.2 (4) |
C2—C1—C6 | 120.0 (4) | C10—C12—H12A | 109.5 |
C1—C2—Br1 | 119.2 (4) | C10—C12—H12B | 109.5 |
C1—C2—C3 | 119.7 (5) | C10—C12—H12C | 109.5 |
C3—C2—Br1 | 121.1 (4) | H12A—C12—H12B | 109.5 |
C2—C3—H3 | 120.1 | H12A—C12—H12C | 109.5 |
C4—C3—C2 | 119.8 (5) | H12B—C12—H12C | 109.5 |
C4—C3—H3 | 120.1 | O4—C13—O5 | 126.2 (5) |
C3—C4—H4 | 119.6 | O4—C13—C9 | 125.2 (4) |
C3—C4—C5 | 120.9 (5) | O5—C13—C9 | 108.5 (4) |
C5—C4—H4 | 119.6 | O5—C14—C15 | 102.9 (5) |
C4—C5—H5 | 120.5 | O5—C14—C16 | 109.1 (5) |
C6—C5—C4 | 119.0 (5) | O5—C14—C17 | 109.5 (5) |
C6—C5—H5 | 120.5 | C15—C14—C16 | 109.6 (7) |
C1—C6—C7 | 106.9 (4) | C15—C14—C17 | 114.1 (6) |
C5—C6—C1 | 120.6 (4) | C16—C14—C17 | 111.2 (6) |
C5—C6—C7 | 132.5 (4) | C14—C15—H15A | 109.5 |
O2—C7—C6 | 112.1 (4) | C14—C15—H15B | 109.5 |
O2—C7—C8 | 107.2 (3) | C14—C15—H15C | 109.5 |
O2—C7—C9 | 104.0 (3) | H15A—C15—H15B | 109.5 |
C6—C7—C8 | 103.5 (3) | H15A—C15—H15C | 109.5 |
C6—C7—C9 | 118.1 (4) | H15B—C15—H15C | 109.5 |
C8—C7—C9 | 111.8 (3) | C14—C16—H16A | 109.5 |
O1—C8—N1 | 128.2 (4) | C14—C16—H16B | 109.5 |
O1—C8—C7 | 125.1 (4) | C14—C16—H16C | 109.5 |
N1—C8—C7 | 106.8 (4) | H16A—C16—H16B | 109.5 |
C7—C9—H9 | 108.1 | H16A—C16—H16C | 109.5 |
C10—C9—C7 | 103.5 (3) | H16B—C16—H16C | 109.5 |
C10—C9—H9 | 108.1 | C14—C17—H17A | 109.5 |
C13—C9—C7 | 112.2 (3) | C14—C17—H17B | 109.5 |
C13—C9—H9 | 108.1 | C14—C17—H17C | 109.5 |
C13—C9—C10 | 116.4 (4) | H17A—C17—H17B | 109.5 |
C9—C10—H10 | 108.8 | H17A—C17—H17C | 109.5 |
C11—C10—C9 | 102.0 (3) | H17B—C17—H17C | 109.5 |
D—H···A | D—H | H···A | D···A | D—H···A |
N1—H1···O4i | 0.86 | 2.15 | 2.944 (4) | 154 |
Symmetry code: (i) x−1, y, z. |
Funding information
Funding for this research was provided by: Zhejiang Key Course of Chemical Engineering and Technology, Zhejiang University of Technology.
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