tert-Butyl (2S,3R,4R)-7′-bromo-4-methyl-2′,5-dioxo-4,5-di­hydro-3H-spiro­[furan-2,3′-indoline]-3-carboxyl­ate

Meng, C.-H.; Xia, A.-B.

doi:10.1107/S2414314617004126

organic compounds

IUCrDATA

ISSN: 2414-3146

Volume 2| Part 3| March 2017| x170412

https://doi.org/10.1107/S2414314617004126

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tert-Butyl (2S,3R,4R)-7′-bromo-4-methyl-2′,5-dioxo-4,5-dihydro-3H-spiro[furan-2,3′-indoline]-3-carboxylate

Chen-Hong Meng ^a and Ai-Bao Xia ^a ^*

^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

Edited by D.-J. Xu, Zhejiang University (Yuquan Campus), China (Received 7 March 2017; accepted 14 March 2017; online 24 March 2017)

In the title compound, C₁₇H₁₈BrNO₅, the furan ring has an envelope conformation 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 envelope conformation 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).

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N1—H1⋯O4ⁱ	0.86	2.15	2.944 (4)	154
C12—H12A⋯O1ⁱⁱ	0.96	2.59	3.415 (6)	144
Symmetry code: (i) x-1, y, z; (ii) x+1, y, z.

Figure 1
The structure of the title compound. Displacement ellipsoids are drawn at the 50% probability level.

Figure 2
The crystal packing of the title compound showing the chain structure. Hydrogen bonds are drawn as dashed lines.

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 chromatography 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 refinement details are summarized in Table 2.

Table 2
Experimental details

Crystal data
Chemical formula	C₁₇H₁₈BrNO₅
M_r	396.23
Crystal system, space group	Orthorhombic, P2₁2₁2₁
Temperature (K)	296
a, b, c (Å)	7.7040 (18), 9.325 (2), 25.540 (6)
V (Å³)	1834.8 (7)
Z	4
Radiation type	Mo Kα
μ (mm⁻¹)	2.27
Crystal size (mm)	0.2 × 0.18 × 0.15

Data collection
Diffractometer	Bruker APEXII CCD
Absorption correction	Multi-scan (SADABS; Bruker, 2009 )
T_min, T_max	0.623, 0.746
No. of measured, independent and observed [I > 2σ(I)] reflections	15033, 4233, 2395
R_int	0.053
(sin θ/λ)_max (Å⁻¹)	0.651

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.042, 0.098, 1.00
No. of reflections	4233
No. of parameters	221
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.31, −0.41
Absolute structure	Flack x determined using 776 quotients [(I⁺)−(I⁻)]/[(I⁺)+(I⁻)] (Parsons et al. (2013 )
Absolute structure parameter	0.045 (8)
Computer programs: APEX2 and SAINT (Bruker, 2009), SHELXT (Sheldrick, 2015a ), SHELXL2016 (Sheldrick, 2015b ) and OLEX2 (Dolomanov et al., 2009 ).

Structural data

CCDC reference: 1537818

Crystal structure: contains datablocks global, I. DOI: https://doi.org/10.1107/S2414314617004126/xu4024sup1.cif

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

checkCIF report

Computing details top

Data collection: APEX2 (Bruker, 2009); cell refinement: 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).

tert-Butyl (2S,3R,4R)-7'-bromo-4-methyl-2',5-dioxo-4,5-dihydro-3H-spiro[furan-2,3'-indoline]-3-carboxylate top

Crystal data top

C₁₇H₁₈BrNO₅	D_x = 1.434 Mg m⁻³
M_r = 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

Data collection top

Bruker APEXII CCD diffractometer	2395 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.053
φ and ω scans	θ_max = 27.6°, θ_min = 2.3°
Absorption correction: multi-scan (SADABS; Bruker, 2009)	h = −8→10
T_min = 0.623, T_max = 0.746	k = −12→12
15033 measured reflections	l = −30→33
4233 independent reflections

Refinement top

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(F_o²) + (0.0197P)² + 0.3907P] where P = (F_o² + 2F_c²)/3
wR(F²) = 0.098	(Δ/σ)_max = 0.005
S = 1.00	Δρ_max = 0.31 e Å⁻³
4233 reflections	Δρ_min = −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

Special details top

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; U_iso(H) = 1.2U_eq of the carrier atoms.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	U_iso*/U_eq
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*

Atomic displacement parameters (Å²) top

	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)

Geometric parameters (Å, º) top

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

Hydrogen-bond geometry (Å, º) top

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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