Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270107056016/ln3060sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S0108270107056016/ln3060Ibsup2.hkl |
CCDC reference: 677211
For related literature, see: Ashimori & Overman (1992); Ashimori et al. (1998); Beletskaya & Cheprakov (2000); Berliner & Hann (1925); Curran & Heffner (1990); Fujikura et al. (1995); Lapierre et al. (2007); Mandin & Overman (1992); McDermott et al. (2006, 2007); Messina et al. (2001); Pauling (1960); Stambuli et al. (2001).
Compound (Ib) was synthesized from 2,4-dimethylaniline using procedures based on the iodination of anilines by Berliner & Hann (1925), and the Takahashi method for the methylation of anilides (Fujikura et al., 1995). Purification was achieved by column chromatography on silica using hexane–dichloromethane (1:1 v/v) as the eluent, and recrystallization from hexane. N-(2-Iodo-4,6-dimethylphenyl)-2-methyl-(2E)-butenamide was obtained as short pale-turquoise needles (8.27 g, 31%, m.p. 382–385 K). Additional details of the synthesis and spectroscopic data are given in the Supplementary material.
H atoms were included in idealized positions and refined using a riding model, with C—H = 0.93 Å and Uiso(H) = 1.2Ueq(C) for the trigonal planar groups, and C—H = 0.96 Å and Uiso(H) = 1.5Ueq(C) for the methyl groups.
Two persistent difference peaks were assigned and refined as partial disordered I atoms, I2 and I3, with site occupancies of 0.0206 (12) and 0.015, respectively. The first of these atoms, I2, is close to C31 and represents a molecule with the phenyl group rotated by 180° about the C2···C5 axis, i.e. with atom I1 and the C31 methyl group interchanged. Consequently, the site occupation factors of atom I1 and the C31 methyl group were constrained to 0.9794 (12), but the minor disorder site for the C31 methyl group was not included in the model.
The second peak was also assigned as a low-occupancy site for an I atom, I3, which lies ca 2.2 Å from atom I1 and quite separate from any other atom. A data set collected from a second crystal showed the same residual electron-density peaks. Examination of reconstructed zero-layer precession images showed severe streaking of the reflections and possibly some satellite reflections. One explanation for these images could be that the crystals consist of stacked plates that are very slightly slipped relative to one another. Consequently, it is likely that the residual peak assigned as atom I3 is an artefact of the data.
In the final difference map, the highest residual peaks (to ca 0.7 e Å-3) were close to the major-occupancy I atom, I1.
Data collection: COLLECT (Nonius, 1998); cell refinement: DENZO (Otwinowski & Minor, 1997) and COLLECT (Nonius, 1998); data reduction: DENZO (Otwinowski & Minor, 1997) and COLLECT (Nonius, 1998); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997); software used to prepare material for publication: SHELXL97 (Sheldrick, 1997).
C14H18INO | V = 715.14 (8) Å3 |
Mr = 343.19 | Z = 2 |
Triclinic, P1 | F(000) = 340 |
a = 8.8872 (6) Å | Dx = 1.594 Mg m−3 |
b = 9.3897 (6) Å | Mo Kα radiation, λ = 0.71073 Å |
c = 10.1875 (7) Å | µ = 2.23 mm−1 |
α = 66.389 (4)° | T = 120 K |
β = 67.135 (4)° | Slab, colourless |
γ = 76.842 (5)° | 0.45 × 0.3 × 0.14 mm |
Bruker Nonius KappaCCD area-detector diffractometer | 3278 independent reflections |
Radiation source: Bruker Nonius FR591 rotating anode | 2812 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.043 |
Detector resolution: 9.091 pixels mm-1 | θmax = 27.5°, θmin = 2.9° |
ϕ and ω scans | h = −11→11 |
Absorption correction: multi-scan (SADABS; Sheldrick, 2003) | k = −12→12 |
Tmin = 0.612, Tmax = 1.00 | l = −13→13 |
15106 measured reflections |
Refinement on F2 | Secondary atom site location: difference Fourier map |
Least-squares matrix: full | Hydrogen site location: inferred from neighbouring sites |
R[F2 > 2σ(F2)] = 0.033 | H-atom parameters constrained |
wR(F2) = 0.086 | w = 1/[σ2(Fo2) + (0.0421P)2 + 0.6769P] where P = (Fo2 + 2Fc2)/3 |
S = 1.14 | (Δ/σ)max = 0.007 |
3278 reflections | Δρmax = 0.73 e Å−3 |
163 parameters | Δρmin = −1.12 e Å−3 |
0 restraints | Extinction correction: SHELXL97 (Sheldrick, 1997), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4 |
Primary atom site location: structure-invariant direct methods | Extinction coefficient: 0.025 (2) |
C14H18INO | γ = 76.842 (5)° |
Mr = 343.19 | V = 715.14 (8) Å3 |
Triclinic, P1 | Z = 2 |
a = 8.8872 (6) Å | Mo Kα radiation |
b = 9.3897 (6) Å | µ = 2.23 mm−1 |
c = 10.1875 (7) Å | T = 120 K |
α = 66.389 (4)° | 0.45 × 0.3 × 0.14 mm |
β = 67.135 (4)° |
Bruker Nonius KappaCCD area-detector diffractometer | 3278 independent reflections |
Absorption correction: multi-scan (SADABS; Sheldrick, 2003) | 2812 reflections with I > 2σ(I) |
Tmin = 0.612, Tmax = 1.00 | Rint = 0.043 |
15106 measured reflections |
R[F2 > 2σ(F2)] = 0.033 | 0 restraints |
wR(F2) = 0.086 | H-atom parameters constrained |
S = 1.14 | Δρmax = 0.73 e Å−3 |
3278 reflections | Δρmin = −1.12 e Å−3 |
163 parameters |
Experimental. The preparation of N-(2-iodo-4,6-dimethylphenyl)-2-methyl-(2E)-butenamide, (Ib), was carried out as follows. By the procedure of Hann (Berliner & Hann, 1925) a round-bottomed flask was charged with 2,4-dimethylaniline [Eguchi, S., Kimoto, H., Okano, T. & Tsuge, H. (1997). J. Chem. Soc., Perkin Trans. 1, pp. 1581–1587; Barluenga, J., Ezquerra, J., Lamas, C., Pedregal, C. & Perez, M. (1996). J. Org. Chem. 61, 5804–5812.] (5 g, 41.26 mmol) and diethyl ether (30 ml). Concentrated hydrochloric acid (10 ml) was added dropwise. The mixture was stirred at room temperature for 30 min and the precipitate which formed was collected by filtration. This aniline hydrogen chloride salt, iodine (11.50 g, 45.39 mmol) and calcium carbonate (6.30 g, 61.89 mmol) were stirred in water–diethyl ether (5:1 v/v, 180 ml) at room temperature for 16 h. Sodium thiosulfate was added directly to the reaction mixture and stirred until the brown colour faded. The product was extracted with ethyl acetate, washed with half brine, dried over magnesium sulfate, filtered, and the solvent removed in vacuo. The crude product was dissolved in dichloromethane (DCM) and filtered through a column containing 20 cm silica over 5 cm magnesium sulfate, using dichloromethane as the eluent. The product was obtained as a brown oil and crystallized from propan-2-ol–water. 4,6-Dimethyl-2-iodoaniline was isolated as brown needle-like crystals (6.64 g, 65%). Spectroscopic analysis: 1H NMR (300 MHz, CDCl3, δ, p.p.m.): 7.27 (1H, s, H3), 6.74 (1H, s, H5), 3.82 (2H, br s, NH2), 2.10 (6H, s, ArCH3); 13C NMR (75 MHz, CDCl3, δ, p.p.m.): 141.6, 136.1, 130.6, 128.4, 121.6, 83.9 (C—I), 18.8 (ArCH3), 17.8 (ArCH3). The procedure was repeated twice. The product (20 g, 80.95 mmol) was dissolved in dry DCM (60 ml) and cooled to 273 K before a solution of 2-methylbut-2-enoyl chloride (9.54 g, 89.04 mmol) in dry DCM (60 ml) was added dropwise from a syringe. Potassium carbonate (16.78 g, 121.4 mmol) was added, and the suspension was allowed to warm to room temperature and stirred for 16 h. Aqueous sodium hydroxide (2 M) was added, and stirring continued for 1 h at room temperature. The organic layer was separated off and the aqueous layer was extracted with DCM. The organic extracts were combined, dried over magnesium sulfate, filtered and the solvent removed in vacuo. Purification was achieved by column chromatography on silica using hexane–DCM (1:1) as the eluent, and recrystallization from hexane. N-(2-Iodo-4,6-dimethylphenyl)-2-methyl-(2E)-butenamide was obtained as pale-turquoise short needles (8.27 g, 31%; m.p. 382–385 K). IR (νmax, thin film, cm-1): 3286, 2981, 2918, 2855, 1662, 1627, 1599, 1557, 1387, 1334, 1284, 1261, 1230, 1150, 1123, 1074, 1041, 1017, 962, 896, 848, 813, 773, 738, 709, 648, 577, 552; 1H NMR (300 MHz, CDCl3, δ, p.p.m.): 7.42 (1H, s, H3), 7.08 (1H, br s, NH), 6.93 (1H, s, H5), 6.58 (1H, q, J = 6.7 Hz, CH3CH═CCH3R), 2.18 (3H, s, ArCH3), 2.14 (3H, s, ArCH3), 1.89 (3H, d, J = 1.0 Hz, CH3CH═CCH3R), 1.74 (3H, dd, J = 6.9 Hz, 1.0, CH3CH═CCH3R); 13C NMR (75 MHz, CDCl3, δ, p.p.m.): 167.6 (C═ O), 138.9, 137.3, 137.0, 134.8, 132.0, 131.9, 99.3 (C—I), 20.3 (ArCH3), 19.5 (ArCH3), 14.0 (CCH3), 12.5 (CCH3); m/z (CI) 347 (45%), 330 (M + H+, 100), 221 (13), 204 (23), 202 (M - I, 6), 188 (8), 83 (3); m/z (EI) 329 (M, 1%), 246 (8), 202 (M - I, 67), 187 (2), 158 (2), 118 (22), 104 (12), 91 (39), 83 (C5H7O, 100), 77 (17), 55 (C4H7, 96); HRMS, found: 330.0355;; C13H17NOI (M + H+) requires: 330.0349. The product (3.50 g, 10.63 mmol) was methylated by the procedure of Takahashi (Fujikura et al., 1995) [which is almost identical to the method described by Curran (Lapierre et al., 2007)] to give N-(2-iodo-4,6-dimethylphenyl)-N,2-dimethyl-(2E)-butenamide, (Ib), as colourless crystals (3.51 g, 96%). 1,3,5,7-Tetramethyl-1-vinyl-1,3-dihydroindol-2-one, (IIb), was prepared as follows. N-(2-iodo-4,6-dimethylphenyl)-N,2-dimethyl-(2E)-butenamide, (Ib), was converted into 1,3,5,7-tetramethyl-1-vinyl-1,3-dihydroindol-2-one (IIb) [m.p. 323–325 K for racemic (IIb)], which corresponded to the product described by Curran (Lapierre et al., 2007). The asymmetric Heck reaction was conducted at 353 K. The enantiomeric excess of (IIb) formed using (R)-BINAP was measured by NMR using approximately 15 mg of (IIb) in CDCl3 (0.75 ml) and a 1 M solution of tris[3-heptafluoropropylhydroxymethylene)-(+)-camphorato]europium(III) in CDCl3, which was added in small portions (a few drops) until a suitable separation of the peaks representing the two enantiomers in the 1H NMR spectrum was obtained. The e.e.s were calculated using the magnitude of the integration of the two peaks for the quaternary methyl group (C1—Me). The product from the reaction using (R)-BINAP had an e.e. of 25%, with the (S)-(-)-1,3,5,7-tetramethyl-1-vinyl-1,3-dihydroindol-2-one, (IIb), predominating [enantiomer ratio = 62.5:37.5 (S):(R)]. |
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 | Occ. (<1) | |
I1 | 0.51658 (3) | 0.05041 (2) | 0.19658 (2) | 0.02860 (12) | 0.9794 (12) |
N2 | 0.2797 (3) | 0.3217 (3) | 0.0346 (3) | 0.0234 (6) | |
C1 | 0.3676 (4) | 0.2376 (4) | 0.2583 (4) | 0.0241 (7) | |
C2 | 0.2815 (4) | 0.3447 (4) | 0.1653 (4) | 0.0222 (6) | |
C3 | 0.2000 (4) | 0.4805 (4) | 0.1958 (4) | 0.0244 (7) | |
C4 | 0.2000 (4) | 0.4988 (4) | 0.3250 (4) | 0.0272 (7) | |
H4 | 0.1443 | 0.5875 | 0.3471 | 0.033* | |
C5 | 0.2796 (4) | 0.3901 (4) | 0.4220 (4) | 0.0272 (7) | |
C6 | 0.3649 (4) | 0.2590 (4) | 0.3861 (4) | 0.0260 (7) | |
H6 | 0.4205 | 0.1852 | 0.4486 | 0.031* | |
C21 | 0.2043 (4) | 0.2062 (4) | 0.0411 (4) | 0.0239 (7) | |
O21 | 0.2347 (3) | 0.1755 (3) | −0.0740 (3) | 0.0280 (5) | |
C22 | 0.0769 (4) | 0.1215 (4) | 0.1856 (4) | 0.0250 (7) | |
C221 | 0.0723 (5) | −0.0463 (4) | 0.2082 (5) | 0.0403 (9) | |
H22A | 0.0116 | −0.1003 | 0.3123 | 0.060* | |
H22B | 0.1821 | −0.0948 | 0.1834 | 0.060* | |
H22C | 0.0202 | −0.0507 | 0.1433 | 0.060* | |
C23 | −0.0332 (4) | 0.1963 (4) | 0.2744 (4) | 0.0282 (7) | |
H23 | −0.0201 | 0.3007 | 0.2487 | 0.034* | |
C24 | −0.1760 (5) | 0.1288 (5) | 0.4113 (5) | 0.0420 (9) | |
H24A | −0.2761 | 0.1811 | 0.3934 | 0.063* | |
H24B | −0.1702 | 0.1423 | 0.4977 | 0.063* | |
H24C | −0.1732 | 0.0196 | 0.4305 | 0.063* | |
C25 | 0.3947 (5) | 0.4040 (5) | −0.1129 (4) | 0.0342 (8) | |
H25A | 0.4823 | 0.3313 | −0.1455 | 0.051* | |
H25B | 0.4386 | 0.4829 | −0.1041 | 0.051* | |
H25C | 0.3386 | 0.4518 | −0.1859 | 0.051* | |
C31 | 0.1170 (5) | 0.6052 (4) | 0.0891 (6) | 0.0251 (7) | 0.9794 (12) |
H31A | 0.1984 | 0.6653 | 0.0011 | 0.038* | 0.9794 (12) |
H31B | 0.0414 | 0.6725 | 0.1403 | 0.038* | 0.9794 (12) |
H31C | 0.0589 | 0.5565 | 0.0583 | 0.038* | 0.9794 (12) |
C51 | 0.2778 (5) | 0.4138 (5) | 0.5609 (4) | 0.0365 (8) | |
H51A | 0.3727 | 0.4646 | 0.5357 | 0.055* | |
H51B | 0.2790 | 0.3145 | 0.6402 | 0.055* | |
H51C | 0.1806 | 0.4774 | 0.5949 | 0.055* | |
I2 | 0.1355 (13) | 0.6249 (7) | 0.0334 (8) | 0.034 (5)* | 0.0206 (12) |
I3 | 0.4489 (13) | −0.1553 (5) | 0.4115 (7) | 0.033 (3)* | 0.015 |
U11 | U22 | U33 | U12 | U13 | U23 | |
I1 | 0.02867 (16) | 0.02619 (16) | 0.02963 (16) | 0.00385 (9) | −0.00859 (10) | −0.01280 (10) |
N2 | 0.0265 (14) | 0.0258 (14) | 0.0172 (13) | −0.0035 (11) | −0.0052 (11) | −0.0084 (11) |
C1 | 0.0203 (15) | 0.0234 (16) | 0.0259 (16) | −0.0023 (12) | −0.0029 (13) | −0.0103 (13) |
C2 | 0.0223 (15) | 0.0233 (16) | 0.0197 (15) | −0.0038 (12) | −0.0034 (12) | −0.0087 (13) |
C3 | 0.0235 (15) | 0.0248 (16) | 0.0235 (16) | −0.0039 (12) | −0.0045 (13) | −0.0091 (13) |
C4 | 0.0271 (16) | 0.0263 (17) | 0.0278 (17) | −0.0041 (13) | −0.0027 (14) | −0.0142 (14) |
C5 | 0.0252 (16) | 0.0333 (18) | 0.0215 (16) | −0.0070 (14) | −0.0017 (13) | −0.0114 (14) |
C6 | 0.0246 (16) | 0.0300 (17) | 0.0230 (16) | −0.0036 (13) | −0.0082 (13) | −0.0080 (14) |
C21 | 0.0232 (15) | 0.0221 (16) | 0.0256 (16) | 0.0047 (12) | −0.0081 (13) | −0.0111 (13) |
O21 | 0.0330 (13) | 0.0279 (12) | 0.0269 (12) | 0.0044 (10) | −0.0111 (10) | −0.0158 (10) |
C22 | 0.0274 (16) | 0.0221 (16) | 0.0261 (16) | −0.0036 (13) | −0.0108 (13) | −0.0064 (13) |
C221 | 0.048 (2) | 0.0277 (19) | 0.044 (2) | −0.0078 (16) | −0.0102 (19) | −0.0140 (17) |
C23 | 0.0257 (16) | 0.0284 (17) | 0.0307 (18) | −0.0066 (13) | −0.0085 (14) | −0.0092 (14) |
C24 | 0.033 (2) | 0.051 (2) | 0.039 (2) | −0.0127 (17) | −0.0001 (17) | −0.0185 (19) |
C25 | 0.039 (2) | 0.041 (2) | 0.0227 (17) | −0.0126 (16) | −0.0043 (15) | −0.0115 (15) |
C31 | 0.032 (2) | 0.0188 (17) | 0.030 (3) | 0.0035 (14) | −0.0163 (17) | −0.0111 (15) |
C51 | 0.039 (2) | 0.047 (2) | 0.0267 (18) | −0.0037 (17) | −0.0077 (16) | −0.0200 (17) |
I1—C1 | 2.101 (3) | C22—C221 | 1.506 (5) |
N2—C21 | 1.367 (4) | C221—H22A | 0.9600 |
N2—C25 | 1.461 (4) | C221—H22B | 0.9600 |
C1—C6 | 1.386 (5) | C221—H22C | 0.9600 |
C1—C2 | 1.395 (5) | C23—C24 | 1.496 (5) |
C2—C3 | 1.403 (4) | C23—H23 | 0.9300 |
C2—N2 | 1.438 (4) | C24—H24A | 0.9600 |
C3—C4 | 1.394 (5) | C24—H24B | 0.9600 |
C3—C31 | 1.519 (5) | C24—H24C | 0.9600 |
C3—I2 | 1.868 (5) | C25—H25A | 0.9600 |
C4—C5 | 1.387 (5) | C25—H25B | 0.9600 |
C4—H4 | 0.9300 | C25—H25C | 0.9600 |
C5—C6 | 1.395 (5) | C31—H31A | 0.9600 |
C5—C51 | 1.511 (5) | C31—H31B | 0.9600 |
C6—H6 | 0.9300 | C31—H31C | 0.9600 |
C21—O21 | 1.233 (4) | C51—H51A | 0.9600 |
C21—C22 | 1.503 (5) | C51—H51B | 0.9600 |
C22—C23 | 1.334 (5) | C51—H51C | 0.9600 |
C21—N2—C2 | 124.5 (3) | C21—C22—C221 | 114.1 (3) |
C21—N2—C25 | 116.8 (3) | C22—C221—H22A | 109.5 |
C2—N2—C25 | 117.3 (3) | C22—C221—H22B | 109.5 |
C6—C1—C2 | 120.6 (3) | H22A—C221—H22B | 109.5 |
C6—C1—I1 | 119.3 (2) | C22—C221—H22C | 109.5 |
C2—C1—I1 | 120.0 (2) | H22A—C221—H22C | 109.5 |
C1—C2—C3 | 119.7 (3) | H22B—C221—H22C | 109.5 |
C1—C2—N2 | 121.2 (3) | C22—C23—C24 | 126.3 (3) |
C3—C2—N2 | 119.1 (3) | C22—C23—H23 | 116.8 |
C4—C3—C2 | 118.2 (3) | C24—C23—H23 | 116.8 |
C4—C3—C31 | 121.1 (3) | C23—C24—H24A | 109.5 |
C2—C3—C31 | 120.7 (3) | C23—C24—H24B | 109.5 |
C4—C3—I2 | 129.6 (3) | C23—C24—H24C | 109.5 |
C2—C3—I2 | 111.5 (3) | N2—C25—H25A | 109.5 |
C5—C4—C3 | 122.7 (3) | N2—C25—H25B | 109.5 |
C5—C4—H4 | 118.6 | H25A—C25—H25B | 109.5 |
C3—C4—H4 | 118.6 | N2—C25—H25C | 109.5 |
C4—C5—C6 | 118.0 (3) | H25A—C25—H25C | 109.5 |
C4—C5—C51 | 121.4 (3) | H25B—C25—H25C | 109.5 |
C6—C5—C51 | 120.6 (3) | C3—C31—H31A | 109.5 |
C1—C6—C5 | 120.7 (3) | C3—C31—H31B | 109.5 |
C1—C6—H6 | 119.7 | C3—C31—H31C | 109.5 |
C5—C6—H6 | 119.7 | C5—C51—H51A | 109.5 |
O21—C21—N2 | 120.1 (3) | C5—C51—H51B | 109.5 |
O21—C21—C22 | 119.2 (3) | H51A—C51—H51B | 109.5 |
N2—C21—C22 | 120.6 (3) | C5—C51—H51C | 109.5 |
C23—C22—C21 | 121.5 (3) | H51A—C51—H51C | 109.5 |
C23—C22—C221 | 124.0 (3) | H51B—C51—H51C | 109.5 |
C6—C1—C2—C3 | 4.1 (5) | C4—C5—C6—C1 | −0.9 (5) |
I1—C1—C2—C3 | −171.5 (2) | C51—C5—C6—C1 | −179.5 (3) |
C6—C1—C2—N2 | −178.3 (3) | C1—C2—N2—C21 | 68.2 (4) |
I1—C1—C2—N2 | 6.1 (4) | C3—C2—N2—C21 | −114.1 (4) |
C1—C2—C3—C4 | −3.8 (5) | C1—C2—N2—C25 | −97.7 (4) |
N2—C2—C3—C4 | 178.5 (3) | C3—C2—N2—C25 | 79.9 (4) |
C1—C2—C3—C31 | 175.0 (3) | C2—N2—C21—O21 | −165.9 (3) |
N2—C2—C3—C31 | −2.7 (5) | C25—N2—C21—O21 | 0.1 (5) |
C1—C2—C3—I2 | 167.0 (4) | C2—N2—C21—C22 | 17.6 (5) |
N2—C2—C3—I2 | −10.7 (5) | C25—N2—C21—C22 | −176.4 (3) |
C2—C3—C4—C5 | 1.3 (5) | O21—C21—C22—C23 | −137.0 (3) |
C31—C3—C4—C5 | −177.5 (3) | N2—C21—C22—C23 | 39.6 (5) |
I2—C3—C4—C5 | −167.6 (5) | O21—C21—C22—C221 | 35.4 (4) |
C3—C4—C5—C6 | 1.1 (5) | N2—C21—C22—C221 | −148.0 (3) |
C3—C4—C5—C51 | 179.7 (3) | C21—C22—C23—C24 | 173.1 (3) |
C2—C1—C6—C5 | −1.7 (5) | C221—C22—C23—C24 | 1.4 (6) |
I1—C1—C6—C5 | 173.9 (2) |
Experimental details
Crystal data | |
Chemical formula | C14H18INO |
Mr | 343.19 |
Crystal system, space group | Triclinic, P1 |
Temperature (K) | 120 |
a, b, c (Å) | 8.8872 (6), 9.3897 (6), 10.1875 (7) |
α, β, γ (°) | 66.389 (4), 67.135 (4), 76.842 (5) |
V (Å3) | 715.14 (8) |
Z | 2 |
Radiation type | Mo Kα |
µ (mm−1) | 2.23 |
Crystal size (mm) | 0.45 × 0.3 × 0.14 |
Data collection | |
Diffractometer | Bruker Nonius KappaCCD area-detector diffractometer |
Absorption correction | Multi-scan (SADABS; Sheldrick, 2003) |
Tmin, Tmax | 0.612, 1.00 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 15106, 3278, 2812 |
Rint | 0.043 |
(sin θ/λ)max (Å−1) | 0.651 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.033, 0.086, 1.14 |
No. of reflections | 3278 |
No. of parameters | 163 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.73, −1.12 |
Computer programs: , DENZO (Otwinowski & Minor, 1997) and COLLECT (Nonius, 1998), SHELXS97 (Sheldrick, 1997), SHELXL97 (Sheldrick, 1997), ORTEP-3 for Windows (Farrugia, 1997).
Starting material | R1 | R2 | Conformationa | N-Aryl | Amide | Acrylate | Acrylate | Alkene | Temp | Product | Ref. |
(N-aryl bond/amide | bond | bond | bond | bond | bond | (K) | |||||
bond/acrylate bond) | C1—C2— | C2—N2— | N2—C21— | O21—C21— | C21—C22— | ||||||
N2—C21)b | C21—C22)c | C22—C23)d | C22—C23) | C23—C24)e | |||||||
(°) | (°) | (°) | (°) | (°) | |||||||
(Ia) (homochiralf) | H | H | (Pg,Ph) +ac/–sp/–sc | +117.3 (7)i | –17.9 (9)i | –51.4 (9)i | +125.1 (7)i | –172.1 (7)i | 140 | (2a) | i |
(homochiralf) | (M,M) –ac/+sp/+sc | –116.5 (3)i | +16.3 (4)i | +52.9 (4)i | –125.3 (3)i | +172.5 (3)i | 293 | i | |||
(Ib) (racemicj) | Me | Me | (P,M) +sc/+sp/+sc | +68.1 (5)k | +17.5 (5)k | +39.9 (5)k | –136.6 (4)k | +173.1 (4)k | 120 | (2b)k,l | k this work |
(racemicj) | (M,P) –sc/–sp/–sc | –68.1 (5)k | –17.5 (5)k | –39.9 (5)k | +136.6 (4)k | –173.1 (4)k | l | ||||
(1c) (homochiralf) | Me | Br | (P,M) +sc/+sp/+sc | +71.1l | +10.2l | +49.2l | –130.7l | +173.1l | 100 | (2c)k | l |
Notes: (a) See McDermott et al. (2006) and Lapierre et al. (2007). The conformational differences through the sequence of atoms C1–C23 can be assigned from a series of three torsion angles, C1—C2—N2—C21, C2—N2—C21—C22 and N2—C21—C22—C23, selected for this purpose. (b) Shows the relationship between the arene and E-amide planes illustrated in the scheme. (c) Shows the deviation from planarity in the amide (a small angle or zero for C2—N2—C21—C22 corresponds to an E-amide). (d) Shows the relationship between the E-amide and alkene planes illustrated in the scheme. (e) Shows the deviation from planarity in the alkene. (f) Data for (P) and (M) forms, measured individually from enantiomerically pure crystals. (g) The (P) configuration corresponds to a positive torsion angle for C1—C2—N2—C21. (h) The (P) configuration corresponds to a positive torsion angle for O21—C21—C22—C23. (i) McDermott et al. (2006). (j) Values for (P) and (M) forms taken from data for a racemic crystal. (k) This work. (l) Lapierre et al. (2007). |
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The (M) enantiomer of the title iodoanilide, (Ib), gives rise (Lapierre et al., 2007), predominantly, to the (R)-1,3-dihydroindol-2-one, (IIb), when cyclized (see scheme) using an intramolecular Heck reaction (Beletskaya & Cheprakov, 2000) under Hartwig's low-temperature conditions (Stambuli et al., 2001). The crystallographic study reported in that work (Lapierre et al., 2007) employed a 4-bromo-2-iodoaryl analogue, (Ic), not the 2,4-dimethyl substrate itself. Furthermore, the conformation adopted in the solid state for the 4-bromo case was different from that which we had described earlier (McDermott et al., 2006) for Overman's original substrate (Ia) (Ashimori & Overman, 1992; Mandin & Overman, 1992; Ashimori et al., 1998) and a symmetrized analogue.
The structure now defined for (Ib) (Fig. 1) resembles that needed (McDermott et al., 2006) for cyclization, except that rotation about C21—C22 is required. Our crystallographic results for (Ia) (McDermott et al., 2006) and (Ib), however, indicate that strong intermolecular I···O interactions (Messina et al., 2001) are present [3.071 (6) Å in (Ia) and 2.964 (3) Å in (Ib)], significantly shorter than the sum of the van der Waals radii (3.55 Å; Pauling, 1960). Unlike (Ia), however, which was characterized as homochiral crystals containing chains of ribbons of +ac/-sp/-sc 2-iodoanilides (Table 1 and Fig. 2) linked by a zigzag pattern of I···O interactions, the title compound crystallizes with the +sc/+sp/+sc conformation and is linked into dimer pairs about an inversion centre through short I···O interactions. The conformations adopted by 2-iodoanilide butenoyl amides of this type are best described (Curran & Heffner, 1990; McDermott et al., 2006) by consideration of three planes (see scheme), corresponding to the three roughly planar sections of the molecule (the aromatic ring, the amide and the alkene). Table 1 compares data for these key features of the molecule.
The 2-iodo-4,6-dimethyl substrate, (Ib), gave the racemic indol-2-one derivative in 86% yield. Reaction of (Ib) with Pd2(dba)3 and (R)-BINAP under Overman's silver phosphate conditions [silver phosphate (Aldrich) in DMA [Please define] (McDermott et al., 2007)] gave the same product, (IIb), with an e.e. [Please define] of 25%. This interconversion is thus consistent with oxidative addition to (P)-(Ib) and pro-(S) coordination of the Re face of the alkene, in the conformation shown in Fig. 1.