organic compounds\(\def\hfill{\hskip 5em}\def\hfil{\hskip 3em}\def\eqno#1{\hfil {#1}}\)

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(E)-1-[1-(3-Phenyl­cyclo­penta-2,4-dien-1-yl­­idene)eth­yl]pyrrolidine

aDepartment of Chemistry & Chemistry Research Center, United States Air Force, Academy, Colorado Springs, CO 80840, USA
*Correspondence e-mail: scott.iacono@usafa.edu

Edited by J. Simpson, University of Otago, New Zealand (Received 2 May 2018; accepted 22 May 2018; online 5 June 2018)

The title compound, C17H19N, is a disubstituted penta­fulvene obtained from the hydro­amination of 1-phenyl-3-tri­methyl­silylethynyl­cyclo­penta­diene and has monoclinic P21/n symmetry at 100 K. C—H⋯π ring inter­actions between neighboring mol­ecules consolidate the packing. To the authors' knowledge, this reaction is the first reported example of a non-transition metal catalyzed hydro­amination with concomitant desilylation.

3D view (loading...)
[Scheme 3D1]
Chemical scheme
[Scheme 1]

Structure description

The title compound (Fig. 1[link]) crystallizes in the monoclinic space group P21/n with one mol­ecule in the asymmetric unit. Within the fulvene system, the expected alternating short and long bond distances as well as intra-ring bond angles were observed. The 2-phenyl substituent is rotated 24.24 (6)° from the fulvene plane. The geometry around N1 is trigonal planar and the N1/C14/C17 plane is rotated by only 15.42 (9)° from the fulvene plane, presumably to allow partial conjugation of the nitro­gen lone pair into the fulvene π system. Only two broad peaks are observed for the pyrrolidine methyl­ene protons in the 1H NMR spectrum, indicating N—C bond rotation and nitro­gen inversion on the NMR timescale. C—H⋯π ring inter­actions (Table 1[link], Fig. 2[link]) between neighboring mol­ecules consolidate the packing.

Table 1
Hydrogen-bond geometry (Å, °)

Cg2 and Cg3 are the centroids of the C1–C5 and C7–C12 rings, respectively.

D—H⋯A D—H H⋯A DA D—H⋯A
C11—H11⋯Cg3i 0.95 2.75 3.4505 (7) 131
C13—H13CCg2ii 0.98 2.70 3.5435 (7) 145
C17—H17ACg2iii 0.99 2.67 3.6104 (7) 159
Symmetry codes: (i) [-x+{\script{1\over 2}}, y+{\script{1\over 2}}, -z+{\script{1\over 2}}]; (ii) -x, -y+2, -z; (iii) -x, -y+1, -z.
[Figure 1]
Figure 1
The mol­ecular structure of the title compound. Displacement ellipsoids are shown at the 50% probability level.
[Figure 2]
Figure 2
The crystal packing of the title compound, viewed along the a axis. Displacement ellipsoids are shown at the 50% probability level. C—H⋯π ring inter­actions are shown as dashed lines.

Synthesis and crystallization

Synthesis of 1-phenyl-3-tri­methyl­silylethynyl­cyclo­penta­diene. To a vigorously stirred solution of ethynyltri­methyl­silane (7.0 ml, 50.6 mmol) in anhydrous Et2O (25 ml) at −94°C under N2, n-BuLi (2.5 M, 19.2 ml, 48.0 mmol) was added dropwise over 20 min. and allowed to stir for 1 h. A solution of 3-phenyl­cyclo­pent-2-en-1-one (3.99 g, 25.2 mmol) in anhydrous Et2O (250 ml) was added dropwise over 20 min. The resulting solution was allowed to come to room temperature and stirred under N2 for 24 h, then exposed to air. The solvent was removed by rotary evaporation and the residue dissolved in CH2Cl2 (100 ml). 1 M H2SO4 (100 ml, 100 mmol) was added and allowed to stir for 1 h. The CH2Cl2 layer was separated and washed sequentially with NaHCO3 (3 × 50 ml), water (2 × 50 ml), and saturated brine (1 × 50 ml). The organic layer was dried over anhydrous MgSO4, filtered, and concentrated under vacuum to afford a red–yellow solid, which was recrystallized from ethanol (100 ml) to yield a pale-yellow solid (2.42 g, 40%). 1H NMR (500 MHz, CDCl3): δ 7.53–7.20 (m, 6H), 6.56 (m, 1H), 3.35 (m, 2H), 0.23 (s, 9H). 13C NMR (500 MHz, CDCl3): δ 146.0, 139.0, 134.9, 128.7, 128.5, 128.2, 127.7, 127.6, 126.0, 125.3, 102.1, 98.1, 46.1, 0.13.

Synthesis of (E)-1-(1-(3-phenyl­cyclo­penta-2,4-dien-1-yl­idene)eth­yl)pyrrolidine. To a vigorously stirred solution of 1-phenyl-3-tri­methyl­silylethynyl­cyclo­penta­diene (0.336 g, 1.42 mmol) in absolute EtOH (8 ml), pyrrolidine (0.14 ml, 1.70 mmol) was added (Fig. 3[link]). An immediate color change from pale yellow to golden brown was observed. The reaction mixture was allowed to stir at room temperature for 5 h, then to stand for 48 h. During this time, yellow, needle-like crystals of the product fulvene formed, and were isolated by vacuum filtration (0.21 g, 63%). 1H NMR (500 MHz, CDCl3): δ 7.65 (dd, 2H, J1 = 8 Hz, J2 = 1.5 Hz), 7.32 (t, 2H, J = 7.5 Hz), 7.15–7.11 (m, 1H), 3.77 (s, 4H), 2.56 (d, 3H, J = 15 Hz), 2.04 (s, 4H). 13C NMR (500 MHz, CDCl3): δ 156.3, 138.9, 136.2, 133.3, 128.4, 125.3, 121.3, 118.8,115.6, 112.2, 51.9, 25.5, 21.2.

[Figure 3]
Figure 3
Reaction scheme.

Refinement

Crystal data, data collection and structure refinement details are summarized in Table 2[link].

Table 2
Experimental details

Crystal data
Chemical formula C17H19N
Mr 237.33
Crystal system, space group Monoclinic, P21/n
Temperature (K) 100
a, b, c (Å) 6.7724 (13), 7.1774 (14), 26.793 (5)
β (°) 93.184 (3)
V3) 1300.3 (4)
Z 4
Radiation type Mo Kα
μ (mm−1) 0.07
Crystal size (mm) 0.44 × 0.33 × 0.26
 
Data collection
Diffractometer Bruker SMART APEX CCD
Absorption correction Multi-scan (SADABS; Bruker, 2017[Bruker (2017). APEX3 and SAINT. Bruker-Nonius AXS Inc., Madison, Wisconsin, USA.])
Tmin, Tmax 0.82, 0.98
No. of measured, independent and observed [I > 2σ(I)] reflections 14212, 3185, 2252
Rint 0.054
(sin θ/λ)max−1) 0.667
 
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.054, 0.132, 1.03
No. of reflections 3185
No. of parameters 164
H-atom treatment H-atom parameters constrained
Δρmax, Δρmin (e Å−3) 0.30, −0.23
Computer programs: APEX3 (Bruker, 2017[Bruker (2017). APEX3 and SAINT. Bruker-Nonius AXS Inc., Madison, Wisconsin, USA.]), SAINT (Bruker, 2017[Bruker (2017). APEX3 and SAINT. Bruker-Nonius AXS Inc., Madison, Wisconsin, USA.]), SHELXT (Sheldrick, 2015a[Sheldrick, G. M. (2015a). Acta Cryst. A71, 3-8.]), SHELXL2016 (Sheldrick, 2015b[Sheldrick, G. M. (2015b). Acta Cryst. C71, 3-8.]), ORTEP-3 for Windows (Farrugia, 2012[Farrugia, L. J. (2012). J. Appl. Cryst. 45, 849-854.]) and Mercury (Macrae et al., 2008[Macrae, C. F., Bruno, I. J., Chisholm, J. A., Edgington, P. R., McCabe, P., Pidcock, E., Rodriguez-Monge, L., Taylor, R., van de Streek, J. & Wood, P. A. (2008). J. Appl. Cryst. 41, 466-470.]), publCIF (Westrip, 2010[Westrip, S. P. (2010). J. Appl. Cryst. 43, 920-925.]).

Structural data


Computing details top

Data collection: APEX3 (Bruker, 2017); cell refinement: SAINT (Bruker, 2017); data reduction: SAINT (Bruker, 2017); program(s) used to solve structure: SHELXT (Sheldrick, 2015a); program(s) used to refine structure: SHELXL2016 (Sheldrick, 2015b); molecular graphics: ORTEP-3 for Windows (Farrugia, 2012) and Mercury (Macrae et al., 2008); software used to prepare material for publication: publCIF (Westrip, 2010).

(E)-1-[1-(3-Phenylcyclopenta-2,4-dien-1-ylidene)ethyl]pyrrolidine top
Crystal data top
C17H19NF(000) = 512
Mr = 237.33Dx = 1.212 Mg m3
Monoclinic, P21/nMo Kα radiation, λ = 0.71073 Å
a = 6.7724 (13) ÅCell parameters from 2164 reflections
b = 7.1774 (14) Åθ = 2.9–29.9°
c = 26.793 (5) ŵ = 0.07 mm1
β = 93.184 (3)°T = 100 K
V = 1300.3 (4) Å3Needle, translucent yellow
Z = 40.44 × 0.33 × 0.26 mm
Data collection top
Bruker SMART APEX CCD
diffractometer
3185 independent reflections
Radiation source: fine focus sealed tube2252 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.054
Detector resolution: 8.3333 pixels mm-1θmax = 28.3°, θmin = 3.1°
ω scansh = 98
Absorption correction: multi-scan
(SADABS; Bruker, 2017)
k = 99
Tmin = 0.82, Tmax = 0.98l = 3535
14212 measured reflections
Refinement top
Refinement on F20 restraints
Least-squares matrix: fullHydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.054H-atom parameters constrained
wR(F2) = 0.132 w = 1/[σ2(Fo2) + (0.0459P)2 + 0.5603P]
where P = (Fo2 + 2Fc2)/3
S = 1.03(Δ/σ)max = 0.001
3185 reflectionsΔρmax = 0.30 e Å3
164 parametersΔρmin = 0.23 e Å3
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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
N10.61400 (18)0.80353 (18)0.44578 (5)0.0216 (3)
C10.5199 (2)0.6602 (2)0.57666 (6)0.0216 (3)
H10.3821060.6362620.5771950.026*
C20.6539 (2)0.6400 (2)0.61681 (6)0.0227 (3)
C30.8437 (2)0.6917 (2)0.60003 (6)0.0259 (4)
H30.9638880.6913760.6200610.031*
C40.8249 (2)0.7413 (2)0.55085 (6)0.0240 (3)
H40.9292480.7810840.5311060.029*
C50.6195 (2)0.7230 (2)0.53385 (6)0.0204 (3)
C60.5240 (2)0.7603 (2)0.48717 (6)0.0202 (3)
C70.6129 (2)0.5764 (2)0.66719 (6)0.0245 (4)
C80.4256 (3)0.5944 (2)0.68581 (6)0.0286 (4)
H80.3220510.6494770.6654730.034*
C90.3875 (3)0.5334 (3)0.73339 (7)0.0348 (4)
H90.2586140.5462920.7452810.042*
C100.5364 (3)0.4538 (3)0.76354 (7)0.0392 (5)
H100.5107070.4119770.7961890.047*
C110.7229 (3)0.4356 (3)0.74589 (7)0.0361 (4)
H110.8260460.3814450.766570.043*
C120.7609 (3)0.4953 (2)0.69846 (6)0.0303 (4)
H120.8899630.4809980.6868220.036*
C130.3032 (2)0.7549 (2)0.48095 (6)0.0243 (3)
H13A0.2534370.8780640.4707040.036*
H13B0.2485080.7200080.5127460.036*
H13C0.2628810.6629320.4553230.036*
C140.8271 (2)0.7903 (2)0.43937 (6)0.0251 (4)
H14A0.8826330.6756850.4552080.03*
H14B0.8974780.8996980.4541440.03*
C150.8436 (3)0.7848 (3)0.38320 (6)0.0322 (4)
H15A0.8316690.6558110.3703120.039*
H15B0.9708070.8383050.3736020.039*
C160.6702 (3)0.9039 (3)0.36401 (7)0.0349 (4)
H16A0.7033171.0380450.3663760.042*
H16B0.631240.8731650.3288110.042*
C170.5070 (2)0.8549 (2)0.39806 (6)0.0258 (4)
H17A0.4188440.9629310.4026170.031*
H17B0.4271410.7491320.3844470.031*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
N10.0229 (6)0.0207 (7)0.0214 (7)0.0000 (5)0.0025 (5)0.0006 (5)
C10.0233 (7)0.0181 (8)0.0238 (8)0.0006 (6)0.0041 (6)0.0021 (6)
C20.0271 (8)0.0178 (8)0.0232 (8)0.0017 (6)0.0016 (6)0.0025 (6)
C30.0240 (8)0.0272 (9)0.0261 (9)0.0014 (6)0.0015 (6)0.0027 (7)
C40.0207 (7)0.0230 (8)0.0285 (9)0.0001 (6)0.0036 (6)0.0013 (7)
C50.0209 (7)0.0170 (8)0.0233 (8)0.0005 (6)0.0029 (6)0.0007 (6)
C60.0224 (7)0.0152 (7)0.0233 (8)0.0004 (6)0.0040 (6)0.0026 (6)
C70.0341 (9)0.0182 (8)0.0210 (8)0.0008 (6)0.0005 (6)0.0034 (6)
C80.0349 (9)0.0259 (9)0.0250 (9)0.0006 (7)0.0026 (7)0.0000 (7)
C90.0427 (10)0.0352 (10)0.0276 (9)0.0018 (8)0.0107 (8)0.0009 (8)
C100.0590 (12)0.0339 (10)0.0250 (10)0.0008 (9)0.0060 (8)0.0052 (8)
C110.0516 (11)0.0285 (9)0.0276 (10)0.0046 (8)0.0037 (8)0.0039 (7)
C120.0381 (9)0.0240 (9)0.0288 (9)0.0032 (7)0.0003 (7)0.0003 (7)
C130.0217 (7)0.0257 (8)0.0256 (8)0.0009 (6)0.0016 (6)0.0003 (7)
C140.0230 (8)0.0266 (9)0.0262 (9)0.0017 (6)0.0058 (6)0.0009 (7)
C150.0341 (9)0.0346 (10)0.0288 (9)0.0006 (7)0.0106 (7)0.0016 (7)
C160.0421 (10)0.0351 (10)0.0283 (10)0.0065 (8)0.0104 (8)0.0070 (8)
C170.0315 (8)0.0228 (8)0.0232 (9)0.0022 (7)0.0014 (6)0.0004 (6)
Geometric parameters (Å, º) top
N1—C61.331 (2)C10—C111.379 (3)
N1—C141.4658 (19)C10—H100.95
N1—C171.481 (2)C11—C121.379 (2)
C1—C21.376 (2)C11—H110.95
C1—C51.435 (2)C12—H120.95
C1—H10.95C13—H13A0.98
C2—C31.434 (2)C13—H13B0.98
C2—C71.466 (2)C13—H13C0.98
C3—C41.364 (2)C14—C151.516 (2)
C3—H30.95C14—H14A0.99
C4—C51.446 (2)C14—H14B0.99
C4—H40.95C15—C161.519 (2)
C5—C61.402 (2)C15—H15A0.99
C6—C131.496 (2)C15—H15B0.99
C7—C81.395 (2)C16—C171.513 (2)
C7—C121.397 (2)C16—H16A0.99
C8—C91.386 (2)C16—H16B0.99
C8—H80.95C17—H17A0.99
C9—C101.381 (3)C17—H17B0.99
C9—H90.95
C6—N1—C14125.57 (13)C10—C11—H11119.8
C6—N1—C17123.53 (13)C11—C12—C7121.21 (16)
C14—N1—C17110.66 (12)C11—C12—H12119.4
C2—C1—C5109.85 (14)C7—C12—H12119.4
C2—C1—H1125.1C6—C13—H13A109.5
C5—C1—H1125.1C6—C13—H13B109.5
C1—C2—C3106.92 (14)H13A—C13—H13B109.5
C1—C2—C7127.05 (14)C6—C13—H13C109.5
C3—C2—C7126.02 (14)H13A—C13—H13C109.5
C4—C3—C2109.48 (14)H13B—C13—H13C109.5
C4—C3—H3125.3N1—C14—C15104.22 (13)
C2—C3—H3125.3N1—C14—H14A110.9
C3—C4—C5108.49 (14)C15—C14—H14A110.9
C3—C4—H4125.8N1—C14—H14B110.9
C5—C4—H4125.8C15—C14—H14B110.9
C6—C5—C1124.02 (14)H14A—C14—H14B108.9
C6—C5—C4130.70 (14)C14—C15—C16102.90 (14)
C1—C5—C4105.26 (13)C14—C15—H15A111.2
N1—C6—C5125.31 (14)C16—C15—H15A111.2
N1—C6—C13114.48 (13)C14—C15—H15B111.2
C5—C6—C13120.20 (14)C16—C15—H15B111.2
C8—C7—C12117.41 (15)H15A—C15—H15B109.1
C8—C7—C2121.55 (14)C17—C16—C15104.02 (13)
C12—C7—C2121.04 (15)C17—C16—H16A111.0
C9—C8—C7121.30 (16)C15—C16—H16A111.0
C9—C8—H8119.3C17—C16—H16B111.0
C7—C8—H8119.3C15—C16—H16B111.0
C10—C9—C8120.11 (17)H16A—C16—H16B109.0
C10—C9—H9119.9N1—C17—C16103.85 (13)
C8—C9—H9119.9N1—C17—H17A111.0
C11—C10—C9119.47 (17)C16—C17—H17A111.0
C11—C10—H10120.3N1—C17—H17B111.0
C9—C10—H10120.3C16—C17—H17B111.0
C12—C11—C10120.50 (17)H17A—C17—H17B109.0
C12—C11—H11119.8
Hydrogen-bond geometry (Å, º) top
Cg2 and Cg3 are the centroids of the C1–C5 and C7–C12 rings, respectively.
D—H···AD—HH···AD···AD—H···A
C11—H11···Cg3i0.952.753.4505 (7)131
C13—H13C···Cg2ii0.982.703.5435 (7)145
C17—H17A···Cg2iii0.992.673.6104 (7)159
Symmetry codes: (i) x+1/2, y+1/2, z+1/2; (ii) x, y+2, z; (iii) x, y+1, z.
 

Funding information

Funding for this research was provided by: Defense Threat Reduction Agency (DTRA) - Joint Science and Technology Transfer Office for Chemical and Biological Defense ; Air Force Office of Scientific Research (AFOSR) .

References

First citationBruker (2017). APEX3 and SAINT. Bruker–Nonius AXS Inc., Madison, Wisconsin, USA.  Google Scholar
First citationFarrugia, L. J. (2012). J. Appl. Cryst. 45, 849–854.  Web of Science CrossRef CAS IUCr Journals Google Scholar
First citationMacrae, C. F., Bruno, I. J., Chisholm, J. A., Edgington, P. R., McCabe, P., Pidcock, E., Rodriguez-Monge, L., Taylor, R., van de Streek, J. & Wood, P. A. (2008). J. Appl. Cryst. 41, 466–470.  Web of Science CSD CrossRef CAS IUCr Journals Google Scholar
First citationSheldrick, G. M. (2015a). Acta Cryst. A71, 3–8.  Web of Science CrossRef IUCr Journals Google Scholar
First citationSheldrick, G. M. (2015b). Acta Cryst. C71, 3–8.  Web of Science CrossRef IUCr Journals Google Scholar
First citationWestrip, S. P. (2010). J. Appl. Cryst. 43, 920–925.  Web of Science CrossRef CAS IUCr Journals Google Scholar

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