4-[4-(Benz­yloxy)phen­yl]-1,1,1-trifluoro-4-hydroxy­but-3-en-2-one

The mol­ecule of the title compound, C₁₇H₁₃F₃O₃, exists in the enol form and displays a strong intra­molecular O—H...O hydrogen bond. The trifluoro­methyl group is disordered over two orientations in an approximate 2:1 ratio.

Key indicators

• Single-crystal X-ray study
• T = 294 K
• Mean [sigma](C-C) = 0.006 Å
• Disorder in main residue
• R factor = 0.057
• wR factor = 0.152
• Data-to-parameter ratio = 7.9

checkCIF/PLATON results

No syntax errors found



Alert level B
PLAT242_ALERT_2_B Check Low       Ueq as Compared to Neighbors for        C17
PLAT431_ALERT_2_B Short Inter HL..A Contact  F1'    ..  F2'     ..       2.52 Ang.

Alert level C
PLAT089_ALERT_3_C Poor Data / Parameter Ratio (Zmax .LT. 18) .....       7.87
PLAT301_ALERT_3_C Main Residue  Disorder .........................      12.00 Perc.
PLAT340_ALERT_3_C Low Bond Precision on C-C Bonds (x 1000) Ang ...          6

Alert level G
REFLT03_ALERT_4_G Please check that the estimate of the number of Friedel pairs is
            correct. If it is not, please give the correct count in the
            _publ_section_exptl_refinement section of the submitted CIF.
           From the CIF: _diffrn_reflns_theta_max           27.00
           From the CIF: _reflns_number_total               1881
           Count of symmetry unique reflns         1895
           Completeness (_total/calc)             99.26%
           TEST3: Check Friedels for noncentro structure
           Estimate of Friedel pairs measured         0
           Fraction of Friedel pairs measured     0.000
           Are heavy atom types Z>Si present         no
PLAT860_ALERT_3_G Note: Number of Least-Squares Restraints .......         66

   0 ALERT level A = In general: serious problem
   2 ALERT level B = Potentially serious problem
   3 ALERT level C = Check and explain
   2 ALERT level G = General alerts; check

   0 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   2 ALERT type 2 Indicator that the structure model may be wrong or deficient
   4 ALERT type 3 Indicator that the structure quality may be low
   1 ALERT type 4 Improvement, methodology, query or suggestion
   0 ALERT type 5 Informative message, check

---

S1. Comment

1,3-Diketones are important intermediates not only as a key building block for the synthesis of core heterocycles in medicinal chemistry (Rowley et al., 1996) but also as an invaluable chelating ligand for various lanthanide and transition metals in material chemistry (Shavaleev et al., 2003). The molecular structure of the title compound, (I), exists in the enolized form and displays a strong intramolecular hydrogen bond (Fig. 1 and Table 2). The geometric data (Table 1) are in agreement with reported literature values (Gilli et al., 2004; Wang et al., 2006). The CF₃ group is disordered.

Related literature

For general background, see: Rowley et al. (1996); Shavaleev et al. (2003). For related structures, see: Gilli et al. (2004); Wang et al. (2006).

S2. Experimental

The mixture of 1-[4-(benzyloxy)phenyl]ethanone (9.10 g, 0.04 mol), ethyl trifluoracetate (10 ml, 0.084 mol), CH₃ONa (4.32 g, 0.08 mol) and benzene (150 ml) was stirred at 323 K for 8 h. The reaction mixture was cooled to room temperature, acidified with dilute hydrochloric acid and then stirred until all solids dissolved. The benzene layer was separated, washed with a saturated NaHCO₃ solution, dried over anhydrous Mg₂SO₄ and the solvent was removed by evaporation. The residual oil solidified on standing and the solid was recrystallized from ethanol to give the title compound (yield 10.10 g, 78.4%; m.p. 367 K). Single crystals suitable for X-ray diffraction were grown by slow evaporation of an ethanol solution at room temperature. Spectroscopic analysis, ¹H NMR (CDCl₃, 400 MHz, δ p.p.m.): 5.16 (s, 2H, –CH₂O–), 6.51 (s, 1H, enol CH), 7.07 (d, J=8.8 Hz, 2H, Ar—H), 7.40–7.43 (m, 5H, Ar—H), 7.94 (d, J=9.2 Hz, 2H, Ar—H), 15.41 (brs, 1H, enol OH); IR (KBr, ν cm^-1): 1600 (C═O), 1508 (C═C), 2930 (C—H, alkyl).

S3. Refinement

The CF₃ group was found to be disordered over two orientations. The occupancies of the disordered positions of F1/F1', F2/F2' and F3/F3' were refined to 0.641 (11) /0.359 (11). Similarity restraints with standard uncertainty of 0.01 were applied for C—F and F···F distances and the displacement parameters of the F atoms were restrained to isotopic behavior. The H atom of the hydroxyl group was located in a difference Fourier map and its position was refined freely, with U_iso(H) = 1.5 U_eq(O). Other H atoms were refined as riding, with C—H = 0.93 to 0.97 Å, and with U_iso(H) = 1.2 (1.5 for methyl) U_eq(C). In the absence of significant anomalous scattering effects Friedel pairs have been merged.

Computing details

Data collection: SMART (Bruker, 1997); cell refinement: SAINT (Bruker, 1999); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: SHELXTL (Bruker, 2001); software used to prepare material for publication: SHELXTL.

Figures

Fig. 1. The molecular structure of (I), showing the atom-labeling scheme. Displacement ellipsoids of non-H atoms are drawn at the 30% probability level. Only one component of the disordered CF3 group is shown.

4-[4-(Benzyloxy)phenyl]-1,1,1-trifluoro-4-hydroxybut-3-en-2-one

Crystal data

C17H13F3O3	F(000) = 664
Mr = 322.27	Dx = 1.429 Mg m^−3
Orthorhombic, P212121	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: P 2ac 2ab	Cell parameters from 923 reflections
a = 7.6226 (11) Å	θ = 2.3–19.1°
b = 11.0708 (15) Å	µ = 0.12 mm^−1
c = 17.748 (2) Å	T = 294 K
V = 1497.7 (3) Å^3	Block, colorless
Z = 4	0.20 × 0.10 × 0.10 mm

Data collection

Bruker APEX CCD area-detector diffractometer	1881 independent reflections
Radiation source: fine-focus sealed tube	1110 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.044
φ and ω scans	θmax = 27.0°, θmin = 2.2°
Absorption correction: multi-scan (SADABS; Sheldrick, 2001)	h = −9→9
Tmin = 0.976, Tmax = 0.983	k = −14→12
6737 measured reflections	l = −16→22

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.057	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.152	H atoms treated by a mixture of independent and constrained refinement
S = 1.06	w = 1/[σ^2(Fo^2) + (0.0746P)^2] where P = (Fo^2 + 2Fc^2)/3
1881 reflections	(Δ/σ)max < 0.001
239 parameters	Δρmax = 0.16 e Å^−3
66 restraints	Δρmin = −0.19 e Å^−3

Special details

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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq	Occ. (<1)
C1	0.3740 (6)	0.8855 (4)	−0.1935 (2)	0.0626 (12)
C2	0.3147 (6)	0.7911 (4)	−0.2368 (3)	0.0690 (12)
H2	0.2789	0.7200	−0.2136	0.083*
C3	0.3078 (7)	0.8003 (5)	−0.3137 (3)	0.0787 (14)
H3	0.2660	0.7360	−0.3422	0.094*
C4	0.3626 (7)	0.9049 (5)	−0.3489 (3)	0.0815 (15)
H4	0.3585	0.9109	−0.4011	0.098*
C5	0.4231 (7)	1.0001 (5)	−0.3067 (3)	0.0835 (15)
H5	0.4582	1.0711	−0.3302	0.100*
C6	0.4317 (6)	0.9904 (4)	−0.2297 (3)	0.0714 (12)
H6	0.4762	1.0541	−0.2014	0.086*
C7	0.3784 (7)	0.8811 (4)	−0.1086 (2)	0.0668 (12)
H7A	0.4802	0.9245	−0.0901	0.080*
H7B	0.2741	0.9192	−0.0882	0.080*
C8	0.3801 (6)	0.7331 (4)	−0.0104 (2)	0.0612 (11)
C9	0.3715 (7)	0.6124 (4)	0.0080 (3)	0.0793 (14)
H9	0.3680	0.5548	−0.0301	0.095*
C10	0.3680 (7)	0.5765 (4)	0.0812 (2)	0.0742 (14)
H10	0.3623	0.4945	0.0924	0.089*
C11	0.3728 (6)	0.6596 (3)	0.1395 (2)	0.0561 (10)
C12	0.3821 (7)	0.7810 (4)	0.1203 (2)	0.0683 (13)
H12	0.3847	0.8387	0.1584	0.082*
C13	0.3876 (6)	0.8183 (4)	0.0466 (2)	0.0691 (13)
H13	0.3962	0.9000	0.0350	0.083*
C14	0.3696 (5)	0.6193 (4)	0.2183 (2)	0.0620 (11)
C15	0.3426 (6)	0.6954 (4)	0.2797 (2)	0.0626 (11)
H15	0.3231	0.7773	0.2719	0.075*
C16	0.3446 (6)	0.6505 (4)	0.3516 (3)	0.0678 (13)
C17	0.3182 (7)	0.7320 (5)	0.4185 (3)	0.0852 (16)
F1	0.2753 (14)	0.6788 (5)	0.4809 (3)	0.122 (3)	0.641 (11)
F2	0.1903 (12)	0.8142 (7)	0.4089 (3)	0.122 (3)	0.641 (11)
F3	0.4573 (10)	0.7974 (9)	0.4330 (5)	0.141 (4)	0.641 (11)
F1'	0.436 (2)	0.6954 (13)	0.4677 (8)	0.151 (6)	0.359 (11)
F2'	0.1678 (14)	0.7131 (15)	0.4486 (9)	0.142 (6)	0.359 (11)
F3'	0.343 (3)	0.8437 (7)	0.4061 (7)	0.120 (5)	0.359 (11)
O1	0.3861 (5)	0.7590 (2)	−0.08524 (15)	0.0738 (10)
O2	0.3947 (5)	0.5056 (3)	0.2297 (2)	0.0887 (11)
O3	0.3710 (6)	0.5400 (3)	0.3683 (2)	0.0963 (12)
H1	0.370 (9)	0.503 (5)	0.300 (4)	0.144*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
C1	0.063 (3)	0.068 (3)	0.057 (3)	0.008 (3)	0.003 (2)	0.002 (2)
C2	0.072 (3)	0.067 (3)	0.068 (3)	0.000 (2)	−0.006 (2)	0.002 (2)
C3	0.088 (4)	0.076 (3)	0.072 (3)	−0.002 (3)	−0.009 (3)	−0.005 (3)
C4	0.084 (4)	0.097 (4)	0.063 (3)	0.006 (3)	−0.007 (3)	0.010 (3)
C5	0.095 (4)	0.084 (3)	0.071 (3)	0.006 (3)	0.007 (3)	0.020 (3)
C6	0.082 (3)	0.061 (3)	0.071 (3)	−0.002 (2)	0.006 (3)	0.003 (2)
C7	0.079 (3)	0.060 (3)	0.062 (3)	−0.001 (3)	−0.002 (3)	−0.003 (2)
C8	0.065 (3)	0.058 (2)	0.061 (3)	0.004 (2)	0.004 (2)	0.001 (2)
C9	0.110 (4)	0.060 (3)	0.068 (3)	−0.006 (3)	0.007 (3)	−0.010 (2)
C10	0.101 (4)	0.050 (2)	0.072 (3)	0.005 (3)	0.008 (3)	−0.003 (2)
C11	0.057 (3)	0.055 (2)	0.056 (2)	0.003 (2)	0.001 (2)	−0.0025 (19)
C12	0.094 (4)	0.055 (3)	0.056 (3)	−0.007 (3)	0.004 (3)	−0.004 (2)
C13	0.087 (3)	0.052 (2)	0.069 (3)	−0.004 (3)	−0.002 (3)	−0.001 (2)
C14	0.057 (3)	0.053 (2)	0.076 (3)	0.006 (2)	0.005 (3)	0.011 (2)
C15	0.074 (3)	0.056 (2)	0.058 (3)	−0.005 (2)	0.004 (2)	0.004 (2)
C16	0.069 (3)	0.068 (3)	0.066 (3)	−0.006 (2)	−0.003 (3)	0.015 (2)
C17	0.104 (5)	0.088 (4)	0.064 (3)	−0.011 (4)	−0.017 (3)	0.012 (3)
F1	0.186 (8)	0.106 (4)	0.075 (4)	0.007 (5)	0.043 (4)	0.026 (3)
F2	0.171 (7)	0.117 (5)	0.079 (4)	0.047 (5)	−0.025 (4)	−0.024 (3)
F3	0.130 (6)	0.153 (7)	0.141 (6)	−0.061 (5)	0.021 (5)	−0.054 (5)
F1'	0.172 (10)	0.180 (11)	0.100 (8)	−0.008 (9)	−0.064 (7)	−0.014 (7)
F2'	0.120 (8)	0.173 (11)	0.134 (10)	−0.023 (8)	0.035 (7)	−0.046 (8)
F3'	0.160 (11)	0.091 (7)	0.111 (7)	−0.017 (7)	0.001 (8)	−0.003 (5)
O1	0.107 (3)	0.0595 (18)	0.0547 (18)	0.0060 (19)	0.0085 (18)	0.0011 (14)
O2	0.122 (3)	0.060 (2)	0.084 (2)	0.011 (2)	0.020 (2)	0.0129 (16)
O3	0.126 (3)	0.086 (2)	0.077 (2)	0.016 (2)	0.012 (2)	0.0271 (19)

Geometric parameters (Å, º)

C1—C2	1.373 (6)	C10—H10	0.9300
C1—C6	1.398 (6)	C11—C12	1.389 (6)
C1—C7	1.508 (6)	C11—C14	1.467 (6)
C2—C3	1.369 (6)	C12—C13	1.373 (6)
C2—H2	0.9300	C12—H12	0.9300
C3—C4	1.380 (7)	C13—H13	0.9300
C3—H3	0.9300	C14—O2	1.289 (5)
C4—C5	1.372 (7)	C14—C15	1.394 (6)
C4—H4	0.9300	C15—C16	1.369 (6)
C5—C6	1.372 (6)	C15—H15	0.9300
C5—H5	0.9300	C16—O3	1.274 (5)
C6—H6	0.9300	C16—C17	1.505 (7)
C7—O1	1.415 (5)	C17—F3'	1.270 (7)
C7—H7A	0.9700	C17—F2'	1.282 (7)
C7—H7B	0.9700	C17—F1	1.296 (6)
C8—O1	1.360 (5)	C17—F3	1.309 (6)
C8—C9	1.377 (6)	C17—F1'	1.318 (7)
C8—C13	1.384 (6)	C17—F2	1.344 (6)
C9—C10	1.359 (6)	O2—H1	1.26 (6)
C9—H9	0.9300	O3—H1	1.29 (6)
C10—C11	1.385 (6)
C2—C1—C6	118.6 (4)	C10—C11—C14	120.6 (4)
C2—C1—C7	122.8 (4)	C12—C11—C14	122.0 (4)
C6—C1—C7	118.6 (4)	C13—C12—C11	121.8 (4)
C3—C2—C1	120.9 (4)	C13—C12—H12	119.1
C3—C2—H2	119.5	C11—C12—H12	119.1
C1—C2—H2	119.5	C12—C13—C8	119.4 (4)
C2—C3—C4	120.1 (5)	C12—C13—H13	120.3
C2—C3—H3	119.9	C8—C13—H13	120.3
C4—C3—H3	119.9	O2—C14—C15	119.3 (4)
C5—C4—C3	119.9 (5)	O2—C14—C11	116.4 (4)
C5—C4—H4	120.0	C15—C14—C11	124.3 (4)
C3—C4—H4	120.0	C16—C15—C14	120.5 (4)
C6—C5—C4	120.0 (5)	C16—C15—H15	119.7
C6—C5—H5	120.0	C14—C15—H15	119.7
C4—C5—H5	120.0	O3—C16—C15	124.5 (5)
C5—C6—C1	120.5 (5)	O3—C16—C17	114.4 (4)
C5—C6—H6	119.8	C15—C16—C17	121.0 (4)
C1—C6—H6	119.8	F3'—C17—F2'	111.4 (7)
O1—C7—C1	108.9 (3)	F1—C17—F3	106.7 (5)
O1—C7—H7A	109.9	F3'—C17—F1'	108.3 (7)
C1—C7—H7A	109.9	F2'—C17—F1'	106.4 (7)
O1—C7—H7B	109.9	F1—C17—F2	103.5 (5)
C1—C7—H7B	109.9	F3—C17—F2	103.8 (5)
H7A—C7—H7B	108.3	F3'—C17—C16	115.4 (7)
O1—C8—C9	116.0 (4)	F2'—C17—C16	110.5 (7)
O1—C8—C13	124.6 (4)	F1—C17—C16	115.8 (5)
C9—C8—C13	119.4 (4)	F3—C17—C16	112.2 (5)
C10—C9—C8	120.8 (4)	F1'—C17—C16	104.3 (7)
C10—C9—H9	119.6	F2—C17—C16	113.8 (4)
C8—C9—H9	119.6	C8—O1—C7	119.1 (3)
C9—C10—C11	121.3 (4)	C14—O2—H1	99 (3)
C9—C10—H10	119.4	C16—O3—H1	95 (3)
C11—C10—H10	119.4	C16—O3—H1	95 (3)
C10—C11—C12	117.4 (4)
C6—C1—C2—C3	−1.7 (7)	C12—C11—C14—C15	12.5 (7)
C7—C1—C2—C3	177.9 (5)	O2—C14—C15—C16	0.7 (7)
C1—C2—C3—C4	0.8 (8)	C11—C14—C15—C16	−178.9 (4)
C2—C3—C4—C5	−0.4 (8)	C14—C15—C16—O3	0.3 (8)
C3—C4—C5—C6	1.1 (8)	C14—C15—C16—C17	179.1 (4)
C4—C5—C6—C1	−2.0 (8)	O3—C16—C17—F3'	160.2 (10)
C2—C1—C6—C5	2.3 (7)	C15—C16—C17—F3'	−18.7 (11)
C7—C1—C6—C5	−177.3 (5)	O3—C16—C17—F2'	−72.4 (11)
C2—C1—C7—O1	24.2 (7)	C15—C16—C17—F2'	108.7 (11)
C6—C1—C7—O1	−156.2 (4)	O3—C16—C17—F1	−19.0 (8)
O1—C8—C9—C10	178.8 (4)	C15—C16—C17—F1	162.1 (7)
C13—C8—C9—C10	0.8 (9)	O3—C16—C17—F3	103.8 (8)
C8—C9—C10—C11	0.1 (9)	C15—C16—C17—F3	−75.2 (8)
C9—C10—C11—C12	−0.3 (8)	O3—C16—C17—F1'	41.6 (11)
C9—C10—C11—C14	−179.8 (5)	C15—C16—C17—F1'	−137.3 (10)
C10—C11—C12—C13	−0.4 (8)	O3—C16—C17—F2	−138.7 (7)
C14—C11—C12—C13	179.1 (4)	C15—C16—C17—F2	42.3 (8)
C11—C12—C13—C8	1.3 (8)	C9—C8—O1—C7	174.1 (4)
O1—C8—C13—C12	−179.3 (4)	C13—C8—O1—C7	−8.0 (8)
C9—C8—C13—C12	−1.5 (8)	C1—C7—O1—C8	−175.9 (4)
C10—C11—C14—O2	12.3 (7)	C15—C16—O3—H1	−7 (3)
C12—C11—C14—O2	−167.1 (5)	C17—C16—O3—H1	174 (3)
C10—C11—C14—C15	−168.0 (5)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O2—H1···O3	1.26 (6)	1.29 (6)	2.496 (5)	158 (5)