(S)-4-Benzyl-3-[(R)-4,4,4-tri­fluoro-3-(4-methoxy­phenyl)­butanoyl]-1,3-oxazolidin-2-one

The C atom at the chiral centre of the title compound, C₂₁H₂₀F₃NO₄, takes an R configuration. From this assignment, useful information on the intermediate process of the reaction was deduced.

S1. Comment

The title compound, (I), was prepared by way of Michael addition of an organocopper species to 3-[(E)-4,4,4-trifluorobut-2-enoyl]oxazolidin-2-ones in order to obtain optically active molecules with a CF₃ moiety at the chiral centre. The structure determination was made so as to clarify how the molecule is built up through the synthetic reaction. The C atom at the chiral centre takes R configuration. From this establishment, a useful information on the intermediate process of the reaction was deduced: the construction of the molecule possibly proceeded via intramolecular bidentate chelation between Cu atom and carbonyl groups, rather than a conformation which without such chelation reduces the dipolar repulsion between the carbonyl groups and results in S configuration of the chiral atom owing to stereoselectivity (Yamazaki et al., 1999). The configuration of the asymmetric carbon atom in the five-membered ring is S. The C—F bond lengths are 1.330 (6) Å on average. The CF₃ and CH₃ groups as well as the benzene-ring part show large atomic displacement parameters. \scheme

S2. Experimental

The preparation of the title compound was presented in a report by Yamazaki et al. (1999). Single crystals were grown by slow evaporation from a mixture of hexane and ethyl acetate.

S3. Refinement

No Friedel pairs were measured. All H atoms were located in difference maps. Only their U_iso were refined, but some of these were fixed.

Computing details

Data collection: MSC/AFC Diffractometer Control (Rigaku, 1991); cell refinement: MSC/AFC Diffractometer Control; data reduction: TEXSAN (Molecular Structure Corporation, 1998); program(s) used to solve structure: MULTAN88 (Debaedemaeker et al., 1985); program(s) used to refine structure: TEXSAN; molecular graphics: ORTEP-II (Johnson, 1976); software used to prepare material for publication: TEXSAN.

(I)

Crystal data

C21H20F3NO4	Dx = 1.329 Mg m^−3
Mr = 407.39	Mo Kα radiation, λ = 0.7107 Å
Orthorhombic, P212121	Cell parameters from 25 reflections
a = 13.115 (3) Å	θ = 14.6–17.2°
b = 24.305 (3) Å	µ = 0.11 mm^−1
c = 6.388 (3) Å	T = 298 K
V = 2036.2 (11) Å^3	Plate, colourless
Z = 4	0.70 × 0.50 × 0.30 mm

Data collection

Rigaku AFC-5R diffractometer	Rint = 0.017
ω–2θ scans	θmax = 27.5°
Absorption correction: ψ scan (North et al., 1968)	h = 0→17
Tmin = 0.865, Tmax = 0.999	k = 0→31
2716 measured reflections	l = 0→8
2641 independent reflections	4 standard reflections every 150 reflections
1619 reflections with F^2 > 2σ(F^2)	intensity decay: 0.3%

Refinement

Refinement on F^2	w = 1/[σ^2(Fo^2) + 0.00160(Fo^2)^2]
R[F^2 > 2σ(F^2)] = 0.048	(Δ/σ)max = 0.0002
wR(F^2) = 0.137	Δρmax = 0.15 e Å^−3
S = 2.00	Δρmin = −0.12 e Å^−3
2689 reflections	Extinction correction: Zachariasen (1967), type 2, Gaussian isotropic
275 parameters	Extinction coefficient: 0.007 (2)
Only H-atom displacement parameters refined	Absolute structure: From the configuration of C14 in the starting material.

Special details

Refinement. Refinement using reflections with F² > −10.0 σ(F²). The weighted R-factor (wR) and goodness of fit (S) are based on F². R-factor (gt) is based on F. The threshold expression of F² > 2.0 σ(F²) is used only for calculating R-factor (gt).

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

	x	y	z	Uiso*/Ueq
F1	0.5820 (2)	0.4382 (1)	−0.0826 (5)	0.119 (1)
F2	0.5398 (3)	0.50701 (10)	0.1035 (7)	0.141 (1)
F3	0.6764 (2)	0.4617 (1)	0.1701 (7)	0.147 (1)
O1	0.0955 (2)	0.4271 (1)	0.1082 (6)	0.0943 (10)
O2	0.5027 (2)	0.3542 (1)	0.6123 (4)	0.0917 (9)
O3	0.6361 (2)	0.2553 (1)	0.1562 (4)	0.0825 (8)
O4	0.6372 (2)	0.1957 (1)	0.4195 (4)	0.0888 (9)
N1	0.5662 (2)	0.2763 (1)	0.4795 (4)	0.0610 (7)
C1	0.0548 (4)	0.4043 (3)	−0.074 (1)	0.124 (2)
C2	0.1990 (3)	0.4238 (1)	0.1358 (7)	0.074 (1)
C3	0.2383 (3)	0.4471 (1)	0.3165 (7)	0.079 (1)
C4	0.3408 (3)	0.4452 (1)	0.3562 (6)	0.075 (1)
C5	0.4075 (3)	0.4204 (1)	0.2182 (6)	0.0666 (10)
C6	0.3677 (3)	0.3978 (1)	0.0384 (6)	0.078 (1)
C7	0.2644 (3)	0.3988 (2)	−0.0035 (7)	0.081 (1)
C8	0.5214 (3)	0.4199 (1)	0.2639 (6)	0.077 (1)
C9	0.5790 (4)	0.4561 (2)	0.111 (1)	0.101 (2)
C10	0.5673 (3)	0.3619 (2)	0.2640 (6)	0.071 (1)
C11	0.5418 (2)	0.3321 (1)	0.4623 (5)	0.0639 (9)
C12	0.6155 (3)	0.2442 (2)	0.3326 (6)	0.0659 (10)
C13	0.6071 (3)	0.1939 (2)	0.6363 (6)	0.087 (1)
C14	0.5476 (3)	0.2469 (2)	0.6752 (5)	0.078 (1)
C15	0.4339 (3)	0.2365 (2)	0.7193 (6)	0.085 (1)
C16	0.3780 (2)	0.2053 (2)	0.5523 (6)	0.073 (1)
C17	0.3464 (2)	0.2324 (2)	0.3743 (7)	0.088 (1)
C18	0.2966 (3)	0.2048 (4)	0.2160 (7)	0.129 (2)
C19	0.2783 (4)	0.1495 (5)	0.236 (1)	0.149 (3)
C20	0.3096 (4)	0.1211 (3)	0.409 (2)	0.137 (3)
C21	0.3587 (3)	0.1494 (2)	0.571 (1)	0.111 (2)
H1a	0.0569	0.3623	−0.1217	0.1469*
H1b	0.0020	0.4167	−0.0983	0.1469*
H1c	0.0966	0.4213	−0.1815	0.1469*
H3	0.1965	0.4657	0.4357	0.11 (1)*
H4	0.3792	0.4607	0.4941	0.13 (1)*
H6	0.4156	0.3829	−0.0596	0.11 (1)*
H7	0.2384	0.3826	−0.1284	0.11 (1)*
H8	0.5227	0.4356	0.4050	0.065 (9)*
H10a	0.5656	0.3452	0.1470	0.064 (9)*
H10b	0.6481	0.3634	0.2505	0.08 (1)*
H13a	0.6670	0.1942	0.6961	0.09 (1)*
H13b	0.5517	0.1542	0.6558	0.10 (1)*
H14	0.5771	0.2597	0.8009	0.10 (1)*
H15a	0.4291	0.2166	0.8459	0.11 (1)*
H15b	0.4020	0.2715	0.7349	0.11 (1)*
H17	0.3580	0.2713	0.3611	0.1051*
H18	0.2747	0.2222	0.0916	0.1629*
H19	0.2436	0.1276	0.1333	0.1900*
H20	0.2991	0.0814	0.4275	0.1637*
H21	0.3816	0.1300	0.6976	0.1350*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
F1	0.142 (2)	0.093 (2)	0.122 (2)	−0.008 (2)	0.053 (2)	0.004 (2)
F2	0.156 (2)	0.061 (1)	0.206 (3)	−0.005 (1)	0.059 (2)	0.000 (2)
F3	0.106 (2)	0.124 (2)	0.210 (4)	−0.042 (2)	0.027 (2)	0.001 (3)
O1	0.084 (2)	0.085 (2)	0.115 (2)	0.005 (1)	0.001 (2)	0.013 (2)
O2	0.108 (2)	0.102 (2)	0.065 (2)	0.005 (2)	0.021 (2)	−0.024 (1)
O3	0.110 (2)	0.087 (2)	0.050 (1)	0.022 (1)	0.013 (1)	−0.001 (1)
O4	0.102 (2)	0.091 (2)	0.074 (2)	0.027 (1)	0.004 (1)	0.018 (1)
N1	0.059 (1)	0.082 (2)	0.042 (1)	0.005 (1)	−0.001 (1)	−0.003 (1)
C1	0.115 (4)	0.129 (4)	0.128 (5)	−0.008 (3)	−0.022 (4)	0.018 (4)
C2	0.084 (2)	0.052 (2)	0.087 (3)	0.004 (2)	0.012 (2)	0.012 (2)
C3	0.092 (3)	0.064 (2)	0.082 (3)	0.008 (2)	0.022 (2)	−0.010 (2)
C4	0.084 (2)	0.063 (2)	0.078 (2)	0.001 (2)	0.018 (2)	−0.016 (2)
C5	0.080 (2)	0.047 (2)	0.073 (2)	−0.002 (1)	0.017 (2)	−0.007 (2)
C6	0.096 (3)	0.068 (2)	0.071 (2)	0.006 (2)	0.021 (2)	−0.011 (2)
C7	0.095 (3)	0.074 (2)	0.073 (2)	0.002 (2)	0.009 (2)	−0.002 (2)
C8	0.085 (2)	0.066 (2)	0.081 (2)	−0.008 (2)	0.020 (2)	−0.022 (2)
C9	0.099 (3)	0.063 (2)	0.143 (5)	−0.012 (2)	0.022 (3)	−0.010 (3)
C10	0.075 (2)	0.076 (2)	0.063 (2)	−0.001 (2)	0.012 (2)	−0.014 (2)
C11	0.058 (2)	0.080 (2)	0.054 (2)	−0.004 (2)	0.005 (2)	−0.016 (2)
C12	0.072 (2)	0.076 (2)	0.050 (2)	0.011 (2)	−0.005 (2)	−0.002 (2)
C13	0.069 (2)	0.124 (3)	0.068 (2)	0.007 (2)	−0.008 (2)	0.030 (2)
C14	0.072 (2)	0.117 (3)	0.043 (2)	0.001 (2)	−0.004 (2)	0.009 (2)
C15	0.079 (2)	0.123 (3)	0.053 (2)	−0.006 (2)	0.012 (2)	0.007 (2)
C16	0.055 (2)	0.102 (3)	0.062 (2)	0.008 (2)	0.010 (2)	0.003 (2)
C17	0.046 (2)	0.139 (4)	0.079 (3)	0.003 (2)	0.003 (2)	0.008 (3)
C18	0.049 (2)	0.266 (9)	0.072 (3)	−0.002 (3)	0.000 (2)	−0.012 (4)
C19	0.062 (3)	0.230 (9)	0.154 (7)	−0.008 (4)	0.008 (4)	−0.090 (7)
C20	0.076 (3)	0.127 (5)	0.207 (8)	−0.008 (3)	0.011 (4)	−0.052 (5)
C21	0.073 (2)	0.107 (4)	0.151 (5)	0.000 (2)	0.007 (3)	0.009 (4)

Geometric parameters (Å, º)

F1—C9	1.310 (6)	C8—C9	1.518 (6)
F2—C9	1.340 (5)	C8—C10	1.531 (5)
F3—C9	1.339 (6)	C8—H8	0.98)
O1—C1	1.392 (7)	C10—C11	1.498 (5)
O1—C2	1.372 (5)	C10—H10a	0.85
O2—C11	1.213 (4)	C10—H10b	1.06
O3—C12	1.190 (4)	C13—C14	1.526 (6)
O4—C12	1.334 (4)	C13—H13a	0.87
O4—C13	1.441 (5)	C13—H13b	1.21
N1—C11	1.397 (4)	C14—C15	1.539 (5)
N1—C12	1.380 (4)	C14—H14	0.94
N1—C14	1.460 (4)	C15—C16	1.499 (6)
C1—H1a	1.07	C15—H15a	0.94
C1—H1b	0.77	C15—H15b	0.95
C1—H1c	0.97	C16—C17	1.378 (6)
C2—C3	1.384 (6)	C16—C21	1.388 (6)
C2—C7	1.377 (6)	C17—C18	1.378 (8)
C3—C4	1.368 (5)	C17—H17	0.96
C3—H3	1.04	C18—C19	1.37 (1)
C4—C5	1.380 (5)	C18—H18	0.94
C4—H4	1.08	C19—C20	1.36 (1)
C5—C6	1.377 (5)	C19—H19	0.96)
C5—C8	1.523 (5)	C20—C21	1.403 (9)
C6—C7	1.382 (6)	C20—H20	0.98
C6—H6	0.96	C21—H21	0.98
C7—H7	0.95
F1···O2^i	3.008 (4)	O3···C14^i	3.290 (4)
F1···C19^ii	3.483 (8)	O3···C18^ii	3.321 (6)
F2···C1^iii	3.231 (7)	O4···C1^ii	3.459 (8)
F2···C20^iv	3.406 (7)	O4···C17^viii	3.509 (5)
O1···C13^v	3.367 (5)	C2···C13^v	3.429 (6)
O1···C4^vi	3.595 (5)	C14···C18^viii	3.539 (6)
O2···C6^vii	3.415 (4)
C1—O1—C2	117.6 (4)	C11—C10—H10b	107.9 (3)
C12—O4—C13	111.6 (3)	H10a—C10—H10b	88.4 (3)
C11—N1—C12	127.0 (3)	O2—C11—N1	117.7 (3)
C11—N1—C14	120.3 (3)	O2—C11—C10	123.2 (3)
C12—N1—C14	112.6 (3)	N1—C11—C10	119.0 (3)
O1—C1—H1a	127.6 (5)	O3—C12—O4	123.0 (3)
O1—C1—H1b	111.1 (7)	O3—C12—N1	128.6 (3)
O1—C1—H1c	101.9 (5)	O4—C12—N1	108.4 (3)
H1a—C1—H1b	109.7 (6)	O4—C13—C14	105.7 (3)
H1a—C1—H1c	100.8 (6)	O4—C13—H13a	100.0 (4)
H1b—C1—H1c	101.3 (6)	O4—C13—H13b	106.7 (4)
O1—C2—C3	116.8 (4)	C14—C13—H13a	112.4 (5)
O1—C2—C7	124.0 (4)	C14—C13—H13b	110.3 (3)
C3—C2—C7	119.2 (4)	H13a—C13—H13b	120.0 (4)
C2—C3—C4	120.4 (3)	N1—C14—C13	100.8 (3)
C2—C3—H3	126.2 (4)	N1—C14—C15	113.5 (3)
C4—C3—H3	113.3 (4)	N1—C14—H14	119.8 (4)
C3—C4—C5	121.2 (4)	C13—C14—C15	112.7 (4)
C3—C4—H4	126.7 (4)	C13—C14—H14	102.0 (3)
C5—C4—H4	112.1 (3)	C15—C14—H14	107.2 (3)
C4—C5—C6	117.9 (3)	C14—C15—C16	115.3 (3)
C4—C5—C8	120.2 (3)	C14—C15—H15a	107.8 (3)
C6—C5—C8	121.9 (3)	C14—C15—H15b	107.3 (4)
C5—C6—C7	121.7 (3)	C16—C15—H15a	108.6 (4)
C5—C6—H6	116.6 (4)	C16—C15—H15b	108.0 (3)
C7—C6—H6	121.6 (4)	H15a—C15—H15b	109.7 (4)
C2—C7—C6	119.6 (4)	C15—C16—C17	119.6 (4)
C2—C7—H7	120.1 (4)	C15—C16—C21	121.4 (4)
C6—C7—H7	120.3 (4)	C17—C16—C21	119.0 (4)
C5—C8—C9	111.1 (4)	C16—C17—C18	121.0 (5)
C5—C8—C10	113.2 (3)	C16—C17—H17	119.6 (4)
C5—C8—H8	100.9 (3)	C18—C17—H17	119.4 (5)
C9—C8—C10	109.8 (3)	C17—C18—C19	119.5 (6)
C9—C8—H8	111.0 (4)	C17—C18—H18	122.8 (9)
C10—C8—H8	110.6 (4)	C19—C18—H18	117.7 (8)
F1—C9—F2	106.6 (5)	C18—C19—C20	121.2 (6)
F1—C9—F3	105.8 (5)	C18—C19—H19	124 (1)
F1—C9—C8	115.5 (4)	C20—C19—H19	114 (1)
F2—C9—F3	106.4 (4)	C19—C20—C21	119.3 (6)
F2—C9—C8	111.5 (4)	C19—C20—H20	123.7 (9)
F3—C9—C8	110.5 (5)	C21—C20—H20	117.1 (9)
C8—C10—C11	111.0 (3)	C16—C21—C20	119.9 (6)
C8—C10—H10a	115.4 (4)	C16—C21—H21	119.1 (6)
C8—C10—H10b	111.1 (3)	C20—C21—H21	120.9 (6)
C11—C10—H10a	120.3 (4)
F1—C9—C8—C5	−69.0 (5)	C4—C3—C2—C7	0.0 (5)
F1—C9—C8—C10	57.0 (6)	C4—C5—C6—C7	−0.9 (5)
F2—C9—C8—C5	52.9 (5)	C4—C5—C8—C9	−111.3 (4)
F2—C9—C8—C10	178.9 (4)	C4—C5—C8—C10	124.7 (4)
F3—C9—C8—C5	171.0 (4)	C5—C8—C10—C11	−76.9 (4)
F3—C9—C8—C10	−63.0 (5)	C6—C5—C8—C9	67.2 (4)
O1—C2—C3—C4	179.6 (3)	C6—C5—C8—C10	−56.8 (5)
O1—C2—C7—C6	179.8 (4)	C7—C6—C5—C8	−179.4 (4)
O2—C11—N1—C12	−176.4 (3)	C9—C8—C10—C11	158.3 (3)
O2—C11—N1—C14	−1.9 (4)	C10—C11—N1—C12	2.0 (5)
O2—C11—C10—C8	−9.7 (5)	C10—C11—N1—C14	176.5 (3)
O3—C12—O4—C13	178.0 (4)	C11—N1—C14—C13	−167.5 (3)
O3—C12—N1—C11	−9.6 (6)	C11—N1—C14—C15	71.7 (4)
O3—C12—N1—C14	175.5 (4)	C12—O4—C13—C14	7.6 (4)
O4—C12—N1—C11	171.2 (3)	C12—N1—C14—C13	7.8 (4)
O4—C12—N1—C14	−3.6 (4)	C12—N1—C14—C15	−113.1 (4)
O4—C13—C14—N1	−8.8 (4)	C13—C14—C15—C16	−56.8 (5)
O4—C13—C14—C15	112.6 (3)	C14—C15—C16—C17	−79.1 (5)
N1—C11—C10—C8	172.0 (3)	C14—C15—C16—C21	99.8 (4)
N1—C12—O4—C13	−2.8 (4)	C15—C16—C17—C18	178.7 (3)
N1—C14—C15—C16	57.0 (5)	C15—C16—C21—C20	−177.6 (4)
C1—O1—C2—C3	179.5 (4)	C16—C17—C18—C19	0.0 (6)
C1—O1—C2—C7	−0.9 (5)	C16—C21—C20—C19	−2.1 (8)
C2—C3—C4—C5	0.1 (6)	C17—C16—C21—C20	1.3 (6)
C2—C7—C6—C5	1.0 (6)	C17—C18—C19—C20	−0.8 (8)
C3—C2—C7—C6	−0.5 (5)	C18—C17—C16—C21	−0.3 (5)
C3—C4—C5—C6	0.3 (5)	C18—C19—C20—C21	1.9 (9)
C3—C4—C5—C8	178.9 (3)

Symmetry codes: (i) x, y, z−1; (ii) x+1/2, −y+1/2, −z; (iii) −x+1/2, −y+1, z+1/2; (iv) −x+1, y+1/2, −z+1/2; (v) x−1/2, −y+1/2, −z+1; (vi) −x+1/2, −y+1, z−1/2; (vii) x, y, z+1; (viii) x+1/2, −y+1/2, −z+1.