(2R,4S,7R,9S)-5,6-Diisopropyl-1,10-dimeth­oxy-3,8-dimethyl­deca-3,4,6,7-tetra­ene-2,9-diol

The molecule of the title compound, C₂₀H₃₄O₄, is centrosymmetric. In the crystal structure, a network of O—H...O hydrogen bonds result in each mol­ecule being linked to four neighbouring mol­ecules and a two-dimensional net is formed.

Key indicators

• Single-crystal X-ray study
• T = 173 K
• Mean [sigma](C-C) = 0.003 Å
• R factor = 0.037
• wR factor = 0.064
• Data-to-parameter ratio = 15.6

checkCIF/PLATON results

No syntax errors found



Alert level C
PLAT026_ALERT_3_C Ratio Observed / Unique Reflections too Low ....         45 Perc.
PLAT230_ALERT_2_C Hirshfeld Test Diff for    C1     -   C2      ..       5.76 su
PLAT230_ALERT_2_C Hirshfeld Test Diff for    C2     -   C3      ..       5.06 su
PLAT380_ALERT_4_C Check Incorrectly? Oriented X(sp2)-Methyl Moiety        C10
PLAT790_ALERT_4_C Centre of Gravity not Within Unit Cell: Resd.  #          1
              C20 H34 O4

Alert level G
PLAT793_ALERT_1_G Check the Absolute Configuration of C4     = ...          S

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

   1 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
   1 ALERT type 3 Indicator that the structure quality may be low
   2 ALERT type 4 Improvement, methodology, query or suggestion
   0 ALERT type 5 Informative message, check

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S1. Comment

The title compound, (I), is one of two diastereomeric bisallenes produced from the S_N2'-substitution of a bis-propargyl oxirane with a diisopropyl magnesiumcuprate. The crystal structure determination of (I) has been carried out to establish the relative configuration of the stereogenic elements.

The complete molecule (Fig. 1) is generated by inversion symmetry. In the crystal, a network of O—H···O hydrogen bonds (Table 1) leads to a two-dimensional network.

Related literature

For details of the synthesis, see: Krause & Hoffmann-Röder (2004).

S2. Experimental

In a dry flask (Krause & Hoffmann-Röder, 2004) equipped with a magnetic stirring bar, a suspension of CuCN (386 mg, 4.3 mmol) in dry THF (20 ml) was cooled to 223 K under argon. At this temperature, isopropylmagnesium chloride (4.3 ml, 8.6 mmol, 2.0 M solution in THF) was added dropwise, and the mixture was stirred at 223 K for 30 minutes. Then a solution of 3-(methoxymethyl)-2-[4-(3-methoxymethyl-2-methyloxiran-2-yl] buta-1,3-diynyl)-2-methyloxirane in THF (4 ml) was added dropwise over 15 min at 223 K, and stirring was continued for 2 h at this temperature. The reaction mixture was then hydrolyzed with aq. satd. NH₄Cl (4 ml) and filtered through a short pad of Celite; the filtrate was dried with Na₂SO₄ and the solvent was removed in vacuo. The residue was purified by column chromatography on silica gel (cyclohexane/ethyl acetate, 2:1) to give the title bisallene as a colourless solid (258 mg, 42.3%) along with the second diastereomer (257 mg, 42.2%) which was a colourless oil. The title compound was taken up in ethyl acetate, and dichloromethane was added dropwise until it was completely dissolved. Colourless blocks of (I) were obtained by slow evaporation at ambient temperature; m.p. 389 K.

¹H NMR (400 MHz, CDCl₃): δ 4.26–4.2.4 (m, 2 H), 3.50 (dd, J = 3.2/9.6 Hz 2 H), 3.40 (s, 6 H), 3.40 (t, J = 8.4 Hz, 2 H), 2.34–2.27 (m, 2 H), 2.21 (d, J = 3.2 Hz, 2H), 1.78 (s, 6 H), 1.00 (t, J = 6.4 Hz, 12 H). ¹³C NMR (100 MHz, CDCl₃): d 198.3, 113.2, 104.8, 75.7, 71.3, 58.9, 29.6, 22.9, 22.3, 15.3. HRMS (ESI): calcd for C₂₀H₃₅O₄ (M+H): 339.2457, found 339.2531.

S3. Refinement

H atoms at C atoms were placed in calculated positions, with C—H = 0.98–1.00 Å and were refined as riding, with U_iso(H)= 1.5U_eq(C) for methyl and 1.2U_eq(C) for all other H atoms; the methyl groups were allowed to rotate but not to tip. The position of H2A was taken from a difference map and the coordinates were refined with U_iso(H)= 1.5U_eq(O).

Computing details

Data collection: COLLECT (Nonius, 1998); cell refinement: DENZO and SCALEPACK (Otwinowski & Minor, 1997); data reduction: DENZO and SCALEPACK (Otwinowski & Minor, 1997); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: SHELXTL-Plus (Sheldrick, 1991); software used to prepare material for publication: SHELXL97 (Sheldrick, 1997) and PLATON (Spek, 2003).

Figures

Fig. 1. : The molecular structure of (I) showing displacement ellipsoids for the non-hydrogen atoms at the 50% probability level. The atoms with suffix A are generated by the symmetry operation (-1 - x, 1 - y, -1 - z).

(2R,4S,7R,9S)-5,6-Diisopropyl-1,10-dimethoxy-3,8-dimethyldeca- 3,4,6,7-tetraene-2,9-diol

Crystal data

C20H34O4	F(000) = 372
Mr = 338.47	Dx = 1.136 Mg m^−3
Monoclinic, P21/n	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2yn	Cell parameters from 12747 reflections
a = 7.1583 (11) Å	θ = 2.9–25.4°
b = 7.1326 (8) Å	µ = 0.08 mm^−1
c = 19.575 (2) Å	T = 173 K
β = 97.956 (7)°	Block, colourless
V = 989.8 (2) Å^3	0.15 × 0.15 × 0.13 mm
Z = 2

Data collection

Nonius KappaCCD diffractometer	815 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.036
Graphite monochromator	θmax = 25.4°, θmin = 2.9°
Detector resolution: 19 vertical, 18 horizontal pixels mm^-1	h = −8→8
464 frames via ω–rotation (Δω=1°) and two times 50 s per frame (five sets at different κ–angles) scans	k = −8→8
12747 measured reflections	l = −23→23
1814 independent reflections

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)] = 0.037	Hydrogen site location: difmap and geom
wR(F^2) = 0.064	H atoms treated by a mixture of independent and constrained refinement
S = 0.93	w = 1/[σ^2(Fo^2) + (0.0075P)^2] where P = (Fo^2 + 2Fc^2)/3
1814 reflections	(Δ/σ)max < 0.001
116 parameters	Δρmax = 0.15 e Å^−3
0 restraints	Δρmin = −0.14 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
O1	−0.44166 (17)	0.76006 (17)	0.25645 (6)	0.0387 (4)
O2	−0.07509 (18)	0.65573 (18)	0.23350 (6)	0.0380 (4)
H2A	−0.077 (3)	0.533 (2)	0.2385 (9)	0.046*
C1	−0.4326 (3)	0.4524 (3)	0.02719 (9)	0.0273 (5)
C2	−0.3061 (3)	0.5491 (3)	0.06830 (10)	0.0281 (5)
C3	−0.1788 (3)	0.6388 (3)	0.11019 (9)	0.0283 (5)
C4	−0.2167 (3)	0.7141 (3)	0.17929 (9)	0.0303 (5)
H4A	−0.2100	0.8539	0.1768	0.036*
C5	−0.4122 (2)	0.6645 (3)	0.19503 (9)	0.0333 (5)
H5A	−0.5085	0.7032	0.1563	0.040*
H5B	−0.4226	0.5274	0.2014	0.040*
C6	−0.4500 (2)	0.2422 (2)	0.03559 (9)	0.0286 (5)
H6A	−0.4812	0.1862	−0.0114	0.034*
C7	−0.6130 (2)	0.1963 (2)	0.07667 (9)	0.0403 (6)
H7A	−0.7289	0.2568	0.0547	0.060*
H7B	−0.5821	0.2427	0.1240	0.060*
H7C	−0.6318	0.0602	0.0774	0.060*
C8	−0.2682 (3)	0.1514 (2)	0.07011 (9)	0.0385 (6)
H8A	−0.1640	0.1858	0.0450	0.058*
H8B	−0.2830	0.0148	0.0697	0.058*
H8C	−0.2407	0.1953	0.1179	0.058*
C9	−0.6108 (3)	0.7024 (3)	0.28127 (9)	0.0484 (6)
H9A	−0.6250	0.7717	0.3235	0.073*
H9B	−0.6046	0.5677	0.2913	0.073*
H9C	−0.7192	0.7280	0.2461	0.073*
C10	0.0172 (2)	0.6760 (3)	0.09233 (9)	0.0394 (6)
H10A	0.0279	0.6231	0.0468	0.059*
H10B	0.1110	0.6173	0.1270	0.059*
H10C	0.0395	0.8115	0.0916	0.059*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
O1	0.0282 (9)	0.0535 (10)	0.0352 (9)	−0.0076 (7)	0.0077 (7)	−0.0123 (7)
O2	0.0298 (9)	0.0478 (9)	0.0341 (8)	0.0007 (9)	−0.0040 (7)	0.0025 (9)
C1	0.0288 (14)	0.0291 (13)	0.0249 (13)	−0.0010 (11)	0.0067 (10)	−0.0027 (11)
C2	0.0313 (14)	0.0288 (12)	0.0251 (12)	0.0072 (11)	0.0069 (11)	0.0049 (11)
C3	0.0282 (13)	0.0316 (13)	0.0249 (12)	0.0012 (11)	0.0025 (11)	0.0011 (10)
C4	0.0267 (13)	0.0357 (14)	0.0268 (12)	−0.0006 (10)	−0.0024 (10)	0.0031 (10)
C5	0.0291 (13)	0.0407 (14)	0.0284 (12)	−0.0029 (11)	−0.0014 (10)	−0.0043 (11)
C6	0.0291 (13)	0.0286 (13)	0.0269 (12)	−0.0024 (11)	−0.0009 (10)	−0.0018 (10)
C7	0.0402 (15)	0.0389 (15)	0.0418 (13)	−0.0062 (11)	0.0059 (11)	0.0029 (11)
C8	0.0374 (14)	0.0329 (13)	0.0435 (13)	−0.0005 (11)	−0.0009 (11)	0.0033 (11)
C9	0.0293 (14)	0.0703 (18)	0.0467 (14)	−0.0060 (12)	0.0092 (11)	−0.0071 (12)
C10	0.0300 (15)	0.0500 (15)	0.0385 (14)	−0.0041 (11)	0.0054 (11)	−0.0048 (11)

Geometric parameters (Å, º)

O1—C5	1.4230 (17)	C6—C7	1.541 (2)
O1—C9	1.4266 (18)	C6—H6A	1.0000
O2—C4	1.424 (2)	C7—H7A	0.9800
O2—H2A	0.881 (16)	C7—H7B	0.9800
C1—C2	1.319 (2)	C7—H7C	0.9800
C1—C1^i	1.498 (3)	C8—H8A	0.9800
C1—C6	1.515 (2)	C8—H8B	0.9800
C2—C3	1.306 (2)	C8—H8C	0.9800
C3—C4	1.514 (2)	C9—H9A	0.9800
C3—C10	1.516 (2)	C9—H9B	0.9800
C4—C5	1.516 (2)	C9—H9C	0.9800
C4—H4A	1.0000	C10—H10A	0.9800
C5—H5A	0.9900	C10—H10B	0.9800
C5—H5B	0.9900	C10—H10C	0.9800
C6—C8	1.525 (2)
C5—O1—C9	112.43 (14)	C7—C6—H6A	107.9
C4—O2—H2A	110.6 (12)	C6—C7—H7A	109.5
C2—C1—C1^i	121.1 (2)	C6—C7—H7B	109.5
C2—C1—C6	120.72 (17)	H7A—C7—H7B	109.5
C1^i—C1—C6	118.1 (2)	C6—C7—H7C	109.5
C3—C2—C1	177.8 (2)	H7A—C7—H7C	109.5
C2—C3—C4	122.63 (18)	H7B—C7—H7C	109.5
C2—C3—C10	121.93 (18)	C6—C8—H8A	109.5
C4—C3—C10	115.45 (16)	C6—C8—H8B	109.5
O2—C4—C3	111.40 (15)	H8A—C8—H8B	109.5
O2—C4—C5	111.23 (14)	C6—C8—H8C	109.5
C3—C4—C5	112.53 (15)	H8A—C8—H8C	109.5
O2—C4—H4A	107.1	H8B—C8—H8C	109.5
C3—C4—H4A	107.1	O1—C9—H9A	109.5
C5—C4—H4A	107.1	O1—C9—H9B	109.5
O1—C5—C4	107.99 (14)	H9A—C9—H9B	109.5
O1—C5—H5A	110.1	O1—C9—H9C	109.5
C4—C5—H5A	110.1	H9A—C9—H9C	109.5
O1—C5—H5B	110.1	H9B—C9—H9C	109.5
C4—C5—H5B	110.1	C3—C10—H10A	109.5
H5A—C5—H5B	108.4	C3—C10—H10B	109.5
C1—C6—C8	112.96 (16)	H10A—C10—H10B	109.5
C1—C6—C7	110.27 (15)	C3—C10—H10C	109.5
C8—C6—C7	109.88 (14)	H10A—C10—H10C	109.5
C1—C6—H6A	107.9	H10B—C10—H10C	109.5
C8—C6—H6A	107.9
C2—C3—C4—O2	128.7 (2)	C3—C4—C5—O1	−173.06 (14)
C10—C3—C4—O2	−51.8 (2)	C2—C1—C6—C8	−24.8 (3)
C2—C3—C4—C5	3.0 (3)	C1^i—C1—C6—C8	157.52 (19)
C10—C3—C4—C5	−177.50 (17)	C2—C1—C6—C7	98.6 (2)
C9—O1—C5—C4	−171.66 (15)	C1^i—C1—C6—C7	−79.1 (2)
O2—C4—C5—O1	61.14 (19)

Symmetry code: (i) −x−1, −y+1, −z.

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O2—H2A···O1^ii	0.881 (16)	1.953 (16)	2.8304 (18)	173.8 (17)

Symmetry code: (ii) −x−1/2, y−1/2, −z+1/2.