(2aR*,5S*,6aS*,8aS*,E)-Ethyl 5-hy­droxy-7,7,8a-trimethyl-8-oxo-2,2a,6,6a,7,8,8a,8b-octa­hydro-1H-penta­leno[1,6-bc]oxepine-4-carboxyl­ate

Mehta, G.; Kumar, C.S.A.; Sen, S.

doi:10.1107/S1600536812046776

organic compounds

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ISSN: 2056-9890

Volume 68| Part 12| December 2012| Pages o3392-o3393

doi:10.1107/S1600536812046776

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(2aR,5S,6aS,8aS,E)-Ethyl 5-hydroxy-7,7,8a-trimethyl-8-oxo-2,2a,6,6a,7,8,8a,8b-octahydro-1H-pentaleno[1,6-bc]oxepine-4-carboxylate

Goverdhan Mehta,^a ^*‡ C. S. Ananda Kumar ^a and Saikat Sen ^a

^aDepartment of Organic Chemistry, Indian Institute of Science, Bangalore 560 012, India
^*Correspondence e-mail: gmsc@uohyd.ernet.in, gm@orgchem.iisc.ernet.in

(Received 2 October 2012; accepted 13 November 2012; online 24 November 2012)

The title compound, C₁₇H₂₄O₅, featuring a 2-carbethoxy-3-oxepanone unit in its intramolecularly O—H⋯O hydrogen-bonded enol form, was obtained via [(CF₃CO₂)₂Rh]₂-catalysed intramolecular O—H bond insertion in the α-diazo-ω-hydroxy-β-ketoester, ethyl 4-[(1S,3aS,6R,6aS)-6-hydroxy-2,2,3a-trimethyl-3-oxo-octahydropentalen-1-yl]-2-diazo-3-oxobutanoate. The seven-membered oxacyclic ring, thus constructed on a cis-fused diquinane platform, was found to adopt a distorted boat–sofa conformation.

Related literature

For rhodium carbenoid-mediated intermolecular O—H insertion reactions and their application to natural product synthesis, see: Paulissen et al. (1973 ); Cox et al. (1994 ); Haigh (1994 ); Aller et al. (1995 ); Shi et al. (1995 ); Bulugahapitiya et al. (1997 ); Moody & Miller (1998 ); Nelson et al. (2000 ); Medeiros & Wood (2010 ); Freeman et al. (2010 ); Morton et al. (2012 ). For rhodium-catalysed intramolecular O—H insertion reactions, see: Paulissen et al. (1974 ); Moyer et al. (1985 ); Moody & Taylor (1987 ); Heslin & Moody (1988 ); Davies et al. (1990 ); Moody et al. (1992 ); Sarabia-Garciá et al. (1994); Padwa & Sá (1999 ); Im et al. (2005 ). For reviews on rhodium-mediated C—H insertion reactions, see: Doyle et al. (2010 ); Davies & Morton (2011 ). For the construction of an angularly fused triquinane skeleton via Rh^II-catalysed intramolecular C—H insertion, see: Srikrishna et al. (2012 ). For the isolation and synthesis of penifulvin A, see: Shim et al. (2006 ); Gaich & Mulzer (2009 ); Mehta & Khan (2012 ). For the application of p-acetamidobenzenesulfonyl azide as a diazo transfer reagent, see: Baum et al. (1987 ). For ring conformations, see: Cremer & Pople (1975 ); Boessenkool & Boeyens (1980 ).

Experimental

Crystal data

C₁₇H₂₄O₅
M_r = 308.36
Orthorhombic, P b c a
a = 8.447 (5) Å
b = 18.454 (14) Å
c = 21.735 (15) Å
V = 3388 (4) Å³
Z = 8
Mo Kα radiation
μ = 0.09 mm⁻¹
T = 291 K
0.20 × 0.18 × 0.08 mm

Data collection

Bruker APEXII CCD diffractometer
Absorption correction: multi-scan (SADABS; Sheldrick, 2003 ) T_min = 0.983, T_max = 0.993
14606 measured reflections
3153 independent reflections
1408 reflections with I > 2σ(I)
R_int = 0.087

Refinement

R[F² > 2σ(F²)] = 0.053
wR(F²) = 0.149
S = 0.89
3153 reflections
207 parameters
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.17 e Å⁻³
Δρ_min = −0.17 e Å⁻³

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O2—H2O⋯O4	0.93 (3)	1.69 (3)	2.565 (4)	155 (3)

Data collection: APEX2 (Bruker, 2007 ); cell refinement: SAINT (Bruker, 2007); data reduction: SAINT; program(s) used to solve structure: SIR92 (Altomare et al., 1994 ); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ); molecular graphics: ORTEP-3 for Windows (Farrugia, 2012 ); software used to prepare material for publication: PLATON (Spek, 2009 ).

Supporting information

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536812046776/ds2220sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536812046776/ds2220Isup2.hkl

checkCIF report

Comment top

Rhodium carbenoid mediated O—H insertion provides a facile means of transforming diazo-compounds into diverse range of functionalized ethers (Paulissen, et al., 1973; Cox, et al. 1994; Haigh, 1994; Aller et al., 1995; Shi et al., 1995; Bulugahapitiya et al., 1997; Moody & Miller, 1998; Morton et al., 2012). Hence the methodology has proven to be a useful stratagem in the synthetic acquisition of several natural products (Nelson et al., 2000; Medeiros & Wood, 2010; Freeman, et al. 2010). While not as extensively utilized or studied as the intermolecular variants, intramolecular interception of rhodium carbenoids by hydroxy nucleophiles can, nevertheless, afford an effective route to cyclic ethers and lactones (Paulissen et al., 1974; Moyer et al., 1985; Moody & Taylor, 1987; Heslin & Moody, 1988; Moody et al. 1992; Sarabia-García et al., 1994; Padwa & Sá, 1999; Im et al., 2005). Indeed, studies by Moody and co-workers have shown that rhodium(II) acetate catalysed cyclization in diazoalcohols may even be employed as a practical method for accessing medium-ring oxacycles - oxepanes, in particular, wherein interference from competing C—H insertion reactions do not appear to be significant (Heslin & Moody, 1988; Davies et al., 1990).

Against this background, we report herein the crystal structure of the title compound 1, a 2-carbethoxy-3-oxepanone embedded in a tricyclic framework, that was obtained as the sole isolable product in the rhodium(II) trifluroacetate mediated decomposition of the α-diazo-ω-hydroxy-β-ketoester 2 (Figure 1). Originally envisaged as an entry point to an angularly fused triquinane skeleton via Rh(II) catalyzed intramolecular C—H insertion (Doyle et al., 2010; Davies & Morton, 2011; Srikrishna et al., 2012) en route to the natural product penifulvin A (Shim et al., 2006; Gaich & Mulzer, 2009; Mehta & Khan, 2012), the diazoester 2 was prepared from the β-ketoester 3 via a diazo transfer reaction to the activated methylene group in 3 (Baum et al., 1987).

The crystal structure of 1 was solved and refined in the centrosymmetric orthorhombic space group Pbcn (Z = 8). The 2-carbethoxy-3-oxepanone moiety in 1 was found to exist in the intramolecularly O—H···O hydrogen bonded enol form (Figure 2). As indicated by its puckering parameters (q₂ = 0.915 (3) Å, q₃ = 0.310 (3) Å, ϕ₂ = 193.59 (17)°, ϕ₃ = 118.9 (5)°, Q_T = 0.967 (2) Å), the seven-membered oxacyclic ring adopted a distorted boat-sofa conformation (Cremer & Pople, 1975; Boessenkool & Boeyens, 1980). Crystal packing in 1 was effected primarily via the agency of weak van der Waals interactions, though short C—H···O contacts (C8—H8···O2) could be discerned among the molecules.

Related literature top

For rhodium carbenoid-mediated intermolecular O—H insertion reactions and their application to natural product synthesis, see: Paulissen et al. (1973); Cox et al. (1994); Haigh (1994); Aller et al. (1995); Shi et al. (1995); Bulugahapitiya et al. (1997); Moody & Miller (1998); Nelson et al. (2000); Medeiros & Wood (2010); Freeman et al. (2010); Morton et al. (2012). For rhodium-catalysed intramolecular O—H insertion reactions, see: Paulissen et al. (1974); Moyer et al. (1985); Moody & Taylor (1987); Heslin & Moody (1988); Davies et al. (1990); Moody et al. (1992); Sarabia-Garcá et al. (1994)9 Padwa & Sá (1999); Im et al. (2005). For recent reviews on rhodium-mediated C—H insertion reactions, see: Doyle et al. (2010); Davies & Morton (2011). For a recent report on the construction of an angularly fused triquinane skeleton via Rh^II-catalysed intramolecular C—H insertion, see: Srikrishna et al. (2012). For the isolation and synthesis of penifulvin A, see: Shim et al. (2006); Gaich & Mulzer (2009); Mehta & Khan (2012). For the application of p-acetamidobenzenesulfonyl azide as a diazo transfer reagent, see: Baum et al. (1987). For ring conformations, see: Cremer & Pople (1975); Boessenkool & Boeyens (1980).

Experimental top

As shown in Figure 1, the title compound 1 was prepared from the the β-ketoester 3 via the intermediate diazoester 2. Thus, 3, upon treatment with p-acetamidobenzenesulfonyl azide and triethylamine, afforded 2. The α-diazo-ω-hydroxy-β-ketoester 2 underwent smooth cyclization in presence of catalytic rhodium(II) trifluoroacetate dimer to deliver the oxepanone 1, which crystallized as thin colorless plates from 1:1 dichloromethane-hexanes.

Computing details top

Data collection: APEX2 (Bruker, 2007); cell refinement: SAINT (Bruker, 2007); data reduction: SAINT (Bruker, 2007); program(s) used to solve structure: SIR92 (Altomare et al., 1994); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 for Windows (Farrugia, 2012); software used to prepare material for publication: PLATON (Spek, 2009).

Figures top

	Fig. 1. Preparation of the title compound 1 from the β-ketoester 3.
	Fig. 2. View of the title compound 1, with the atom numbering scheme of the asymmetric unit. Displacement ellipsoids for non-H atoms are drawn at the 30% probability level.

(2aR*,5S*,6aS*,8aS*,E)-Ethyl 5-hydroxy-7,7,8a-trimethyl-8-oxo-2,2a,6,6a,7,8,8a,8b-octahydro-1H- pentaleno[1,6-bc]oxepine-4-carboxylate top

Crystal data top

C₁₇H₂₄O₅	F(000) = 1328
M_r = 308.36	D_x = 1.209 Mg m⁻³
Orthorhombic, Pbca	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ac 2ab	Cell parameters from 939 reflections
a = 8.447 (5) Å	θ = 2.8–19.5°
b = 18.454 (14) Å	µ = 0.09 mm⁻¹
c = 21.735 (15) Å	T = 291 K
V = 3388 (4) Å³	Plate, colorless
Z = 8	0.20 × 0.18 × 0.08 mm

Data collection top

Bruker APEXII CCD diffractometer	3153 independent reflections
Radiation source: fine-focus sealed tube	1408 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.087
ϕ and ω scans	θ_max = 25.5°, θ_min = 1.9°
Absorption correction: multi-scan (SADABS; Sheldrick, 2003)	h = −10→7
T_min = 0.983, T_max = 0.993	k = −22→18
14606 measured reflections	l = −26→26

Refinement top

Refinement on F²	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F² > 2σ(F²)] = 0.053	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.149	H atoms treated by a mixture of independent and constrained refinement
S = 0.89	w = 1/[σ²(F_o²) + (0.0717P)²] where P = (F_o² + 2F_c²)/3
3153 reflections	(Δ/σ)_max < 0.001
207 parameters	Δρ_max = 0.17 e Å⁻³
0 restraints	Δρ_min = −0.17 e Å⁻³

Crystal data top

C₁₇H₂₄O₅	V = 3388 (4) Å³
M_r = 308.36	Z = 8
Orthorhombic, Pbca	Mo Kα radiation
a = 8.447 (5) Å	µ = 0.09 mm⁻¹
b = 18.454 (14) Å	T = 291 K
c = 21.735 (15) Å	0.20 × 0.18 × 0.08 mm

Data collection top

Bruker APEXII CCD diffractometer	3153 independent reflections
Absorption correction: multi-scan (SADABS; Sheldrick, 2003)	1408 reflections with I > 2σ(I)
T_min = 0.983, T_max = 0.993	R_int = 0.087
14606 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.053	0 restraints
wR(F²) = 0.149	H atoms treated by a mixture of independent and constrained refinement
S = 0.89	Δρ_max = 0.17 e Å⁻³
3153 reflections	Δρ_min = −0.17 e Å⁻³
207 parameters

Special details top

Geometry. All s.u.'s (except the s.u. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell s.u.'s are taken into account individually in the estimation of s.u.'s in distances, angles and torsion angles; correlations between s.u.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell s.u.'s is used for estimating s.u.'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 > 2σ(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 (Å²) top

	x	y	z	U_iso*/U_eq
O1	0.1027 (3)	0.15812 (15)	1.02261 (10)	0.0990 (9)
O2	0.0947 (2)	0.13477 (12)	0.69261 (9)	0.0655 (6)
H2O	0.125 (4)	0.0976 (18)	0.6660 (15)	0.090 (12)*
O3	0.1391 (2)	−0.00529 (10)	0.80956 (7)	0.0545 (5)
O4	0.1993 (2)	0.01550 (12)	0.64764 (8)	0.0717 (6)
O5	0.2612 (2)	−0.07327 (12)	0.71407 (8)	0.0678 (6)
C1	0.0661 (3)	0.12205 (14)	0.86389 (11)	0.0471 (7)
H1	−0.0058	0.0810	0.8699	0.057*
C2	0.0332 (3)	0.17697 (15)	0.91600 (12)	0.0544 (8)
C3	0.1256 (3)	0.14428 (17)	0.96932 (13)	0.0623 (8)
C4	0.2513 (3)	0.09177 (16)	0.94596 (12)	0.0568 (8)
C5	0.2035 (5)	0.01234 (18)	0.95976 (14)	0.0888 (11)
H5A	0.2518	−0.0039	0.9978	0.107*
H5B	0.0895	0.0083	0.9637	0.107*
C6	0.2602 (5)	−0.03189 (19)	0.90749 (14)	0.0906 (12)
H6A	0.1898	−0.0726	0.9006	0.109*
H6B	0.3655	−0.0504	0.9158	0.109*
C7	0.2627 (3)	0.01697 (15)	0.85202 (12)	0.0575 (8)
H7	0.3661	0.0139	0.8317	0.069*
C8	0.2347 (3)	0.09461 (14)	0.87520 (11)	0.0474 (7)
H8	0.3125	0.1280	0.8574	0.057*
C9	0.4153 (4)	0.1103 (2)	0.97087 (15)	0.0970 (12)
H9A	0.4449	0.1580	0.9573	0.145*
H9B	0.4908	0.0757	0.9559	0.145*
H9C	0.4133	0.1090	1.0150	0.145*
C10	−0.1415 (4)	0.1859 (2)	0.93120 (14)	0.0795 (11)
H10A	−0.1868	0.1394	0.9400	0.119*
H10B	−0.1952	0.2072	0.8967	0.119*
H10C	−0.1527	0.2168	0.9664	0.119*
C11	0.1093 (4)	0.25222 (16)	0.90386 (15)	0.0781 (10)
H11A	0.1031	0.2811	0.9405	0.117*
H11B	0.0537	0.2761	0.8711	0.117*
H11C	0.2183	0.2460	0.8925	0.117*
C12	0.0415 (3)	0.14979 (16)	0.79823 (11)	0.0569 (8)
H12A	−0.0704	0.1595	0.7925	0.068*
H12B	0.0971	0.1955	0.7940	0.068*
C13	0.0951 (3)	0.10042 (16)	0.74780 (12)	0.0510 (7)
C14	0.1445 (3)	0.03157 (16)	0.75362 (11)	0.0512 (7)
C15	0.2038 (3)	−0.00865 (17)	0.70042 (13)	0.0572 (8)
C16	0.3258 (4)	−0.11534 (19)	0.66252 (15)	0.0833 (11)
H16A	0.2406	−0.1329	0.6366	0.100*
H16B	0.3950	−0.0852	0.6378	0.100*
C17	0.4146 (6)	−0.1765 (2)	0.68814 (18)	0.1264 (17)
H17A	0.4935	−0.1587	0.7161	0.190*
H17B	0.4650	−0.2027	0.6554	0.190*
H17C	0.3435	−0.2081	0.7097	0.190*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
O1	0.113 (2)	0.137 (2)	0.0465 (13)	0.0369 (16)	−0.0008 (12)	−0.0152 (14)
O2	0.0791 (15)	0.0722 (16)	0.0452 (12)	0.0013 (12)	−0.0053 (10)	0.0083 (12)
O3	0.0605 (13)	0.0555 (13)	0.0474 (11)	−0.0043 (9)	0.0016 (9)	−0.0012 (9)
O4	0.0820 (16)	0.0883 (16)	0.0448 (12)	0.0032 (12)	0.0027 (10)	−0.0031 (11)
O5	0.0850 (16)	0.0645 (14)	0.0540 (12)	0.0051 (12)	0.0061 (10)	−0.0092 (11)
C1	0.0407 (18)	0.0550 (17)	0.0456 (16)	−0.0004 (13)	−0.0013 (12)	−0.0012 (13)
C2	0.0495 (19)	0.060 (2)	0.0541 (17)	0.0038 (15)	−0.0001 (13)	−0.0068 (15)
C3	0.063 (2)	0.078 (2)	0.0463 (18)	−0.0012 (17)	−0.0008 (15)	−0.0052 (16)
C4	0.054 (2)	0.073 (2)	0.0438 (15)	0.0052 (16)	−0.0048 (13)	−0.0029 (15)
C5	0.117 (3)	0.085 (3)	0.064 (2)	0.019 (2)	0.0199 (19)	0.023 (2)
C6	0.128 (3)	0.076 (2)	0.067 (2)	0.010 (2)	−0.022 (2)	0.013 (2)
C7	0.058 (2)	0.0618 (19)	0.0524 (16)	0.0087 (15)	−0.0061 (14)	−0.0047 (15)
C8	0.0385 (17)	0.0557 (18)	0.0481 (15)	0.0009 (14)	−0.0004 (12)	−0.0002 (13)
C9	0.060 (2)	0.151 (4)	0.080 (2)	0.010 (2)	−0.0213 (18)	−0.031 (2)
C10	0.059 (2)	0.103 (3)	0.076 (2)	0.0165 (19)	0.0071 (17)	−0.0200 (19)
C11	0.091 (2)	0.063 (2)	0.081 (2)	−0.0007 (19)	−0.0015 (18)	−0.0131 (18)
C12	0.059 (2)	0.0625 (19)	0.0496 (16)	0.0101 (15)	−0.0062 (13)	0.0010 (14)
C13	0.0500 (18)	0.063 (2)	0.0404 (15)	−0.0043 (15)	−0.0073 (12)	0.0002 (15)
C14	0.0520 (19)	0.063 (2)	0.0388 (15)	−0.0052 (15)	0.0005 (12)	−0.0016 (14)
C15	0.054 (2)	0.064 (2)	0.0535 (19)	−0.0055 (17)	0.0008 (14)	−0.0021 (16)
C16	0.100 (3)	0.077 (2)	0.073 (2)	0.005 (2)	0.0090 (19)	−0.026 (2)
C17	0.194 (5)	0.076 (3)	0.109 (3)	0.047 (3)	0.008 (3)	−0.010 (2)

Geometric parameters (Å, º) top

O1—C3	1.202 (3)	C6—H6B	0.9700
O2—C13	1.357 (3)	C7—C8	1.537 (4)
O2—H2O	0.93 (3)	C7—H7	0.9800
O3—C14	1.394 (3)	C8—H8	0.9800
O3—C7	1.452 (3)	C9—H9A	0.9600
O4—C15	1.231 (3)	C9—H9B	0.9600
O5—C15	1.321 (3)	C9—H9C	0.9600
O5—C16	1.468 (3)	C10—H10A	0.9600
C1—C12	1.530 (3)	C10—H10B	0.9600
C1—C8	1.531 (3)	C10—H10C	0.9600
C1—C2	1.545 (3)	C11—H11A	0.9600
C1—H1	0.9800	C11—H11B	0.9600
C2—C10	1.521 (4)	C11—H11C	0.9600
C2—C3	1.522 (4)	C12—C13	1.496 (4)
C2—C11	1.553 (4)	C12—H12A	0.9700
C3—C4	1.525 (4)	C12—H12B	0.9700
C4—C9	1.526 (4)	C13—C14	1.343 (4)
C4—C8	1.545 (4)	C14—C15	1.462 (4)
C4—C5	1.550 (4)	C16—C17	1.465 (5)
C5—C6	1.479 (4)	C16—H16A	0.9700
C5—H5A	0.9700	C16—H16B	0.9700
C5—H5B	0.9700	C17—H17A	0.9600
C6—C7	1.505 (4)	C17—H17B	0.9600
C6—H6A	0.9700	C17—H17C	0.9600

C13—O2—H2O	102 (2)	C4—C8—H8	110.7
C14—O3—C7	113.1 (2)	C4—C9—H9A	109.5
C15—O5—C16	116.3 (2)	C4—C9—H9B	109.5
C12—C1—C8	112.7 (2)	H9A—C9—H9B	109.5
C12—C1—C2	116.1 (2)	C4—C9—H9C	109.5
C8—C1—C2	105.5 (2)	H9A—C9—H9C	109.5
C12—C1—H1	107.4	H9B—C9—H9C	109.5
C8—C1—H1	107.4	C2—C10—H10A	109.5
C2—C1—H1	107.4	C2—C10—H10B	109.5
C10—C2—C3	112.0 (2)	H10A—C10—H10B	109.5
C10—C2—C1	113.9 (2)	C2—C10—H10C	109.5
C3—C2—C1	101.9 (2)	H10A—C10—H10C	109.5
C10—C2—C11	110.0 (3)	H10B—C10—H10C	109.5
C3—C2—C11	105.7 (2)	C2—C11—H11A	109.5
C1—C2—C11	112.8 (2)	C2—C11—H11B	109.5
O1—C3—C2	124.6 (3)	H11A—C11—H11B	109.5
O1—C3—C4	124.6 (3)	C2—C11—H11C	109.5
C2—C3—C4	110.8 (2)	H11A—C11—H11C	109.5
C3—C4—C9	111.8 (2)	H11B—C11—H11C	109.5
C3—C4—C8	104.3 (2)	C13—C12—C1	116.0 (2)
C9—C4—C8	115.3 (2)	C13—C12—H12A	108.3
C3—C4—C5	110.8 (2)	C1—C12—H12A	108.3
C9—C4—C5	112.3 (3)	C13—C12—H12B	108.3
C8—C4—C5	101.6 (2)	C1—C12—H12B	108.3
C6—C5—C4	106.8 (3)	H12A—C12—H12B	107.4
C6—C5—H5A	110.4	C14—C13—O2	121.7 (3)
C4—C5—H5A	110.4	C14—C13—C12	127.0 (3)
C6—C5—H5B	110.4	O2—C13—C12	111.3 (3)
C4—C5—H5B	110.4	C13—C14—O3	122.2 (2)
H5A—C5—H5B	108.6	C13—C14—C15	120.8 (3)
C5—C6—C7	106.8 (3)	O3—C14—C15	117.0 (3)
C5—C6—H6A	110.4	O4—C15—O5	123.2 (3)
C7—C6—H6A	110.4	O4—C15—C14	122.9 (3)
C5—C6—H6B	110.4	O5—C15—C14	114.0 (3)
C7—C6—H6B	110.4	C17—C16—O5	107.9 (3)
H6A—C6—H6B	108.6	C17—C16—H16A	110.1
O3—C7—C6	109.2 (3)	O5—C16—H16A	110.1
O3—C7—C8	111.2 (2)	C17—C16—H16B	110.1
C6—C7—C8	107.1 (2)	O5—C16—H16B	110.1
O3—C7—H7	109.8	H16A—C16—H16B	108.4
C6—C7—H7	109.8	C16—C17—H17A	109.5
C8—C7—H7	109.8	C16—C17—H17B	109.5
C1—C8—C7	113.5 (2)	H17A—C17—H17B	109.5
C1—C8—C4	104.8 (2)	C16—C17—H17C	109.5
C7—C8—C4	106.3 (2)	H17A—C17—H17C	109.5
C1—C8—H8	110.7	H17B—C17—H17C	109.5
C7—C8—H8	110.7

C12—C1—C2—C10	79.9 (3)	C2—C1—C8—C4	35.4 (3)
C8—C1—C2—C10	−154.5 (2)	O3—C7—C8—C1	16.3 (3)
C12—C1—C2—C3	−159.2 (2)	C6—C7—C8—C1	−103.0 (3)
C8—C1—C2—C3	−33.6 (3)	O3—C7—C8—C4	131.0 (2)
C12—C1—C2—C11	−46.3 (3)	C6—C7—C8—C4	11.7 (3)
C8—C1—C2—C11	79.3 (3)	C3—C4—C8—C1	−22.2 (3)
C10—C2—C3—O1	−38.1 (4)	C9—C4—C8—C1	−145.2 (3)
C1—C2—C3—O1	−160.2 (3)	C5—C4—C8—C1	93.0 (3)
C11—C2—C3—O1	81.8 (4)	C3—C4—C8—C7	−142.7 (2)
C10—C2—C3—C4	142.1 (3)	C9—C4—C8—C7	94.4 (3)
C1—C2—C3—C4	20.0 (3)	C5—C4—C8—C7	−27.4 (3)
C11—C2—C3—C4	−98.1 (3)	C8—C1—C12—C13	49.8 (3)
O1—C3—C4—C9	−53.5 (4)	C2—C1—C12—C13	171.6 (2)
C2—C3—C4—C9	126.4 (3)	C1—C12—C13—C14	8.5 (4)
O1—C3—C4—C8	−178.7 (3)	C1—C12—C13—O2	−169.0 (2)
C2—C3—C4—C8	1.1 (3)	O2—C13—C14—O3	−177.2 (2)
O1—C3—C4—C5	72.7 (4)	C12—C13—C14—O3	5.5 (4)
C2—C3—C4—C5	−107.5 (3)	O2—C13—C14—C15	1.5 (4)
C3—C4—C5—C6	144.6 (3)	C12—C13—C14—C15	−175.8 (3)
C9—C4—C5—C6	−89.5 (3)	C7—O3—C14—C13	−75.6 (3)
C8—C4—C5—C6	34.3 (3)	C7—O3—C14—C15	105.7 (3)
C4—C5—C6—C7	−28.1 (4)	C16—O5—C15—O4	1.9 (4)
C14—O3—C7—C6	−172.9 (2)	C16—O5—C15—C14	−178.6 (2)
C14—O3—C7—C8	69.1 (3)	C13—C14—C15—O4	−6.2 (4)
C5—C6—C7—O3	−110.5 (3)	O3—C14—C15—O4	172.5 (2)
C5—C6—C7—C8	10.0 (4)	C13—C14—C15—O5	174.3 (3)
C12—C1—C8—C7	−81.4 (3)	O3—C14—C15—O5	−7.0 (4)
C2—C1—C8—C7	151.0 (2)	C15—O5—C16—C17	167.3 (3)
C12—C1—C8—C4	163.1 (2)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
O2—H2O···O4	0.93 (3)	1.69 (3)	2.565 (4)	155 (3)

Experimental details

Crystal data
Chemical formula	C₁₇H₂₄O₅
M_r	308.36
Crystal system, space group	Orthorhombic, Pbca
Temperature (K)	291
a, b, c (Å)	8.447 (5), 18.454 (14), 21.735 (15)
V (Å³)	3388 (4)
Z	8
Radiation type	Mo Kα
µ (mm⁻¹)	0.09
Crystal size (mm)	0.20 × 0.18 × 0.08

Data collection
Diffractometer	Bruker APEXII CCD diffractometer
Absorption correction	Multi-scan (SADABS; Sheldrick, 2003)
T_min, T_max	0.983, 0.993
No. of measured, independent and observed [I > 2σ(I)] reflections	14606, 3153, 1408
R_int	0.087
(sin θ/λ)_max (Å⁻¹)	0.606

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.053, 0.149, 0.89
No. of reflections	3153
No. of parameters	207
H-atom treatment	H atoms treated by a mixture of independent and constrained refinement
Δρ_max, Δρ_min (e Å⁻³)	0.17, −0.17

Computer programs: APEX2 (Bruker, 2007), SAINT (Bruker, 2007), SIR92 (Altomare et al., 1994), SHELXL97 (Sheldrick, 2008), ORTEP-3 for Windows (Farrugia, 2012), PLATON (Spek, 2009).

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
O2—H2O···O4	0.93 (3)	1.69 (3)	2.565 (4)	155 (3)

Footnotes

‡Present address: School of Chemistry, University of Hyderabad, Hyderabad 500 046, India.

Acknowledgements

We thank the Department of Science and Technology (DST), India, for the CCD facility at the Indian Institute of Science (IISc), Bangalore. CSAK thanks the University Grants Commission for the award of a Dr D. S. Kothari post-doctoral fellowship. GM thanks the Government of India for the award of a National Research Professorship and acknowledges the current research support from the Eli Lilly and Jubilant–Bhartia Foundations.

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