Tris-β-diketones and related keto derivatives for use as building blocks in supramolecular chemistry

Article abstract of DOI:10.1016/j.tet.2006.12.071

The synthesis of three new tris-β-diketones and some derivatives is reported. In two cases facile alkaline hydrolysis of the diketone moieties yielded the corresponding keto compounds. These are readily functionalised to provide tripodal ligands.

Full text of DOI:10.1016/j.tet.2006.12.071

Tetrahedron 63 (2007) 1953–1958
Tris-b-diketones and related keto derivatives for use as building
blocks in supramolecular chemistry
a
a,y
David J. Bray,a Katrina A. Jolliffe,b, Leonard F. Lindoy and John C. McMurtrie
*
aCentre for Heavy Metals Research, School of Chemistry, The University of Sydney, NSW 2006, Australia
bSchool of Chemistry (F11), The University of Sydney, NSW 2006, Australia
Received 2 November 2006; revised 19 December 2006; accepted 21 December 2006
Available online 28 December 2006
Abstract—The synthesis of three new tris-b-diketones and some derivatives is reported. In two cases facile alkaline hydrolysis of the diketone
moieties yielded the corresponding keto compounds. These are readily functionalised to provide tripodal ligands.
Ó 2007 Elsevier Ltd. All rights reserved.
1. Introduction
cages and/or capsules.6–9 Use of the 1,3,5-trimethyl-2,4,6-
trisubstituted benzene derivative has in some instances
been proposed to favour the desirable preorganisation of
the three pendant ‘arms’ towards the same face of the
benzene core.10–13 Another benefit of use of the mesitylyl
moiety is that the required 1,3,5-trimethyl-2,4,6-tri(bromo-
methyl)benzene starting material is more readily prepared
than 1,3,5-tris(bromomethyl)benzene itself.14,15 We thus
chose to employ this mesitylene derivative as our starting
material for the synthesis of a number of tris-b-diketone
derivatives.
The b-diketone motif is a versatile metal coordinating ligand
that is readily derivatised and able to form complexes with
a wide range of metal ions. It has also been shown to be
an attractive ligand for incorporation into metallo-supra-
molecular structures.1,2 For example, many of the latter inves-
tigations have focused on systems in which two b-diketone
ligands are linked to a central spacer by their terminal carbon
atoms.1,3–5 Pairs of these ligands have been shown to coordi-
nate copper(II) ions in a square planar geometry resulting in
the formation of planar di- and trinuclear scaffolds, with the
uncoordinated axial sites on each metal centre available for
further coordination.
2. Results and discussion
The synthesis of scaffolds that bear more than two b-di-
ketone groups will provide building blocks for the self-as-
sembly of structures of higher dimensionality. In particular,
scaffolds bearing three b-diketone ligands have the potential
to form molecular cages and/or capsules upon the addition of
suitable metal ions. We now report the synthesis of some tris-
b-diketones based on a 1,3,5-trimethyl-2,4,6-trisubstituted
benzene (mesitylyl) core, together with attempts to form
molecular capsules from these ligands through metal coordi-
nation of the b-diketone groups.
Compounds 2–4 were readily prepared in high yield (>80%)
from tris(bromomethyl)mesitylene (1) and the correspond-
ing b-diketone by refluxing in tert-butanol in the presence
of t-BuOK (Scheme 1). The resulting b-diketones were all
1
readily purified and their H and 13C NMR spectra are in
accord with the presence of high levels of symmetry. In
all cases, only a single tautomer, the diketone form, was
observed by both 1H and 13C NMR spectroscopies in
deuterochloroform. This is in contrast to similar bis-b-
ketone derivatives in which a substantial percentage of the
enol tautomer is observed.16
The 1,3,5-trisubstituted benzyl moiety has been employed as
a convenient scaffold in the design and synthesis of many su-
pramolecular assemblies, including structures that resemble
The X-ray crystal structure analysis of 4 (Fig. 1) revealed
that this compound exists in the solid state as the keto tauto-
mer only, with the central carbon atoms of the b-diketone
groups all being sp3 hybridised. In addition, the oxygen-to-
oxygen distances for the three b-diketone groups are all
Keywords: b-Diketone; Tripodal scaffold; Alkaline hydrolysis; Tris-ketone.
* Corresponding author. Tel.: +61 2 9351 2297; fax: +61 2 9351 3329;
e-mail: jolliffe@chem.usyd.edu.au
˚
greater than 3.17 A, whereas oxygen-to-oxygen distances
in enolic b-diketone derivatives are typically less than
y
Present address: School of Physical and Chemical Sciences, Queensland
University of Technology, GPO Box 2434, Brisbane 4001, Australia.
17
˚
2.54 A.
0040–4020/$ - see front matter Ó 2007 Elsevier Ltd. All rights reserved.
doi:10.1016/j.tet.2006.12.071

1954
D. J. Bray et al. / Tetrahedron 63 (2007) 1953–1958
O
O
R
R
O
O
OH
R'
Br
R'
R
NaOH
R'
R
t-BuOK
t-BuOH
O
O
Br
R
R
O
Br
O
O
1
R'
R
O
2 R = R' = Me (97 %)
3 R = Me, R' = Ph (83 %)
4 R = R' = Ph (86 %)
5: R = Me (70 %)
6: R = Ph (92 %)
Scheme 1.
Attempts at forming transition-metal complexes of 2–4
using the normal procedure of heating with a metal salt in
the presence of base were unsuccessful. In each case, rather
than obtaining the desired metal complex upon cooling the
reaction mixture, we isolated white solids that contained
no metal ion. The difficulty in forming metal complexes is
in accordance with these compounds being unable to easily
tautomerise to the enolate derivative.16 We therefore attemp-
ted to pre-form the sodium enolate of 2 since it has been
shown previously that transmetallation of sodium acetyl-
acetonate with a variety of transition metals can be used to
form transition-metal complexes of acetylacetone without
the need to add further base.18,19 Attempts to form the
sodium salt of 2, by heating with NaOH in ethanol/water,20
resulted in the crystallisation of fine white needles that
exhibited a different habit to that of the starting compound.
However, spectroscopic analysis and an X-ray crystal struc-
ture determination (Fig. 2) confirmed that this product was
not the expected sodium salt, but was the tris-ketone deriva-
tive 5, resulting from alkaline hydrolysis of each of the
b-diketone groups (Scheme 1). The material isolated from
the attempts to directly form transition-metal complexes of
2 was also identified spectroscopically as 5.
Figure 2. ORTEP of 5 with ellipsoids shown at the 50% probability level.
least one proton on the central carbon position are somewhat
protected from hydrolysis due to the presence of keto–enol
tautomerism, which confers a partial double bond character
to the C–C bond, making cleavage more difficult. However,
for b-diketones with two non-hydrogen substituents on the
central carbon atom, and hence unable to form an enol tau-
tomer, alkaline hydrolysis has been shown to be more
facile.21–23 The ease of the alkaline hydrolysis of 2 is thus
in accord with the enol tautomer not being readily accessible
in this case. This is in agreement with our spectroscopic data,
which show that only the keto tautomer is present, both in
CDCl3 solution and the solid state.
The alkaline hydrolysis of b-diketones has been reported
previously,21–23 but it was found that b-diketones with at
Inspired by the ease and speed of the alkaline hydrolysis of 2
we found that 4 undergoes a similar reaction to yield the
analogous tris-ketone 6 containing terminal phenyl groups
on each arm (Scheme 1). Although a full investigation of
the reaction mechanism has not been undertaken we propose
that the ease of the alkaline hydrolysis in each of the above
reactions is due to steric interactions between the b-diketone
fragments and the aryl-bound methyl groups, that result in
the predominance of the diketo tautomeric form of these
compounds. Similar sterically hindered b-diketone deriva-
tives have also been found to exist predominantly as their
respective diketo tautomers.16
Figure 1. ORTEP of ligand 4 with ellipsoids shown at the 25% probability
level. The benzoyl groups comprising atoms O3, C26–C32 and O5, C43–49
exhibit minor positional disorder and were modelled with two sites each. For
clarity only one of these is shown.

D. J. Bray et al. / Tetrahedron 63 (2007) 1953–1958
1955
N
NH
N
N
O
N
NH2
N
NHNH2
AcOH
N
N
N
O
O
N
N
N
N
N
HN
N
H
96 %
95 %
5
N
7
8
Scheme 2.
The inability to form the enolate derivatives of 2–4 has pre-
vented an investigation of the self-assembly behaviour of
these tripodal ligands. However, the ketone derivatives, 5
and 6, obtained upon deacylation/debenzoylation of 2 and
4, respectively, are readily functionalised allowing a variety
of new compounds to be prepared. Indeed, there has been an
interest in polyketones as precursors for the divergent ap-
proach to dendritic systems.24 The tris-ketones can be em-
ployed as precursors in the formation of extended tripodal
ligands, in which the functional groups are well separated
from the aryl core. For example, we have prepared the
pyridyl derivatives 7 and 8 by reaction of tris-ketone 5
with 2-picolylamine and 2-hydrazinopyridine, respectively
(Scheme 2). An investigation of the coordination chemistry
of these ligands has been conducted with a variety of transi-
tion-metal ions and the results of this study will be reported
in due course.
signals. Low-resolution electrospray ionization mass spectra
(ESI-MS) were obtained on a Finnigan LCQ-8 spectrometer.
High-resolution electrospray ionization mass spectra
(HRMS-ESI) were obtained on a Finnigan MAT 900 XL
spectrometer. FTIR spectra were determined on a Bio-Rad
FTS-40 spectrometer. Elemental analyses were performed
by the Microanalytical Unit, Australian National University,
Canberra, Australia. Merck Kieselgel 60 silica gel (230–
400 mesh) was used for column chromatography. All com-
mercially available reagents were used as received.
4.1.1. 1,3,5-Tris(bromomethyl)-2,4,6-trimethylbenzene
(1). Compound 1 was prepared by the literature method.14
The 1H NMR data (200 MHz, CDCl3, 300 K): d 2.46
(9H, s, CH3), 4.58 (6H, s, CH2) corresponded to that reported
previously.
4.1.2. 1,3,5-Tris(30-methyl-20,40-pentanedione)-2,4,6-tri-
methylbenzene (2). Acetylacetone (10.01 g, 100 mmol)
was added to a refluxing solution of potassium tert-butoxide
(8.4 g, 75 mmol) in tert-butanol (1250 mL). Trisbromide 1
(10.0 g, 25 mmol) was added in small portions followed
by a catalytic amount of potassium iodide. After 20 h tert-
butanol was removed under reduced pressure and the residue
partitioned between dichloromethane (1250 mL) and water
(500 mL). The organic phase was washed with water
(2ꢀ500 mL) and dried over anhydrous Na2SO4. The di-
chloromethane was removed under vacuum to yield a white
solid. This was recrystallised from ethanol/water (1:4) to
give 2 as fine colourless crystals (11.40 g, 97%), mp 144–
3. Conclusions
Tris-b-diketone derivatives are readily prepared upon treat-
ment of 1,3,5-trimethyl-2,4,6-tris(bromomethyl)benzene with
b-diketones in the presence of base. These compounds
are present as the keto tautomer, both in solution and the
solid state. They do not readily form metal complexes and
upon treatment with base, compounds 2 and 4 undergo a
surprisingly facile hydrolysis, resulting in the formation of
the corresponding tris-ketones 5 and 6 in high yield. Tris-
ketones 5 and 6 are useful building blocks for the construc-
tion of larger tripodal ligands, in which the functional groups
are positioned at a greater distance from the aryl core as
evidenced by the formation of the tris-pyridyl derivatives
7 and 8.
1
145 ꢁC. H NMR (300 MHz, CDCl3, 300 K): d 2.06 (18H,
s, COCH3), 2.19 (9H, s, PhCH3), 3.25 (6H, d, J¼7.4 Hz,
CH2), 3.84 (3H, t, J¼7.4 Hz, COCHCO). 13C NMR
(75.5 MHz, CDCl3, 300 K): d 17.4 (CH3), 29.5 (CH2),
30.6 (CH3), 67.7 (CH), 134.2 (C), 134.7 (C), 204.2
(C]O). MS (ESI): m/z¼479 (M+Na)+. Found (%): C,
71.06; H, 8.09. C27H36O6 requires: C, 71.03; H, 7.95. IR
4. Experimental
4.1. General
(KBr): n(C]O) 1711 cmꢂ1
.
4.1.3. 1,3,5-Tris(20-methyl-10-phenyl-butane-10,30-dione)-
2,4,6-trimethylbenzene (3). Benzoylacetone (3.2 g,
20 mmol) was added to a refluxing solution of potassium
tert-butoxide (1.7 g, 15 mmol) in tert-butanol (250 mL).
Trisbromide 1 (2.00 g, 5 mmol) was then added in small por-
tions followed by a catalytic amount of potassium iodide.
After 20 h of refluxing, tert-butanol was removed under re-
duced pressure and the residue partitioned between dichloro-
methane (150 mL) and water (100 mL). The organic phase
Melting points were measured using a Gallenkamp Electro-
thermal apparatus and are uncorrected. H NMR spectra
1
were recorded on Bruker Avance DPX300 or DPX200 spec-
trometers operating at 300 and 200 MHz, respectively. 13C
NMR spectra were recorded on a Bruker Avance DPX300
spectrometer operating at 75.5 MHz. Chemical shifts are re-
ported in parts per million downfield from tetramethylsilane.
DEPT spectra were used to aid in the assignment of 13C

1956
D. J. Bray et al. / Tetrahedron 63 (2007) 1953–1958
was washed with water (2ꢀ100 mL) and dried over anhy-
drous Na2SO4. The dichloromethane was removed under re-
duced pressure to yield a pale yellow oil. This was purified
via chromatography on silica gel (elution with dichloro-
methane followed by dichloromethane/methanol, 95:5) to
yield 3 (Rf 0.6 in CH2Cl2) as a pale yellow glass (2.67 g,
a suspension of 4 (1.0 g, 1.2 mmol) in a minimum amount of
hot ethanol. The resulting yellow solution was stirred for
5 min until the solution was colourless and then left to
cool. Compound 6 was crystallised from the reaction mix-
1
ture as a white solid (0.57 g, 92%), mp 155–157 ꢁC. H
NMR (300 MHz, CDCl3, 300 K): d 2.34 (9H, s, CH3),
3.16 (12H, s, CH2), 7.47 (6H, m, C6H5), 7.57 (3H, m,
C6H5), 7.98 (6H, m, C6H5). 13C NMR (75.5 MHz, CDCl3,
300 K): d 16.4 (CH3), 25.4 (CH2), 38.5 (CH2), 128.4 (CH),
129.1 (CH), 133.6 (CH), 134.1 (C), 136.8 (C), 137.2 (C),
199.8 (C]O). MS (ESI) m/z¼539 (M+Na)+. Found (%):
C, 83.79; H, 7.13. C36H36O3 requires: C, 83.68; H, 7.03.
1
83%), mp 50–55 ꢁC. H NMR (300 MHz, CDCl3, 300 K):
d 1.97 (9H, s, PhCH3), 2.19 (9H, s, CH3CO), 3.35 (6H, d,
J¼6.4 Hz, CH2), 4.44 (3H, t, J¼6.4 Hz, COCHCO), 7.32–
7.73 (15H, m, Ph). 13C NMR (75.5 MHz, CDCl3, 300 K):
d 17.5 (CH3), 29.3 (CH3), 29.9 (CH3), 63.3 (CH), 128.9
(CH), 129.2 (CH), 134.05 (CH), 134.1 (C), 135.1 (C), 136.9
(C), 197.1 (C]O), 203.6 (C]O). MS (ESI) m/z¼665
(M+Na)+. Found (%): C, 78.09; H, 6.71. C42H42O6 requires:
IR (KBr): n(C]O) 1682 cmꢂ1
.
C, 78.48; H, 6.59. FTIR (KBr): n(C]O) 1717, 1669 cmꢂ1
.
4.1.7. Tris(pyridyl)imine (7). A solution of 2-picolylamine
(0.63 g, 5.8 mmol) in toluene (10 mL) was added to a reflux-
ing solution of tris-ketone 5 (3.00 g, 91 mmol) in toluene
(15 mL). This solution was refluxed using a Dean–Stark
trap for 4 h, before the solvent was removed under vacuum.
This gave tris-imine 7 as a yellow oil (3.5 g, 96%), 1H NMR
(CDCl3, 300 MHz, 300 K): d 2.00 (9H, s, CH3), 2.17 (9H, s,
CH3), 2.59 (6H, m, CH2), 2.98 (6H, m, CH2), 4.67 (6H, s,
NCH2Py), 7.13–7.74 (9H, m, C5H4N), 8.56 (3H, m,
C5H4N). Found (M+H)+ m/z¼601.3994 (HRMS-ESI).
C39H49N6 requires 601.4013.
4.1.4. 1,3,5-Tris(20-methyl-10,30-diphenyl-propane-10,30-
dione)-2,4,6-trimethylbenzene (4). Dibenzoylmethane
(6.3 g, 28 mmol) was added to a refluxing solution of potas-
sium tert-butoxide (2.5 g, 23 mmol) in tert-butanol
(280 mL). Trisbromide 1 (3.0 g, 7.5 mmol) was then added
in small portions followed by a catalytic amount of potas-
sium iodide. After 48 h of refluxing, tert-butanol was re-
moved under reduced pressure and the residue partitioned
between dichloromethane (150 mL) and water (100 mL).
The organic phase was washed with water (6ꢀ100 mL)
and dried over anhydrous Na2SO4. The dichloromethane
was removed under vacuum to yield a pale yellow oil that so-
lidified after two days. This was recrystallised from acetone
to give the title compound as colourless crystals (5.35 g,
86%), mp 208–209 ꢁC. 1H NMR (200 MHz, CDCl3,
300 K): d 1.93 (9H, s, CH3), 3.43 (6H, d, J¼6.3 Hz, CH2),
5.04 (3H, t, J¼6.3 Hz, COCHCO), 7.25–7.71 (30H, m,
Ph). 13C NMR (75.5 MHz, CDCl3, 300 K): d 17.6 (CH3),
30.6 (CH2), 58.7 (C), 129.0 (CH), 129.1 (CH), 133.9 (CH),
134.3 (C), 135.4 (C), 136.4 (C), 196.6 (C]O). MS (ESI)
m/z¼851 (M+Na)+. Found (%): C, 82.54; H, 6.00.
C57H48O6 requires: C, 82.57; H, 5.84. FTIR (KBr): n(C]O)
1699, 1662 cmꢂ1. Crystals of sufficient quality for X-ray
analysis were obtained by recrystallisation of the above
product from ethyl acetate.
4.1.8. Tris(pyridyl)hydrazone (8). A warm solution of 2-
hydrazinopyridine (0.99 g, 9 mmol) in ethanol (5 mL) was
added to a refluxing solution of 5 (1.0 g, 3 mmol) in ethanol
(10 mL). Six drops of glacial acetic acid were added and the
solution was heated at reflux for 35 min before the ethanol
was removed under vacuum, yielding a pale orange solid
1
(1.9 g, 95%), mp 76–77 ꢁC. H NMR (300 MHz, CDCl3,
300 K): d 1.96 (9H, s, CH3), 2.35 (9H, s, CH3), 2.45 (6H,
m, CH2), 2.98 (6H, m, CH2), 6.73 (3H, m, C5H4N), 7.31
(3H, m, C5H4N), 7.60 (3H, m, C5H4N), 8.06 (3H, m,
C5H4N), 8.32 (3H, s, NH). 13C NMR (75.5 MHz, CDCl3,
300 K): d 15.9 (CH3), 16.2 (CH3), 28.2 (CH2), 38.9 (CH2),
108.2 (CH), 115.4 (CH), 138.9 (CH), 146.9 (CH), 157.9
(CH), 132.6 (C), 136.9 (C), 148.8 (C). MS (ESI) m/z¼604
(M+H)+. Found (%): C, 67.32; H, 7.51; N, 19.18.
C36H45N9$21= H2O requires: C, 67.10; H, 7.74; N, 19.57.
4
4.1.5. 1,3,5-Tris(30-oxo-butyl)-2,4,6-trimethylbenzene
(5). A solution of sodium hydroxide (0.26 g, 66 mmol) in
water (10 mL) and methanol (10 mL) was added slowly to
a suspension of 2 (1.0 g, 2.2 mmol) in warm methanol
(20 mL). The resulting solution was stirred for 5 min with-
out further heating and left to cool overnight. Compound 5
was crystallised from the reaction mixture as colourless nee-
4.2. Crystal structure data collection
For both compounds 4 and 5, intensity data were collected at
150(2) K with u scans to approximately 56ꢁ 2q using a
Bruker SMART 1000 diffractometer employing graphite-
monochromated Mo Ka radiation generated from a sealed
1
dles (0.5 g, 70%), mp 143–144 ꢁC. H NMR (200 MHz,
tube (0.71073 A). Data integration and reduction were un-
˚
CDCl3, 300 K): d 2.19 (9H, s, CH3), 2.22 (9H, s, CH3),
2.58 (6H, t, J¼8.3 Hz, CH2), 2.94 (6H, t, J¼8.3 Hz, CH2).
13C NMR (75.5 MHz, CDCl3, 300 K): d 16.1 (CH3), 24.9
(CH3), 30.25 (CH2), 43.5 (CH2), 132.6 (C), 136.4 (C),
208.5 (C]O). MS (ESI) m/z¼329 (MꢂH)ꢂ. Found (%):
C, 75.66; H, 9.28. C21H30O3$1/4H2O requires: C, 75.29;
H, 9.18. FTIR (KBr): n(C]O) 1703 cmꢂ1. Crystals of suffi-
cient quality for X-ray analysis were obtained by slow evap-
oration of an acetone/water solution of the product.
dertaken with SAINT and XPREP25 and subsequent compu-
tations were carried out using WinGX-32 graphical user
interface.26 Multi-scan empirical absorption corrections
were applied to the data using the program SADABS.27
Gaussian absorption corrections were applied using
XPREP.25 Structures were solved by direct methods using
SIR9728 then refined and extended with SHELXL-97.29
Unless otherwise stated, ordered non-hydrogen atoms were
refined anisotropically while partial occupancy non-hydro-
gen atoms were refined isotropically. Hydrogen atoms
attached to carbon atoms were included in idealised posi-
tions and a riding model was used for their refinement.
4.1.6. 1,3,5-Tris(30-oxo-30-phenyl-propyl)-2,4,6-tri-
methylbenzene (6). A solution of sodium hydroxide (0.15 g,
3.6 mmol) in water (5 mL) and ethanol (5 mL) was added to

D. J. Bray et al. / Tetrahedron 63 (2007) 1953–1958
1957
4.2.1. Crystal structure data for compounds 4 and 5.
Compound 4: formula C57H48O6; M¼828.95; monoclinic;
of the data can be obtained, free of charge, on application to
CCDC, 12 Union Road, Cambridge CB2 1EZ, UK (fax: +44
1223 336033 or email: deposit@ccdc.cam.ac.uk).
space group: P21/c(#14); a¼12.2731(6), b¼13.9649(7),
3
c¼26.3234(14) A, b¼102.0650(10)ꢁ; V¼4412.0(4) A ;
Dc¼1.248 g cmꢂ3; Z¼4; crystal size: 0.53 by 0.50 by
0.23 mm; colour: colourless; habit: multi-faced; temper-
˚
˚
Acknowledgements
˚
ature¼150(2) K; l(Mo Ka)¼0.71073 A; m(Mo Ka)¼
We would like to extend our gratitude to the Australian
Research Council for their financial support.
0.080 mmꢂ1; T(SADABS)min,max¼0.917, 1.000; 2qmax
¼
56.64; hkl range: ꢂ16(15), ꢂ18(17), ꢂ34(33); N¼43,322;
Nind¼10,610
(Rmerge¼0.0207);
Nobs¼8469(I>2s(I));
Nvar¼555; residuals R1(F)¼0.0687, wR2(ꢂF32)¼0.1853,
References and notes
˚
GoF(all)¼1.033; Drmin,max¼ꢂ0.536, 0.764 eA
.
1. Bray, D. J.; Clegg, J. K.; Lindoy, L. F.; Schilter, D. Advances in
Inorganic Chemistry; Rudi van Eldik, Ed.; Vol. 59, Chapter 1,
in press.
2. Maverick, A. W.; Klavetter, F. E. Inorg. Chem. 1984, 23, 4129.
3. Clegg, J. K.; Gloe, K.; Hayter, M. J.; Kataeva, O.; Lindoy, L. F.;
Moubaraki, B.; McMurtrie, J. C.; Murray, K. S.; Schilter, D.
Dalton Trans. 2006, 3977.
X
jjFoj ꢂ jFcjj
P
R1 ¼
for Fo > 2sðFoÞ;
jFoj
!
ꢀ
ꢁ
P
1=2
2
w F2o ꢂ F2c
wR2 ¼
for all reflections:
ꢀ
ꢁ
P
2
wF2c
4. Clegg, J. K.; Lindoy, L. F.; McMurtrie, J. C.; Schilter, D. Dalton
Trans. 2006, 3114.
1
5. Hayter, M. J.; Bray, D. J.; Clegg, J. K.; Lindoy, L. F. Synth.
Commun. 2006, 36, 707.
6. Bray, D. J.; Liao, L.-L.; Antonioli, B.; Gloe, K.; Lindoy, L. F.;
McMurtrie, J. C.; Wei, G.; Zhang, X.-Y. Dalton Trans. 2005,
2082.
w ¼ ꢂ
ꢀ
ꢁ
ꢃ; where
2
s2 F2o þ ð0:077PÞ þ3:4339P
ꢀ
ꢁ
F2o þ 2F2c
P ¼
:
3
7. Dalrymple, S. A.; Parvez, M.; Shimizu, G. K. H. Inorg. Chem.
2002, 41, 6986.
Note: the benzoyl groups comprising atoms O3, C26–C32
and O5, C43–49 exhibit minor positional disorder and
were modelled with two sites each. For clarity only one of
these is shown in Figure 1.
8. Bu, X.-H.; Hou, W.-F.; Du, M.; Chen, W.; Zhang, R.-H. Cryst.
Growth Des. 2002, 2, 303.
9. Hartshorn, C. M.; Steel, P. J. Aust. J. Chem. 1995, 48, 1587.
10. Seong, H. R.; Kim, D.-S.; Kim, S.-G.; Choi, H.-J.; Ahn, K. H.
Tetrahedron Lett. 2004, 45, 723.
Compound 5: formula: C21H30O3; M¼330.45; triclinic;
space group: P1ð#2Þ; a¼4.9863(10), b¼11.152(2), c¼
11. Sata, K.; Arai, S.; Yamagishi, T. Tetrahedron Lett. 1999, 40,
5219.
12. Ihm, H.; Yun, S.; Kim, H. G.; Kim, J. K.; Kim, K. S. Org. Lett.
2002, 4, 2897.
13. Amendola, V.; Boiocchi, M.; Fabbrizzi, L.; Palchetti, A. Chem.
Eur. J. 2005, 11, 5648.
14. Van der Made, A. W.; Van der Made, R. H. J. Org. Chem. 1993,
58, 1262.
15. Diez-Barra, E.; Garcia-Martinez, J.; Merino, S.; del Rey, R.;
Rodriguez-Lopez, J.; Sanchez-Verdu, P.; Tejeda, J. J. Org.
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16. Maverick, A. W.; Martone, D. P.; Bradbury, J. R.; Nelson, J. E.
Polyhedron 1989, 8, 1549.
ꢁ
˚
17.205(3) A, a¼81.184(4), b¼84.908(3), g¼88.657(4) ;
3
V¼941.7(3) A ; Dc¼1.165 g cmꢂ3; Z¼2; crystal size:
˚
0.605 by 0.214 by 0.088 mm; colour: colourless; habit:
˚
prism; temperature¼150(2) K; l(Mo Ka)¼0.71073 A;
m(Mo Ka)¼0.076 mmꢂ1
;
T(Gaussian)min,max¼0.9745,
0.9947; 2qmax¼56.74; hkl range: ꢂ6(6), ꢂ14(14),
ꢂ22(22); N¼9354; Nind¼4366 (Rmerge¼0.0399); Nobs
¼
3099(I>2s(I)); Nvar¼223; residuals R1(F)¼0.0479,
wR2(F2)¼ꢂ03.1425, GoF(all)¼1.047; Drmin,max¼ꢂ0.197,
˚
0.269 eA
.
X
17. Emsley, J.; Ma, L. Y. Y.; Bates, P. A.; Motevalli, M.;
Hursthouse, M. B. J. Chem. Soc., Perkin Trans. 2 1989, 527.
18. Dymock, K.; Palenik, G. J. Acta Crystallogr. 1974, B30,
1364.
19. Dormond, A.; Belkalem, B.; Charpin, P.; Lance, M.; Vigner,
D.; Folcher, G.; Guilard, R. Inorg. Chem. 1986, 25, 4785.
20. Charles, R. G. Org. Synth. 1959, 39, 61.
21. Pearson, R. G.; Mayerle, E. A. J. Am. Chem. Soc. 1951, 73, 926.
22. Hauser, C. R.; Swamer, F. W.; Ringler, B. I. J. Am. Chem. Soc.
1948, 70, 4023.
23. Kutz, W. M.; Adkins, H. J. Am. Chem. Soc. 1930, 52, 4391.
24. Diez-Barra, E.; Gonzalez, R.; de la Hoz, A.; Rodriguez, A.;
Sanchez-Verdu, P. Tetrahedron Lett. 1997, 38, 8557; L’abbe,
G.; Haelterman, B.; Dehaen, W. J. Chem. Soc., Perkin Trans.
1 1994, 2203.
jjFoj ꢂ jFcjj
P
R1 ¼
for Fo > 2sðFoÞ;
jFoj
!
ꢀ
ꢁ
P
1=2
2
w F2o ꢂ F2c
wR2 ¼
for all reflections:
ꢀ
ꢁ
P
2
wF2c
1
w ¼ ꢂ
ꢀ
ꢀ
ꢁ
ꢃ; where
2
s2 F2o þ ð0:0805PÞ þ0:0000P
ꢁ
F2o þ 2F2c
P ¼
:
3
Crystallographic data (excluding structure factors) for the
structures in this paper have been deposited with the
Cambridge Crystallographic Data Centre as supplementary
publication nos. CCDC 626206 and CCDC 626207. Copies
25. Bruker. SMART, SAINT and XPREP: Area Detector
Control and Data Integration and Reduction Software;

1958
D. J. Bray et al. / Tetrahedron 63 (2007) 1953–1958
Bruker Analytical X-ray Instruments: Madison, WI,
1995.
26. Farrugia, L. J. J. Appl. Crystallogr. 1999, 32, 837.
28. Altomare, A.; Burla, M. C.; Camalli, M.; Cascarano, G. L.;
Giocavazzo, C.; Guagliardi, A.; Moliterni, A. G. C.; Polidori,
G.; Spagna, S. J. Appl. Crystallogr. 1999, 32, 115.
27. Sheldrick, G. M. SADABS: Empirical Absorption and Correc-
€
29. Sheldrick, G. M. SHELX-97: Programs for Crystal Structure
€
} }
Analysis; University of Gottingen, Institut fur Anorganische
tion Software; University of Gottingen, Institut fur Anorgani-
}
sche Chemie der Universitat: Gottingen, Germany, 1999.
}
€
€
€ €
Chemie der Universitat: Gottingen, Germany, 1998.