Structure correlation study of the beckmann rearrangement: X-ray structural analysis and 13C-13C 1-bond coupling constant study of a range of cyclohexanone oxime derivatives

Article abstract of DOI:10.1071/CH12079

The X-ray structures of a range of oxime derivatives (1 and 4), of cyclohexanone and 4-tert-butylcyclohexanone, where the electron demand of the oxygenated substituent on the oxime nitrogen (OR) is systematically varied were determined. It was established

Full text of DOI:10.1071/CH12079

RESEARCH FRONT
CSIRO PUBLISHING
Aust. J. Chem. 2012, 65, 905–917
Full Paper
http://dx.doi.org/10.1071/CH12079
Structure Correlation Study of the Beckmann
Rearrangement: X-ray Structural Analysis
and 13C 13C 1-Bond Coupling Constant Study
]
of a Range of Cyclohexanone Oxime Derivatives*
A
A
A
Shin Dee Yeoh, Benjamin L. Harris, Tristan J. Simons,
A B
,
and Jonathan M. White
A
School of Chemistry and BIO-21 Institute, University of Melbourne,
Parkville, Vic. 3010, Australia.
B
Corresponding author. Email: whitejm@unimelb.edu.au
The X-ray structures of a range of oxime derivatives (1 and 4), of cyclohexanone and 4-tert-butylcyclohexanone, where the
electron demand of the oxygenated substituent on the oxime nitrogen (OR) is systematically varied were determined. It
was established that as the OR group becomes more electron demanding, then the N–OR bond distance increases,
consistent with the early stages of bond breakage. Concomitant with this structural effect was a noticeable closing up of the
N1–C1–C2 bond angle, consistent with the early stages of migration of the antiperiplanar carbon onto the nitrogen
substituent. These structural effects are consistent with the manifestation of the early stages of the Beckmann
rearrangement in the ground state structures of these oxime derivatives. The carbon–carbon bond distances of the
participating carbons in this rearrangement, however, did not vary in a systematic way with the electron demand of the OR
substituent, suggesting that the structural effects are too small to be detected using X-ray crystallography. However, the
13C–13C 1-bond coupling constants, which are sensitive to the effects of hyperconjugation, were shown to vary in a
systematic way with the electron demand of the OR substituent. Structural effects in the oxime 5 derivatives of
2,2-dimethylcyclohexanone, a substrate that is prone to Beckmann fragmentation rather than Beckmann rearrangement,
were similar but smaller in magnitude.
Manuscript received: 6 February 2012.
Manuscript accepted: 22 March 2012.
Published online: 18 July 2012.
Introduction
for a variety of conformational interconversions have also
been mapped out from analysis of closely related crystal
structures.[10] Several pericyclic and pseudopericyclic frag-
mentations have also been studied using this approach, includ-
ing the retro Diels Alder reaction,[11] and the pericyclic,[12] and
pseudopericyclic[13] cheleotropic carbonyl extrusion reactions.
Kirby and Jones et al. have used this approach to map out the
early stages of unimolecular solvolysis of a variety of
substrates.[14]
Kirby et al. reported the crystal structures of a small number
of oxime derivatives and showed that the early stages of the
Beckmann fragmentation reaction could be discerned from
comparisons of the structural parameters between derivatives
with varying reactivity.[15] The early stages along the reaction
coordinate from the oxime derivative 1 to the intermediate
nitrilium cation 2 (Scheme 1) is achieved by increasing the
electron demand of the OR substituent. Structural effects that
arise with increasing electron demand of the OR substituent
include; (i) lengthening of the N–OR bond distance, (ii) closing
of the anti C–C–N bond angle (a) from 1208 and opening of
the syn C–C–N bond angle (b) from 1208 clearly demonstrating
The early stages of molecular rearrangements are often apparent
in the crystal structures of molecules susceptible to that rear-
rangement. For example, if a particular bond is broken, or if a
particular group migrates during the rearrangement, then
deviations of bond distances and angles from their ‘standard
values’ along the reaction coordinate are often observed. This is
the structure correlation principle,[1] which holds provided the
molecule exists in the ground state, in a geometry which is
similar to the transition state geometry for the reaction. In this
geometry the frontier orbitals whose interactions facilitate the
reaction, can mix in the ground state. Since the original pub-
lications by Burgi and Dunitz, this principle has been applied to
a wide variety of chemical situations, ranging from ligand
addition[2] and dissociation reactions[3] of various metal
complexes, carbonyl insertion reactions in transition metal
carbonyls,[4] nucleophilic addition to metal-coordinated car-
bonyl groups,[5] rearrangements of pentacoordinate metal
complexes,[6] nucleophilic substitution at silicon and
germanium,[7] Berry rearrangements within metal clusters,[8]
and formation of Lewis acid Lewis base complexes.[9] Pathways
*Dedicated to Allan White on the occasion of his 75th birthday.
Journal compilation Ó CSIRO 2012
www.publish.csiro.au/journals/ajc

906
S. D. Yeoh et al.
the molecular movement associated with migration of the
antiperiplanar carbon onto the oxime nitrogen as represented
by the transition state 3. However, systematic effects on the
participating, antiperiplanar carbon–carbon bond were not
apparent from these studies.
Crystals suitable for X-ray analysis for 1b–1e, 1g–1j, 4b, 4d,
4g, 5a–5c, 5e, 5f, and 5h, were obtained by slow evaporation
from dichloromethane or ether. The picrate derivatives 1i and 4i
were found to decompose at room temperature but crystals of 1i
suitable for X-ray analysis were obtained by low temperature
crystallisation.
In this paper we extend the structural studies of Kirby et al. to
encompass cyclohexanone and 4-tert-butylcyclohexanone oxi-
mes having leaving groups (OR) encompassing a wider range of
reactivities attached to the oxime nitrogen, and determined all
the X-ray structures at low temperature. The benefits of carrying
out the structure determinations at low temperature are hoped to
allow us to measure any smaller, systematic effects on the
antiperiplanar carbon–carbon bond involved in the rearrange-
ment. In addition we extended these studies to include, 2,2-
dimethylcyclohexanone oxime derivatives, 5, which have been
reported to undergo Beckmann fragmentation[16] (Scheme 2)
rather than Beckmann rearrangement under certain conditions,
to establish whether increasing the electron demand of the
oxime derivative (-OR) would result in different structural
effects from those shown by the cyclohexanone oxime
derivatives.
The toluene sulphonate ester derivatives 1j and 4j were even
more reactive, and if crystallised at room temperature
Beckmann rearrangement occurred giving the corresponding
protonated lactams 6 or 7 as their toluenesulfonate salts
(Scheme 3). The structure of 6 was verified by single crystal
X-ray diffraction (Fig. 1). Suitable quality crystals of the tosylate
derivative of oxime 1j were eventually grown by crystallisation
from dichloromethane within a desiccator at ꢀ208C.
The thermal ellipsoid plots for selected oxime derivatives 1i,
4b, and 5b are presented in Fig. 2 with atom numbering which is
representative of all derivatives 1b–1e, 1g, 1h, 4b, 4d, 4g,
5a–5c, 5e, and 5h. Unfortunately structural analysis of the
3,5-dinitrobenzoate ester 1e showed that the cyclohexane ring
is disordered due to the occurrence of two cyclohexane chair
conformations at the same molecular site in the crystal.
Results and Discussion
Cyclohexanone oxime (1a) is commercially available, 4-tert-
butylcyclohexanone oxime (4a) was readily prepared from
4-tert-butylcyclohexanone by reaction with hydroxylamine
hydrochloride, and 2,2-dimethylcyclohexanone was prepared
according to a published procedure;[17] purification and con-
version to the corresponding oxime derivative 5a was achieved
under standard conditions. The ester and ether derivatives of
cyclohexanone oxime 1a–1j, 4-tert-butylcyclohexanone oxime
4a–4j, and 2,2-dimethylcyclohexanone 5a–5h prepared for this
study are summarised in Table 1, along with the pKa values of
the corresponding parent acids which give an indication of the
electron demand of the (OR) substituent. The various deriva-
tives were prepared by standard methods.
Table 1. Cyclohexanone oxime derivatives 1a j, 4a j, and 5a h with
]
]
pKa values for the corresponding parent acids
]
OR3
N
R1
R1
R2
δϪ
pKa (ROH)
R3
R1, R2 ¼ H
R1 ¼ H
R1 ¼ Me
R2 ¼ H
OR
R2 ¼ But
OR
-OR
N
N
16
H
1a
1b
1c
1d
1e
1f
4a
4b
4c
4d
4e
4f
5a
5b
5c
5d
5e
5f
α
7.15[18]
3.46[18]
3.43[18]
2.85[19]
2.82[19]
2.17[18]
1.43[19]
0.42[18]
ꢀ2.70[20]
4-NO2C6H4
β
N
ϩ
3-NO2C6H4CO
4-NO2C6H4CO
3,5-(NO2)2C6H3CO
3,4-(NO2)2C6H3CO
2-NO2C6H4CO
2,4-(NO2)2C6H3CO
2,4,6-(NO2)3C6H2
4-CH3C6H4SO2
δϩ
1g
1h
1i
4g
4h
4i
5g
5h
1
3
2
Scheme 1. Beckmann rearrangement of cyclohexanone oxime
1j
4j
derivatives.
OR
N
N
N
C
C
ϩ
Scheme 2. Beckmann fragmentation of 2,2-dimethylcyclohexanone oxime derivatives.

Structure Correlation Study of the Beckman Rearrangement
907
Molecular parameters derived from disordered structures were
deemed unreliable and were not used in this study.
Selected bond distances for the oxime derivatives 1a–1d,
1g–1j, 4b, 4d, 4g, 5a–5c, 5e, 5f, and 5h are presented in Table 2,
while selected bond angles and dihedral angles are presented in
Table 3. These tables also include data for the related oxime
derivatives 8,[21] and 9[22] for which the X-ray structures have
previously been determined at low temperature.
Structural Effects in Cyclohexanone Oxime
SO2
O
N
Derivatives 1a–1j and 4b–4g
OH
ϩ
NH
Inspection of the data contained in Tables 2 and 3 reveals that the
C1–N–O bond angle of the oxime moiety is significantly smaller
than 1208 in all structures with values lying in the range 108.70–
109.818. Although closing of this angle is expected on the basis
of VSEPR[24] it also very likely reflects the preference for the
non-bonded pair to occupy an orbital with greater s character.
The data presented in Table 2, also reveals that the N1–OR bond
distance lengthens as the electron demand of the OR group
increases (as gauged by the pKa value for the parent acid ROH).
This is clearly displayed by the plot of the N1–OR bond distance
vs pKa (ROH), which is presented in Fig. 3 for the cyclohexa-
none oxime derivatives 1a–1j, 4b–4g, and 8–9. Lengthening of
the N1–O1 bond with increasing electron demand can be
considered to represent the early stages of the heterolysis of this
bond and thus also represents the early stages of the Beckmann
rearrangement.
SOϪ3
R
R
1j; R ϭ H
6
; R ϭ H
4j; R ϭ But
7
; R ϭ But
Scheme 3.
O1
N1
C8
C9
O2
C6
C10
S1
O3
C2
C13
C7
In addition to representing the early stages of the Beckmann
rearrangement, the plot in Fig. 3, also represents an application
of the variable oxygen probe,[25] and as such, the slope is
sensitive to the degree of electron donation from both the
antiperiplanar (C2–C1) bond and the synperiplanar (C1–C6)
C5
C11
C12
C3
O4
C4
Fig. 1. Thermal ellipsoid plot of the Beckmann rearrangement product 6.
C6
C5
O1
C11
O3
C12
C1
C4
C13
C7
C8
S
N1
C10
C2
C3
C9
O2
O2
N2
C13
C8
C12
O3
C14
C11
C3
C15
N1
C9
C7
C2
C16
O1
C1
C4
C5
C10
C6
C7
C6
C10
C11
C13
O1
O2
C1
C5
C4
N2
C9
N1
C12
C2
C14
C3
O3
C8
Fig. 2. Thermal ellipsoid plots for oxime derivatives 1j, 4b, and 5b; ellipsoids are at the 20 % probability level.

908
S. D. Yeoh et al.
˚
Table 2. Selected bond distances [A] for oxime derivatives 1a, 4a, 5a, 8, and 9
O
N
N
O
O
CO2H
O
8
9
N1–O1
C1–N1
C1–C2
C6–C1
D (C1–C2/C1–C6)
1a[23]
1b
1c
1d
1g
1h
1i
1.411(2)
1.453(2)
1.442(1)
1.467(2)
1.455(2)
1.482(2)
1.479(2)
1.480(5)
1.445(2)
1.455(1)
1.464(1)
1.416(2)
1.441(1)
1.455(2)
1.465(2)
1.456(1)
1.460(3)
1.433(2)
1.459(2)
1.280(2)
1.273(2)
1.264(2)
1.272(2)
1.278(2)
1.275(3)
1.275(2)
1.280(7)
1.283(2)
1.277(2)
1.274(2)
1.273(2)
1.279(2)
1.277(2)
1.280(2)
1.275(2)
1.284(3)
1.277(2)
1.280(2)
1.500(2)
1.508(2)
1.496(2)
1.508(2)
1.504(2)
1.504(3)
1.501(2)
1.489(7)
1.497(3)
1.500(2)
1.501(2)
1.520(2)
1.522(2)
1.523(2)
1.521(2)
1.522(1)
1.520(3)
1.502(2)
1.509(2)
1.498(2)
1.497(2)
1.487(2)
1.501(3)
1.496(2)
1.479(3)
1.502(2)
1.483(7)
1.491(2)
1.497(2)
1.500(2)
1.510(2)
1.507(2)
1.509(2)
1.506(2)
1.503(2)
1.513(4)
1.502(2)
1.503(2)
0.002
0.011
ꢀ0.009
0.007
0.008
0.025
0.001
0.006
0.006
0.003
0.001
0.010
0.015
0.014
0.015
0.019
0.007
0.000
0.006
1j
4b
4d
4g
5a
5b
5c
5e
5f
5h
8
9
*
bond into the N–OR antibonding orbital. The sC–C–sN–O inter-
action between the anti carbon–carbon bonding orbital and
the N–OR antibonding orbital should be significantly stronger
Associated with bond lengthening of the N1–OR bond
distance as the OR group becomes more electron demanding,
is a systematic closing of the N1–C1–C2 bond angle (Fig. 5).
This structural effect is consistent with the early stages of the
migration of the antiperiplanar carbon (C2) onto the oxime
nitrogen. Closing up of the N1–C1–C2 bond angle, as with
increasing electron demand of the OR group, reflects the
*
that the sC–C–sN–O interaction involving the syn carbon–carbon
bond. It isworthwhile making comparison with the corresponding
plot of the C–OR bond distance vs pKa (ROH) for equatorial
cyclohexane derivatives 10,[26] which measures the strength of
electron donation from the two antiperiplanar ring carbon–carbon
bonds into the C–OR antibonding orbital (Fig. 4). Although there
is slightly more scatter in the plot of N–OR bond distance vs
pKa (ROH) shown in Fig. 3 it is clear that there is a significantly
stronger response of the N–OR bond distance to the electron
demand of the OR substituent in the oxime derivatives 1 (Eqn 2)
than in the cyclohexane derivatives 10 (Eqn 1). There are two
plausible reasons for this: (i) in the oxime derivatives, the
*
*
increasing strength of the sCC–sNOR interaction due to the
improved energy match between the sCC bonding orbital and
*
the -sNOR antibonding orbital. The relationship between the
N1–C1–C2 bond angle and pKa for ROH which is represented
by Eqn 3, shows more scatter than Eqn 2, and likely reflects the
greater susceptibility of bond angles to variation as a result of
differing packing effects associated with each structure.
N1–C1–C2 ½ꢃꢁ ¼ 114:8 þ ð1:5 ꢂ 10ꢀ1Þ pKa ðROHÞ
s
CC–sNOR interactions are occurring across the C¼N double
˚
þ 114:86 R2 ¼ 0:67
bond whose distance is ,1.276 A (Table 2). While in derivatives
ð3Þ
*
10, the sCC–sCOR interactions occur over a C–C single bond
˚
with significantly greater distance of ,1.500 A, there should
therefore be a greater orbital overlap and hence a stronger
interaction in the former case; (ii) in the oximes derivatives, the
N–OR antibonding orbital is located on a more electronegative
Structural Effects in 2,2-Dimethylcyclohexanone Oxime
Derivatives 5a–5h
A plot of N–OR bond distance vs pKa (ROH) for the 2,2-
dimethylcyclohexanone oxime derivatives 5a–5h is presented
in Fig. 6, and also establishes a clear relationship between the
N–OR bond distance and the electron demand of the OR group
(Eqn 4). However when compared to the cyclohexanone oxime
derivatives 1a–1l the response of the N–OR bond distance to the
pKa (ROH) is weaker:
*
atom (N vs C) hence, the sNOR orbital in the oxime derivatives
will have lower energy and interact more strongly with the C–C
bonding orbital.
ꢀ3
10: rC–O ½ ꢁ ¼ 1:479 ꢀ ð2:86 ꢂ 10 Þ pKa ðROHÞ R2 ¼ 0:97
˚
A
ð1Þ
3
1: rN–OR ½ ꢁ ¼ 1:475 ꢀ ð3:80 ꢂ 10 Þ pK ðROHÞ R2 ¼ 0:86
3
2
˚
A
˚
5: rN–OR ½ ꢁ ¼ 1:467 ꢀ ð3:20 ꢂ 10 Þ pK ðROHÞ R ¼ 0:95
A
a
a
ð2Þ
ð4Þ

Structure Correlation Study of the Beckman Rearrangement
909
Table 3. Selected bond angles [8] and dihedral angles [8] for derivatives of oximes 1a, 4a, and 5a
O1–N1–C1
N1–C1–C2
N1–C1–C6
C2–C1–C6
C2–C1–N1–O1
C6–C1–N1–O1
1a
1b
1c
1d
1g
1h
1i
113.4(1)
112.7(1)
108.9(1)
109.7(1)
108.7(1)
109.4(2)
109.1(1)
109.8(4)
109.0(1)
109.7(1)
108.6(1)
113.5(1)
110.2(1)
108.7(1)
109.0(1)
109.54(9)
110.5(2)
111.7(1)
109.3(1)
117.5(2)
116.1(1)
115.1(1)
114.8(2)
115.6(1)
114.0(2)
115.0(1)
115.2(4)
116.1(2)
115.0(1)
115.7(1)
117.4(2)
116.1(1)
116.7(1)
116.0(1)
114.8(1)
115.6(2)
116.1(1)
115.7(1)
125.8(1)
128.3(1)
128.8(1)
129.0(2)
128.9(1)
130.0(2)
127.7(1)
127.5(4)
129.3(2)
129.3(1)
129.1(1)
125.3(2)
126.3(1)
129.1(1)
126.7(1)
127.5(1)
127.7(2)
127.6(1)
128.4(1)
116.7(1)
115.5(1)
116.0(1)
116.2(2)
115.5(1)
115.9(2)
117.3(1)
117.3(4)
114.1(2)
115.9(1)
115.0(1)
117.3(1)
117.6(1)
116.2(1)
117.2(1)
117.66(9)
116.7(2)
116.2(1)
115.8(1)
177.0(2)
176.3(1)
179.6(2)
174.1(2)
176.7(1)
177.3(2)
178.1(1)
177.8(4)
ꢀ177.0(2)
178.5(1)
177.1(1)
178.5(2)
175.9(2)
178.1(1)
ꢀ173.0(1)
ꢀ179.64(8)
176.6(2)
179.1(2)
179.9(2)
1.9(2)
ꢀ1.2(2)
2.1(2)
5.2(2)
ꢀ2.9(2)
1.8(3)
ꢀ1.2(2)
ꢀ3.3(7)
ꢀ1.2(3)
0.0(2)
1j
4b
4d
4g
5a
5b
5c
5e
5f
1.8(2)
2.2(2)
ꢀ2.5(2)
0.0(2)
6.1(2)
ꢀ1.2(2)
ꢀ3.0(2)
1.2(2)
5h
8
9
ꢀ2.2(2)
1.49
1.48
1.47
1.46
1.45
1.44
1.43
1.42
1.41
1.40
118.0
117.5
117.0
116.5
116.0
115.5
115.0
114.5
114.0
y ϭ Ϫ0.0038x ϩ 1.4752
R2 ϭ 0.8639
113.5
0
Ϫ5
5
10
15
20
Ϫ3
2
7
12
17
pKa (ROH)
pKa (ROH)
Fig. 5. Plot of the N1–C1–C2 bond angle [8] vs pKa (ROH) for oxime
derivatives (1a–1j, 4b–4g, and 8, 9).
Fig. 3. Plot of C–OR bond distance vs pKa (ROH) for cyclohexanone
oxime derivatives (1a–1j, 8, 9).
1.47
1.46
1.45
1.44
1.43
1.42
1.41
OR
tBu
OR
10
1
Fig. 4. Application of the variable oxygen probe: comparison between
* *
CC–sCO interactions in derivatives of cyclohexanol 10 and sCC–sNO inter-
actions in the oxime derivatives 1.
s
Plotting the N1–C1–C2 bond angle as a function of the
electron demand of the –OR substituent for the derivatives
5a–5h gives rise to the relationship shown in Fig. 7. This
demonstrates that the bond angle also closes up with increasing
electron demand, however the response of the N1–C1–C2 bond
0
5
10
15
20
pKa (ROH)
Fig. 6. Plot of C–OR bond distance vs pKa (ROH) for cyclohexanone
oxime derivatives (5a–5h).

910
S. D. Yeoh et al.
118.0
117.5
117.0
116.5
116.0
115.5
115.0
114.5
Table 4. 1J (13
C
13C) coupling constants for the oxime
Series 1
Linear (Series 1)
]
derivatives 1a–1i and 4a–4i
All spectra recorded in CDCl3 at 298 K. Coupling constant [Hz]
values are ꢄ0.2 Hz
1J (C1–C2) [Hz]
1J (C1–C6) [Hz]
1a
1b
1c
1d
1e
1f
46.2
44.4
43.3
43.4
43.4
43.0
42.6
42.6
42.3
46.2
44.4
43.3
43.4
43.1
43.1
42.9
42.9
42.7
38.6
37.6
37.9
37.6
38.5
38.8
37.9
38.0
37.6
38.6
37.6
37.9
37.6
37.5
37.7
37.9
37.6
37.5
1g
1h
1i
4a
4b
4c
4d
4e
4f
0
5
10
15
20
pKa (ROH)
Fig. 7. Plot of the N1–C2–C2 bond angle [8] vs pKa (ROH) for cyclohexa-
none oxime derivatives (5a–5h).
4g
4h
4i
angle to the electron demand of the OR group in 5a–5h is weaker
than that observed for the cyclohexanone oxime derivatives
1a–1j, 4b–4g, and 8–9. Although a smaller variation of the
N1–C1–C2 bond angle in 5a–5h might be expected, since
closing up of this angle would be hindered due to steric
interactions between the gem-dimethyl substituents with the
oxime nitrogen, the poor correlation coefficient (Eqn 5) limits
the conclusions that can be made based on this data.
hyperconjugation,[28] which was considered relevant to this
study. The 13C–13C 1-bond coupling constants were determined
for the oxime derivatives 1a–1g and 4a–4h using the 1D
INADEQUATE pulse sequence.[28] The 13C–13C coupling
constants for the antiperiplanar carbon–carbon bond and the
synperiplanar carbon–carbon bond for 1a–1g and 4a–4h are
presented in Table 4. The assignment of these carbons is clear
and unambiguous, and has been reported before for the parent
oxime 1a.
Inspection of the data contained in Table 3 show that the one-
bond 13C–13C coupling constant for C1–C2 (the antiperiplanar
carbon–carbon bond) is approximately 6 Hz larger than the
synperiplanar carbon–carbon bond (C1–C6). This is a feature
of oximes that has been noted previously[29] and has been used in
many cases to assign stereochemistry to oxime derivatives.[30]
The origin of this difference has been suggested to arise from
N1–C1–C2 ½ꢃꢁ ¼ 115:4 þ ð1:2 ꢂ 10ꢀ1Þ pKa ðROHÞ
þ 114:86 R2 ¼ 0:56
ð5Þ
Effects of Varying Electron Demand of (OR)
on the Carbon–Carbon Bond Distances
Examination of the bond distances in Table 2 shows that in the
simple cyclohexanone oxime derivatives 1a–h, 4b, 4d, 4g, 8,
and 9 there is little difference between the antiperiplanar and
synperiplanar C–C bond distances, although in all but one case,
the antiperiplanar bond is slightly longer. For the 2,2-
dimethylcyclohexanone oxime derivatives 5a–5h the anti-
*
a nN–sC–C interaction between the oxime nitrogen lone pair
electrons and the syn carbon–carbon antibonding orbital
(e.g. structure 11 as depicted in Fig. 8),29d which is essentially
an anomeric effect. Interestingly, in the protonated oxime
derivative 12, the anti and syn carbon–carbon coupling con-
stants become very similar; however, the fact that the coupling
constant for the anti carbon–carbon bond decreases upon
protonation, rather than the syn carbon–carbon coupling con-
stant increasing, suggests that the nitrogen lone pair makes a
positive contribution to the coupling constant of the anti carbon–
carbon bond, rather than decreasing the syn carbon–carbon
˚
periplanar C–C bond is on average 0.015 A longer than the
synperiplanar C–C bond. This is to be expected due to the dif-
fering extents of substitution of these two carbon–carbon bonds.
Unfortunately, any effects on the carbon–carbon bond distances
with varying electron demand of the OR substituent are not
observable using X-ray crystallography. The effects are either
too small to be reliably measured by this technique, and/or the
measured carbon–carbon bond distances are too sensitive to
other effects such as crystal packing and thermal libration
effects, which may differ from structure to structure. Thus it was
decided to look at trends of the 13C–13C one-bond coupling
constants in these oxime derivatives as a function of the electron
demand of the OR substituent. It has been demonstrated that
there is a correlation between carbon–carbon bond distances and
the corresponding 13C–13C 1-bond coupling constant, provided
the carbon–carbon bonds being compared are similar with
respect to substitution.[27] Vogel also showed that 13C–13C
one-bond coupling constants are sensitive to the effects of
*
coupling constant. This suggests that nN–sC–C delocalisation
is not the sole reason for this behaviour, but rather it is the result
of several factors which have been discussed in the literature.[30]
The data in Table 3 can be used to construct plots of 13C–13C
coupling constants for the anti and syn carbon–carbon bonds vs
the electron demand of the –OR substituent as quantified by
pKa (ROH). These plots are presented in Figs 9 and 10 respec-
tively. The anti 13C–13C coupling constants (Fig. 9) show a strong
and well defined trend with varying electron demand of the
oxygenated leaving group. The coupling constant clearly
decreases with increasing electron demand of the leaving group.

Structure Correlation Study of the Beckman Rearrangement
911
OH
N
OH
H
ϩ
N
1JCC (trans) ϭ 49.8 Hz JCC (cis) ϭ 41.2 Hz
1JCC (trans) ϭ 42.2 Hz JCC (cis) ϭ 41.9 Hz
1
1
11
12
Fig. 8. 1J (13C–13C) coupling constants for acetone oxime 11 and its protonated derivative 12.
47.0
46.5
46.0
45.5
45.0
44.5
44.0
43.5
43.0
42.5
42.0
41.5
The plot can be used to generate the following equation
(Eqn 6), which relates the coupling constant of the anti carbon–
carbon bond (C1–C2) to the electron demand of the oxygen
substituent as quantified by the pKa value for its parent acid
(ROH):
y ϭ 0.2397x ϩ 42.468
R2 ϭ 0.9719
13
1J ð C–13CÞ ½Hzꢁ ¼ 42:452 þ ð2:25ꢂ10ꢀ1Þ pKa ðROHÞ
R2 ¼ 0:972
ð6Þ
Examination of the plot of the coupling constant for the syn
carbon–carbon bond (C1–C6) with electron demand of the
oxygen substituent (Fig. 10) shows that this coupling constant
appears to vary in a similar way as the anti coupling constant
such that as the electron demand of the oxygen substituent
increases, the syn (C1–C6) coupling constant decreases. How-
ever, the trend is poorly defined with a weaker correlation being
apparent. The larger scatter in the coupling constant data for the
syn carbon–carbon bond (C1–C6) may be due to the fact that the
oxygenated substituent (OR) not only exerts an electronic effect
on this bond, but due to its close proximity, it may also exert a
varying steric effect. The trend line in Fig. 10 is represented
Eqn 7:
0
5
10
15
20
pKa (ROH)
Fig. 9. Plot of J (13C–13C) for the antiperiplanar bond (C1–C2) vs pKa
1
(ROH) for oxime derivatives 1a–1i, and 4a–4i.
39.2
y ϭ 0.0476x ϩ 37.704
39.0
13
1J ð C–13CÞ ½Hzꢁ ¼ 37:651 þ ð7:90 ꢂ 10ꢀ2Þ pKa ðROHÞ
R2 ϭ 0.2669
38.8
R2 ¼ 0:22
ð7Þ
38.6
38.4
38.2
38.0
37.8
37.6
37.4
37.2
Comparison with Eqn 6 derived for the anti carbon–carbon
bond reveals that the coupling constant for the anti bond (C1–
C2) is at least three times more sensitive to the electron demand
of the oxygen substituent than the coupling constant for the syn
bond (C1–C6). This result is consistent with the expected effects
*
of the sC–C–sN–O interaction for both the anti (C1–C2) and syn
(C1–C6) bonds. The anti bond (C1–C2) has more effective
overlap with the N–OR antibonding orbital than the syn bond
(C1–C6), therefore the bond strength and the coupling constant
should be more sensitive to the electron demand of the OR
substituent.
0
5
10
15
20
pKa (ROH)
Fig. 10. Plot of 1J (13C–13C) for the synperiplanar bond (C1–C6) vs pKa
(ROH) for oxime derivatives 1a–1i, and 4a–4i.
Conclusion
This is consistent with the expected bond weakening effects of the
*
s
C–C–sN–O hyperconjugative interaction between the anti
X-ray structural data of cyclohexanone oximes and their deri-
vatives were analysed. These data, which expand upon the early
reports by Kirby et al.[15] show that as the electron demand of the
OR group increases, then the early stages of the Beckmann
rearrangement become clear; the increase of N–OR bond dis-
tance shows the early stages of the heterolysis of this bond, and
the closing up of C2–C1–N bond angle as the anti carbon (C2)
begins to migrate onto the oxime nitrogen. Trends of the anti and
carbon–carbon bond and the N–OR antibonding orbital. Thus as
the electron demand of the OR group increases, the energy of the
N–OR antibonding orbital decreases and becomes a better accep-
tor; this results in a stronger interaction with the anti carbon–
*
carbon bond. Asa resultof the stronger sC–C–sN–O interaction, the
anti 13C–13C bond is weakened, and hence the coupling constant
decreases.

912
S. D. Yeoh et al.
syn carbon–carbon bond distances with increasing electron
demand of the OR group, which might reflect increasing
*
Dc ¼ 1.489 Mg Mꢀ3 m(Mo-Ka) 0.120 mmꢀ1, F(000) ¼ 640,
crystal size 0.40 ꢂ 0.40 ꢂ 0.07 mm. 7173 Reflections measured,
2410 independent reflections (Rint ¼ 0.059), the final R was
0.0422 [I . 2s(I)], and wR(F2) was 0.0899 (all data).
s
CC–sNO hyperconjugation, were however not apparent from
the structural data, although the anti bond (C2–C1) was con-
sistently longer than the syn bond (C1–C6) in all structures.
Evidence for participation of the anti carbon–carbon bond in the
early stages of the Beckmann rearrangement was provided by
analysis of the one-bond 13C–13C coupling constants in the
derivatives 1a–1i and 4a–4l as a function of the electron demand
of the OR substituent. The structural effects in the oxime deri-
vatives 5a–5c, 5e, 5f, and 5h of 2,2-dimethylcyclohexanone,
which undergoes Beckmann fragmentation, were similar to
those observed in the simple cyclohexanone derivatives, but
were smaller in magnitude.
Crystal Data for 1g
C13H14N2O4, M ¼ 262.26, T ¼ 130.0(2) K, l ¼ 0.71073,
orthorhombic, space group Pna21, a ¼ 10.9742(8), b ¼
3
˚
˚
9.7851(7), c ¼ 11.7102(9) A, V ¼ 1257.48(16) A , Z ¼ 4, Dc ¼
1.385 Mg Mꢀ3 m(Mo-Ka) 0.104 mmꢀ1, F(000) ¼ 552, crystal
size 0.25 ꢂ 0.20 ꢂ 0.10 mm. 7481 Reflections measured, 2628
independent reflections (Rint ¼ 0.044), the final R was 0.0337
[I . 2s(I)], and wR(F2) was 0.0795 (all data).
Crystal Data for 1h
Supplementary Material
C13H13N3O6, M ¼ 307.26, T ¼ 130.0(2) K, l ¼ 0.71073
orthorhombic, space group Pccn, a ¼ 25.456(4), b ¼ 9.745(2),
m(Mo-Ka) 0.116 mmꢀ1, F(000) ¼ 1280, crystal size 0.45 ꢂ
0.40 ꢂ 0.30 mm. 13593 Reflections measured, 2497 indepen-
dent reflections (Rint ¼ 0.11), the final R was 0.0485 [I . 2s(I)],
and wR(F2) was 0.1232 (all data).
Crystallographic information files for 1b–1d, 1g–1j, 4b, 4d, 4g,
5a–5c, 5e, 5f, and 5h have been deposited with the Cambridge
Crystallographic Data Centre and assigned CCDC codes
870259–870263 respectively.
3
ꢀ3
˚
˚
c ¼ 11.407(2) A, V ¼ 1127.74(4) A , Z ¼ 8, Dc ¼ 1.442 Mg M
Experimental
Crystallography
Crystal Data for 1i
Crystallographic diffraction data were collected with either a
Bruker SMART Apex CCD detector using Mo Ka radiation
C12H12N4O7, M ¼ 324.26, T ¼ 130.0(2) K, l ¼ 0.71073
monoclinic, space group P21/c, a ¼ 10.693(5), b ¼ 12.549(5),
˚
3
˚
˚
(l ¼ 0.71073 A), or an Oxford Diffraction Sapphire CCD dif-
c ¼ 10.792(5) A, b ¼ 100.225(5)8, V ¼ 1425.1(1) A , Z ¼ 4, Dc ¼
1.511 Mg Mꢀ3 m(Mo-Ka) 0.127 mmꢀ1, F(000) ¼ 672, crystal
size 0.45 ꢂ 0.37 ꢂ 0.27 mm. 7745 Reflections measured, 2722
independent reflections (Rint ¼ 0.040), the final R was 0.0392
[I . 2s(I)], and wR(F2) was 0.1196 (all data).
fractometer using Cu-Ka radiation (graphite crystal mono-
˚
chromator (l ¼ 1.54184 A), or on an Oxford SuperNova
diffractometer using Cu or Mo radiation. Data collected on the
Bruker diffractometer were reduced using the program
SAINT[2] while data collected on the Oxford diffractometer
were reduced using the CrysalisPRO software. The temperature
of the data collections were maintained at 130 K, using an
Oxford Cryostream cooling device. The structures were solved
by direct methods, differences Fourier synthesis, and were
refined on F2 (SHELXL-97).[31] Thermal ellipsoid plots were
generated using the program ORTEP-3[32] integrated within the
WINGX program suite.[33]
Crystal Data for 1j
C13H17NO3S, M ¼ 267.34, T ¼ 130.0(2) K, l ¼ 0.71073
monoclinic, space group Cc, a ¼ 8.780(5), b ¼ 16.387(5), c ¼
3
˚
˚
9.395(5) A, b ¼ 103.956(5)8, V ¼ 1311.8(11) A , Z ¼ 4, Dc ¼
1.354 Mg Mꢀ3 m(Mo-Ka) 0.247 mmꢀ1, F(000) ¼ 568, crystal
size 0.60 ꢂ 0.14 ꢂ 0.06 mm. 3206 Reflections measured, 1701
independent reflections (Rint ¼ 0.035), the final R was 0.0546
[I . 2s(I)], and wR(F2) was 0.1545 (all data).
Crystal Data for 1b
Crystal Data for 4b
C12H14N2O3, M ¼ 234.25, T ¼ 130.0(2) K, l ¼ 1.5418,
monoclinic, space group P21/c, a ¼ 6.9400(1), b ¼ 16.1184(4),
C16H22N2O3, M ¼ 290.36, T ¼ 130.0(2) K, l ¼ 0.71073
3
˚
˚
c ¼ 10.4188(2) A, b ¼ 104.618(2)8, V ¼ 1127.74(4) A , Z ¼ 4,
Dc ¼ 1.380 Mg Mꢀ3, m(Cu-Ka) 0.832 mmꢀ1, F(000) ¼ 496,
crystal size 0.72 ꢂ 0.45 ꢂ 0.18 mm. 3656 Reflections measured,
1708 independent reflections (Rint ¼ 0.028), the final R was
0.0385 [I . 2s(I)], and wR(F2) was 0.1132 (all data).
monoclinic, space group P21/n, a ¼ 5.894(1), b ¼ 21.236(5),
3
˚
˚
c ¼ 12.081(3) A, b ¼ 91.271(4)8, V ¼ 1511.8(6) A , Z ¼ 4, Dc ¼
1.276 Mg Mꢀ3 m(Mo-Ka) 0.088 mmꢀ1, F(000) ¼ 624, crystal
size 0.50 ꢂ 0.45 ꢂ 0.35 mm. 7547 Reflections measured, 2622
independent reflections (Rint ¼ 0.035), the final R was 0.0492
[I . 2s(I)], and wR(F2) was 0.1290 (all data).
Crystal Data for 1c
Crystal Data for 4d
C13H14N2O4, M ¼ 262.26, T ¼ 130.0(2) K, l ¼ 0.71073,
monoclinic, space group P21/c, a ¼ 18.456(5), b ¼ 7.940(2),
C17H22N2O4, M ¼ 318.37, T ¼ 130.0(2) K, l ¼ 0.71073,
3
˚
˚
c ¼ 8.163(2) A, b ¼ 96.298(5)8, V ¼ 1189.0(6) A , Z ¼ 4,
Dc ¼ 1.465 Mg Mꢀ3, m(Mo-Ka) 0.110 mmꢀ1, F(000) ¼ 552,
crystal size 0.45 ꢂ 0.25 ꢂ 0.20 mm. 7157 Reflections measured,
2689 independent reflections (Rint ¼ 0.022), the final R was
0.0427 [I . 2s(I)], and wR(F2) was 0.1131 (all data).
orthorhombic, space group P212121, a ¼ 6.4425(5), b ¼
3
˚
˚
11.9620(9), c ¼ 21.5769(16) A, V ¼ 1662.8(2) A , Z ¼ 4, Dc ¼
1.272 Mg Mꢀ3 m(Mo-Ka) 0.091 mmꢀ1, F(000) ¼ 680, crystal
size 0.50 ꢂ 0.40 ꢂ 0.30 mm. 8812 Reflections measured, 2927
independent reflections (Rint ¼ 0.047), the final R was 0.0321
[I . 2s(I)], and wR(F2) was 0.0703 (all data).
Crystal Data for 1e
Crystal Data for 4g
C13H13N3O6, M ¼ 307.26, T ¼ 130.0(2) K, l ¼ 0.71073,
˚
orthorhombic, space group P212121, a ¼ 6.3148(8), b ¼
C17H22N2O4, M ¼ 318.37, T ¼ 130.0(2) K, l ¼ 1.54184 A
3
˚
˚
9.3102(12), c ¼ 23.318(3) A, V ¼ 1370.9(3) A , Z ¼ 4,
monoclinic, space group P21/n, a ¼ 9.3991(1), b ¼ 15.2220(1),

Structure Correlation Study of the Beckman Rearrangement
913
3
˚
˚
c ¼ 12.5030(1) A, b ¼ 109.367(1)8, V ¼ 1687.62(3) A , Z ¼ 4,
Synthesis
Dc ¼ 1.253 Mg Mꢀ3 m(Cu-Ka) 0.736 mmꢀ1
,
F(000) ¼ 680,
General experimental details have been published
elsewhere.[11f]
crystal size 0.60 ꢂ 0.46 ꢂ 0.30 mm. 8395 Reflections measured,
3313 independent reflections (Rint ¼ 0.035), the final R was
0.0385 [I . 2s(I)], and wR(F2) was 0.1057 (all data).
Cyclohexanone O-4-Nitrophenyl Oxime (1b)
Potassium hydride (74.1 mg, 1.85 mmol) was added to a
solution of oxime 1a (209 mg, 1.85 mmol) in THF (15 mL).
4-Fluoronitrobenzene (261 mg, 0.20 mL, 1.85 mmol) was then
added to this mixture and the reaction stirred for 2 h. The
reaction was quenched by the addition of water, then extracted
into ether (50 mL). The ether layer was washed with water, dried
(MgSO4) and evaporated under reduced pressure to give p-nitro-
phenoxy derivative 1b which was purified by flash column
chromatography (Et2O/light petroleum) to give a light yellow
solid (124 mg, 21 %), which was recrystallised from dichloro-
methane to give colourless blocks, mp ¼ 96.8–97.68C. 1H NMR:
d 8.14 (2H, d, J ¼ 9.2 Hz), 7.21 (2H, d, J ¼ 9.2 Hz), 2.63 (2H, t,
J ¼ 6.2 Hz), 2.34 (2H, t, J ¼ 6.2 Hz), 1.75–1.62 (6H, m), 13C
NMR: d 166.20, 164.34, 141.93, 125.67, 114.14, 32.01, 26.97,
26.28, 25.82, 25.53, IR nmax: 3117, 3071, 3016, 2934, 2856, 164,
1604, 1506, 1485, 1335, 886 cmꢀ1. HRMS (ESI): Calcd
C12H14N2O3 [MþNa]þ 235.10772, found [MþNa]þ
235.10773.
Crystal Data for 5a
C8H15NO, M ¼ 141.21, T ¼ 130.0(2) K, l ¼ 1.54184, mono-
clinic, space group P21/n a ¼ 7.7390(7), b ¼ 10.1658(8), c ¼
3
˚
˚
11.1940(8) A, b ¼ 108.213(9)8, V ¼ 836.55(12) A , Z ¼ 4, Dc ¼
1.121 Mg Mꢀ3 m(Cu-Ka) 0.577 mmꢀ1, F(000) ¼ 312, crystal
size 0.30 ꢂ 0.26 ꢂ 0.03 mm. 2991 Reflections measured, 1503
independent reflections (Rint ¼ 0.028), the final R was 0.0446
[I . 2s(I)], and wR(F2) was 0.1152 (all data).
Crystal Data for 5b
C14H18N2O3, M ¼ 262.30, T ¼ 130.0(2) K, l ¼ 1.5418,
triclinic, space group P-1 a ¼ 7.0117(5), b ¼ 7.3439(5), c ¼
˚
14.553(1) A, a ¼ 76.064(6)8, b ¼ 87.672(6)8, g ¼ 69.413(7)8,
3
V ¼ 680.06(8) A , Z ¼ 2, Dc ¼ 1.281 Mg Mꢀ3 m(Cu-Ka)
˚
0.744 mmꢀ1, F(000) ¼ 280, crystal size 0.32 ꢂ 0.27 ꢂ 0.06 mm.
3704 Reflections measured, 2412 independent reflections
(Rint ¼ 0.019), the final R was 0.0396 [I . 2s(I)], and wR(F2)
was 0.1178 (all data).
Cyclohexanone O-3-Nitrobenzoyl Oxime (1c)
Crystal Data for 5c
Standard procedure for preparation of O-acyl oxime deriva-
tives. Oxime 1a (0.4 g, 3.53 mmol) in dichloromethane (8 mL)
and pyridine (2 mL) was treated with 3-nitrobenzoyl chloride
(689 mg, 3.71 mmol), and stirred for 10 h under an atmosphere
of nitrogen. The reaction was quenched by the addition of water,
and the resulting mixture diluted with dichloromethane (30 mL)
followed by washing with 10 % aqueous NaHCO3 (2 ꢂ 20 mL),
water (1 ꢂ 20 mL), then saturated CuSO4 solution (3 ꢂ 20 mL).
The solvent was dried (MgSO4) and evaporated under reduced
pressure (to afford product 1c as a beige solid (846 mg, 91 %),
which was recrystallised from dichloromethane to give beige
blocks, mp ¼ 109.6–110.78C. 1H NMR: d 8.84 (1H, s), 8.43 (1H,
d, J ¼ 8.0 Hz), 8.38 (1H, d, J ¼ 8.0 Hz), 7.68 (1H, t, J ¼ 8.0 Hz),
2.68 (2H, t, J ¼ 6.4 Hz), 2.47 (2H, t, J ¼ 6.2 Hz) 1.82 (4H, m),
1.66 (2H, m), 13C NMR: d 169.82, 161.30, 147.45, 134.38,
130.37, 129.33, 126.79, 123.45, 31.31, 26.43, 26.06, 25.15,
24.57. IR nmax: 3100, 3086, 2990, 2971, 2937, 2866, 1742,
1638, 1618, 1533, 1440, 1366, 1348, 822 cmꢀ1. HRMS (ESI):
Calcd C13H14N2O4 [MþNa]þ 285.08458, found [MþNa]þ
285.08465.
C15H18N2O4, M ¼ 290.31, T ¼ 130.0(2) K, l ¼ 1.5418,
monoclinic, space group P21/c a ¼ 11.3138(2), b ¼ 12.9150(2),
3
˚
˚
c ¼ 10.7704(2) A,
b ¼ 110.951(2)8,
V ¼ 1469.70(4) A ,
Z ¼ 4, Dc ¼ 1.312 Mg Mꢀ3 m(Cu-Ka) 0.795 mmꢀ1, F(000) ¼
616, crystal size 0.38 ꢂ 0.35 ꢂ 0.26 mm. 5173 Reflections mea-
sured, 2643 independent reflections (Rint ¼ 0.014), the final R
was 0.0376 [I . 2s(I)], and wR(F2) was 0.1048 (all data).
Crystal Data for 5e
C15H17N3O6, M ¼ 335.32, T ¼ 130.0(2) K, l ¼ 1.54184,
orthorhombic, space group Pccn, a ¼ 27.8924(6), b ¼
3
˚
˚
11.7985(3), c ¼ 9.8731(2) A, V ¼ 3249.1(1) A , Z ¼ 8, Dc ¼
1.371 Mg Mꢀ3 m(Cu-Ka) 0.912 mmꢀ1, F(000) ¼ 1408, crystal
size 0.40 ꢂ 0.26 ꢂ 0.09 mm. 7040 Reflections measured, 2928
independent reflections (Rint ¼ 0.020), the final R was 0.0405
[I . 2s(I)], and wR(F2) was 0.1193 (all data).
Crystal Data for 5f
C15H17N3O6, M ¼ 335.32, T ¼ 130.0(2) K, l ¼ 1.54184,
monoclinic, space group P21/n, a ¼ 11.9121(7), b ¼ 7.7814(2),
Cyclohexanone O-4-Nitrobenzoyl Oxime (1d)
3
˚
˚
c ¼ 9.3550(2) A, b ¼ 100.101(5)8, V ¼ 1601.64(13) A , Z ¼ 4,
Following the general procedure described above for the
preparation of 1c, oxime 1a (0.5 g, 4.42 mmol) in dichloro-
methane (5 mL), THF (5 mL) and pyridine (5 mL) was treated
with 4-nitrobenzoyl chloride (861 mg, 4.64 mmol) for 12 h to
afford product 1d as a pale yellow solid (1.0 g, 86 %), which was
recrystallised from dichlromethane to give brown blocks,
mp ¼ 102.1–104.18C. 1H NMR: d 8.29 (2H, d, J ¼ 7.2 Hz),
8.21 (2H, d, J ¼ 7.2 Hz), 2.66 (2H, t, J ¼ 6.3 Hz), 2.46 (2H, t,
J ¼ 6.3 Hz), 1.75 (4H, m), 1.65 (2H, d, J ¼ 5.2 Hz), 13C NMR:
d 170.18, 161.91, 150.08, 134.45, 130.21, 123.18, 31.64, 26.78,
26.34, 25.45, 24.88, IR nmax: 3017, 2970, 2949, 2854, 1737,
1631, 1608, 1525, 1447, 1426, 1366, 854 cmꢀ1. HRMS (ESI):
Calcd C13H14N2O4 [MþNa]þ 285.08458, found [MþNa]þ
285.08467.
Dc ¼ 1.391 Mg Mꢀ3 m(Cu-Ka) 0.925 mmꢀ1
,
F(000) ¼ 704,
crystal size 0.48 ꢂ 0.30 ꢂ 0.18 mm. 10999 Reflections mea-
sured, 3207 independent reflections (Rint ¼ 0.018), the final R
was 0.0345 [I . 2s(I)], and wR(F2) was 0.0935 (all data).
Crystal Data for 5h
C15H17N3O6, M ¼ 335.32, T ¼ 130.0(2) K, l ¼ 1.54184,
monoclinic, space group P21, a ¼ 7.7384(1), b ¼ 10.8085(2),
3
˚
˚
c ¼ 9.3550(2) A, b ¼ 90.465(2)8, V ¼ 782.43(2) A , Z ¼ 2, Dc ¼
1.423 Mg Mꢀ3 m(Cu-Ka) 0.946 mmꢀ1, F(000) ¼ 352, crystal
size 0.20 ꢂ 0.16 ꢂ 0.014 mm. 2648 Reflections measured,
2056 independent reflections (Rint ¼ 0.026), the final R was
0.0325 [I . 2s(I)], and wR(F2) was 0.0768 (all data).

914
S. D. Yeoh et al.
Cyclohexanone O-3,5-Dinitrobenzoyl Oxime (1e)
2,4,6-trinitrofluorobenzene (2.25 g, 9.72 mmol) to afford
product 1i as brown solid (1.78 g, 62 %), which was recrystal-
lised from dichloromethane to give yellow blocks, mp ¼ 104.4–
105.18C. 1H NMR: d 8.71 (2H, s), 2.60 (2H, t, J ¼ 6.2 Hz), 2.18
(2H, t, J ¼ 6.2 Hz), 1.70 (4H, m), 1.61 (2H, d, J ¼ 4.4 Hz),
13C NMR: d 170.18, 150.30, 141.31, 139.96, 123.58, 30.56,
26.57, 25.38, 24.83, IR nmax: 3096, 2944, 2863, 1672, 1611,
1539, 1343, 905 cmꢀ1. HRMS (ESI): Calcd C12H12N4O7
[MþNa]þ 347.05982, found [MþNa]þ 347.05984.
Following the general procedure oxime 1a (0.4 g, 3.53 mmol)
in dichloromethane (8 mL) and pyridine (3 mL) was treated with
3,5-dinitrobenzoyl chloride (856 mg, 3.71 mmol) for 12 h to
afford product 1e as a light brown solid (963 mg, 87 %), which
was recrystallised from dichloromethane to give colourless
1
blocks, mp ¼ 114.8–115.08C. H NMR: d 9.24 (1H, s), 9.16
(2H, s), 2.70 (2H, t, J ¼ 6.4 Hz), 2.50 (2H, t, J ¼ 6.4 Hz), 1.82
(4H, m), 1.71 (2H, m), 13C NMR: d 171.29, 160.07, 148.39,
132.87, 128.99, 122.22, 31.73, 27.08, 26.45, 25.61, 24.97, IR
Cyclohexanone O-4-Toluenesulfonyl Oxime (1j)
n
max: 3104, 2943, 2885, 2858, 1752, 1631, 1598, 1541, 1459,
1447, 1347, 858 cmꢀ1. HRMS (ESI): Calcd C13H13N3O6
4-Toluenesulfonyl chloride (2.53 g, 13.3 mmol) was added to
oxime 1a (1.5 g, 13.3 mmol) in pyridine over 20 min. The
resultant mixture was stirred at ꢀ208C for 3 h, then poured onto
ice (50 g). The white murky mixture was filtered, washed
thoroughly with water and dried to give compound 1j as a white
waxy solid (1.24 g, 35 %). Crystallization from toluene gave the
Beckmann rearrangement product 6 as colourless plates,
[MþNa]þ 330.06966, found [MþNa]þ 330.06979.
Cyclohexanone O-3,4-Dinitrobenzoyl Oxime (1f)
Following the general procedure, oxime 1a (0.30 g,
2.65 mmol) in dichloromethane (7 mL) and pyridine (2 mL)
was treated with 3,4-dinitrobenzoyl chloride (642 mg,
2.78 mmol) for 12 h to afford product 1f as a brown solid
(788 mg, 97 %), which was recrystallised from dichloromethane
to give brown blocks, mp ¼ 84.6–86.28C. 1H NMR: d 8.53 (1H,
d, J ¼ 1.7 Hz,), 8.41 (1H, dd, J ¼ 8.4, 1.7 Hz), 7.99 (1H, d,
J ¼ 8.4 Hz), 2.63 (2H, t, J ¼ 5.4 Hz), 2.43 (2H, t, J ¼ 6.2 Hz)
1.77 (4H, m), 1.65 (2H, d, J ¼ 4.4 Hz), 13C NMR: d 171.11,
160.10, 144.64, 142.01, 134.26, 134.02, 131.96, 125.24, 31.12,
26.36, 26.16, 25.16, 24.48, IR nmax: 3096, 2970, 2941, 2860,
1742, 1631, 1611, 1600, 1539, 1450, 1349, 845 cmꢀ1. HRMS
(ESI): Calcd C13H13N3O6 [MþNa]þ 330.06966, found
[MþNa]þ 330.06980.
1
mp ¼ 79.5–82.08C. H NMR: d 10.21 (1H, bs), 9.62 (1H, bs),
7.67 (2H, d, J ¼ 7.8 Hz), 7.13 (2H, d, J ¼ 7.8 Hz, 3.34 (2H, bs),
2.62 (2H, bs), 2.29 (3H, s), 1.71 (2H, bs), 1.58 (4H, m),
13C NMR: d 182.50, 149.80, 140.48, 128.83, 125.66, 43.78,
32.86, 29.47, 26.64, 21.74, 21.12, IR nmax: 3324, 3069, 2946,
2864, 1653, 1495, 1118, 682 cmꢀ1
.
Crystallisation of the crude 1j from dichloromethane in a
dessicator containing P2O5 at ꢀ108C gave 1j as colourless
1
plates, mp ¼ 101.5–102.88C. H NMR: d 8.14 (2H, d, J ¼ 9.2
Hz), 7.21 (2H, d, J ¼ 9.2 Hz), 2.63 (2H, t, J ¼ 6.2 Hz), 2.34 (2H,
t, J ¼ 6.2 Hz), 1.75–1.62 (6H, m), 13C NMR: d 169.80, 144.61,
132.95, 129.44, 128.65, 31.67, 26.67, 26.53, 25.49, 25.06,
21.61, IR nmax: 3099, 3060, 2993, 2945, 2867, 1648, 1597,
1443, 1362, 1180, 1172, 757 cmꢀ1. HRMS (ESI): Calcd
C13H17NO3S [MþH]þ 268.10019, found [MþH]þ 268.10019.
Cyclohexanone O-2-Nitrobenzoyl Oxime (1g)
Following the general procedure, oxime 1b (0.20 g,
1.77 mmol) in THF (5mL) and pyridine (2mL) was treated with
2-nitrobenzoyl chloride (344 mg, 1.86 mmol) for 12 h to afford
product 1g as a dark brown solid (413 mg, 89 %), which was
recrystallised from dichloromethane to give dark brown blocks,
mp¼ 73.9–75.48C. 1H NMR:d 7.65 (1H, d, J ¼ 8.0 Hz), 7.42(3H,
m), 2.16 (2H, d, J ¼ 6.0 Hz), 2.03 (2H, d, J ¼ 6.0 Hz) 1.4–1.27
(6H, m), 13C NMR: d 169.76, 162.92, 146.97, 132.74, 131.40,
4-tert-Butyl cyclohexanone O-4-Nitrophenyl
Oxime (4b)
Following the general procedure employed for the prepara-
tion of 1b, potassium hydride (23.7 mg, 59.1 mmol) was
added to oxime 4a (100 mg, 0.591 mmol) in THF (15 mL).
4-Fluoronitrobenzene (83.4 mg, 0.063 mL, 5.91 mmol) was then
added to this mixture and stirred for 2 h giving 4b as a light
129.15, 125.85, 123.15, 31.09, 26.15, 26.01, 25.01, 24.35, IR nmax
:
3097, 3075, 2938, 2861, 1750, 1636, 1607, 1577, 1531, 1442,
1354, 855 cmꢀ1. HRMS (ESI): Calcd C13H14N2O4 [MþNa]þ
285.08458, found [MþNa]þ 285.08463.
1
yellow solid (125 mg, 73 %), mp ¼ 103.4–105.18C, H NMR:
d 8.17 (2H, d, J ¼ 9.2 Hz), 7.24 (2H, d, J ¼ 9.2 Hz), 3.46 (1H, d,
J ¼ 12.4 Hz), 2.60 (1H, dd, J ¼ 13.6, 2.6 Hz), 2.06–1.93 (3H, m),
1.31–1.23 (4H, m), 0.88 (9H, m), 13C NMR: d 166.20, 164.30,
141.82, 125.58, 114.07, 47.20, 32.39, 31.73, 27.60, 27.43,
26.52, 26.00, IR nmax: 3055, 3000, 2970, 1655, 1639, 1506,
1366, 1354, 880 cmꢀ1. HRMS (ESI): Calcd C16H23N2O3
[MþH]þ 291.17032, found [MþH]þ 291.17035.
Cyclohexanone O-2,4-Dinitrobenzoyl Oxime (1h)
Following the general procedure, oxime 1a (189 mg,
1.67 mmol) in dichloromethane (5 mL) and pyridine (2 mL)
was treated with 2,4-dinitrobenzoyl chloride (404 mg,
1.75 mmol) for 18 h to afford product 1h as brown solid
(418 mg, 81 %), which was recrystallised from dichloromethane
to give brown plates, mp ¼ 48.4–49.08C. 1H NMR: d 8.71 (1H,
d, J ¼ 2.1 Hz), 8.55 (1H, dd, J ¼ 8.2, 2.1 Hz), 7.9 (1H, d, J ¼ 8.2
Hz), 2.44 (2H, bs), 2.25 (2H, bs), 1.05–1.03 (6H, m), 13C NMR:
d 170.57, 161.92, 148.17, 146.74, 131.65, 130.80, 127.56,
118.74, 31.03, 26.28, 26.10, 25.10, 24.42. IR nmax: 3111,
3090, 3059, 2961, 2933, 2860, 1742, 1636, 1604, 1543, 1531,
1446, 1358, 1349, 827 cmꢀ1. HRMS (ESI): Calcd C13H13N3O6
[MþNa]þ 330.06966, found [MþNa]þ 330.06975.
4-tert-Butyl Cyclohexanone O-3-Nitrobenzoyl
Oxime (4c)
Following general procedure, oxime 4a (0.50 g, 2.95 mmol)
in dichloromethane (7 mL) and pyridine (2 mL) was treated with
3-nitrobenzoyl chloride (576 mg, 3.10 mmol) for 10 h to afford
product 4c as a beige solid (676 mg, 72 %), mp ¼ 109.7–
111.08C. 1H NMR: d 8.57 (1H, bs), 8.20 (1H, dd, J ¼ 7.9,
2.2 Hz), 8.17 (1H, d, J ¼ 7.9 Hz), 7.53 (1H, dd J ¼ 7.9,
7.9 Hz,), 3.21 (1H, d, J ¼ 15.0 Hz), 2.52 (1H, d, J ¼ 13.5 Hz),
2.08–2.01 (1H, m), 1.85 (3H, m), 1.18–1.05 (3H, m), 0.67 (9H,
s), 13C NMR: d 170.13, 161.59, 147.72, 134.65, 130.62, 129.47,
127.02, 123.73, 46.48, 31.89, 31.32, 26.97, 26.94, 26.51, 26.12,
Cyclohexanone O-2,4,6-Trinitrophenyl Oxime (1i)
Oxime 1a (1.0 g, 8.84 mmol) in dichloromethane (10 mL)
was treated with triethylamine (1.85 mL, 1.34 g, 13.3 mmol) and

Structure Correlation Study of the Beckman Rearrangement
915
IR nmax: 3099, 2961, 2866, 1742, 1638, 1615, 1528, 1440, 1367,
1343, 879 cmꢀ1. HRMS (ESI): Calcd C17H22N2O4 [MþNa]þ
341.14718, found [MþNa]þ 341.14733.
147.06, 132.62, 131.34, 129.21, 125.86, 123.09, 46.01, 31.46,
30.82, 26.63, 26.57, 25.90, 25.70, IR nmax: 3085, 2959, 2870,
1749, 1639, 1612, 1579, 1533, 1445, 1366, 1350, 856 cmꢀ1
.
HRMS (ESI): Calcd C17H22N2O4 [MþNa]þ 341.14718, found
[MþNa]þ 341.14722.
4-tert-Butyl Cyclohexanone O-4-Nitrobenzoyl
Oxime (4d)
4-tert-Butyl Cyclohexanone O-2,4-Dinitrobenzoyl
Oxime (4h)
Following general procedure, oxime 4a (0.50 g, 2.95 mmol)
in dichloromethane (7 mL) and pyridine (2 mL) was treated with
4-nitrobenzoyl chloride (576 mg, 3.10 mmol) for 13 h to afford
product 4d as a beige solid (719 mg, 77 %), which was recrys-
tallised from acetonitrile to give beige blocks, mp ¼ 109.9–
111.88C. 1H NMR: d 8.29 (2H, d, J ¼ 8.9), 8.02 (2H, d, J ¼ 8.9),
3.21 (1H, d, J ¼ 13.6 Hz), 2.53 (1H, d, J ¼ 14.0 Hz), 2.05 (1H,
m), 1.85 (3H, m), 1.06–1.15 (3H, m), 0.68 (9H, s), 13C NMR:
d 169.95, 161.63, 149.91, 134.30, 130.04, 123.00, 46.04, 31.80,
31.23, 26.89, 26.86, 26.40, 26.04, IR nmax: 3098, 2959, 2865,
1741, 1638, 1615, 1528, 1440, 1367, 1343, 879 cmꢀ1. HRMS
(ESI): Calcd C17H22N2O4 [MþNa]þ 341.14718, found
[MþNa]þ 341.14735.
Following general procedure, oxime 4a (360 mg, 2.13 mmol)
in dichloromethane (5 mL) and pyridine (2 mL) was treated with
2,4-dinitrobenzoyl chloride (515 mg, 2.23 mmol) for 15 h to
afford 4h as a brown oil (490 mg, 63 %). 1H NMR: d 8.63 (1H,
d, J ¼ 2.2 Hz), 8.45 (1H, dd, J ¼ 8.4, 2.2 Hz), 7.86 (1H, d,
J ¼ 8.4 Hz,), 2.96 (1H, d, J ¼ 12.4 Hz), 2.36 (1H, d, J ¼ 14.0 Hz),
2.03–1.95 (1H, m), 1.86–1.69 (3H, m), 1.16–0.99 (3H, m), 0.67
(9H, s), 13C NMR: d 170.86, 162.33, 148.53, 147.17, 132.13,
131.13, 127.74, 119.14, 46.55, 32.03, 31.27, 27.20, 27.07, 26.54,
26.15, IR nmax: 3107, 2957, 2869, 1748, 1614, 1603, 1535, 1365,
1346, 834 cmꢀ1. HRMS (ESI): Calcd C17H21N3O6 [MþNa]þ
386.13226, found [MþNa]þ 386.13236.
4-tert-Butyl Cyclohexanone O-3,5-Dinitrobenzoyl
Oxime (4e)
4-tert-Butyl Cyclohexanone O-2,4,6-Trinitrophenyl
Oxime (4i)
Following the general procedure, oxime 4a (275 mg,
1.62 mmol) in dichloromethane (8 mL) and pyridine (3 mL)
was treated with 3,5-dinitrobenzoyl chloride (317 mg,
1.71 mmol) for 12 h to afford 4e as a light brown solid
Oxime 4a (1 g, 0.591 mmol) in dichloromethane (10 mL) was
treated with triethylamine (1.23 mL, 896 mg, 8.86 mmol) and
2,4,6-trinitrofluorobenzene (1.5 g, 6.50 mmol) to afford 4i as a
yellowish brown solid (1.16 g, 52 %), mp ¼ 129.1–131.08C.
1H NMR: d 8.73 (2H, s), 3.34 (1H, dd, J ¼ 14.2, 2.0 Hz), 2.37
(1H, d, J ¼ 14.2 Hz), 2.02–1.98 (3H, m), 1.28–1.22 (4H, m),
0.85 (9H, s), 13C NMR: d 170.67, 150.93, 141.96, 140.48,
1
(325 mg, 55 %), mp ¼ 112.2–112.58C. H NMR: d 9.12 (1H,
d, J ¼ 2.0 Hz), 9.04 (2H, bs), 3.33 (1H, d, J ¼ 13.6 Hz), 2.67 (1H,
d, J ¼ 6.2 Hz), 2.21 (1H, m), 2.04 (3H, m), 1.30 (3H, m), 0.83
(9H, m), 13C NMR: d 171.24, 159.91, 148.24, 132.66, 128.84,
122.10, 46.56, 32.04, 31.37, 27.05, 27.02, 26.79, 26.25, IR nmax
3091, 2970, 2870, 1739, 1630, 1546, 1443, 1366, 1359,
:
124.04, 47.13, 32.63, 30.93, 27.79, 27.64, 27.01, 26.60, IR nmax:
3093, 2956, 2869, 1603, 1539, 1345, 914 cmꢀ1. HRMS (ESI):
Calcd C16H20N4O7 [MþH]þ 381.14048, found [MþH]þ
381.14049.
867 cmꢀ1
.
HRMS (ESI): Calcd C17H21N3O6 [MþNa]þ
386.13226, found [MþNa]þ 386.13231.
4-tert-Butyl Cyclohexanone O-3,4-Dinitrobenzoyl
Oxime (4f)
4-tert-Butyl Cyclohexanone O-4-Toluenesulfonyl
Oxime (4j)
Following general procedure, oxime 4a (0.4 g, 2.36 mmol) in
dichloromethane (8 mL) and pyridine (2 mL) was treated with
3,4-dinitrobenzoyl chloride (572 mg, 2.48 mmol) for 11 h to
afford 4f as a brown solid (0.54 g, 63 %), mp ¼ 122.9–
4-Toluenesulfonyl chloride (1.13 g, 5.91 mmol) was added to
oxime 4a (1.0 g, 0.591 mmol) in pyridine, over 20 min. The
resultant mixture was stirred at 0 to ꢀ208C for 3 h. The white
precipitate in the mixture was filtered, washed accordingly, and
dried to successfully give the desired product 4j as white solid
1
124.18C. H NMR: d 8.55 (1H, d, J ¼ 1.5 Hz), 8.39 (1H, dd,
1
J ¼ 8.4, 1.5 Hz), 8.00 (1H, d, J ¼ 8.4 Hz), 3.32 (1H, d, J ¼ 12.8
Hz), 2.75 (1H, d, J ¼ 14.0 Hz), 2.28–2.20 (1H, m), 2.07–2.00
(3H, m), 1.35–1.26 (3H, m), 0.89 (9H, m), 13C NMR: d 171.03,
159.99, 144.61, 141.99, 134.22, 134.00, 131.92, 125.22, 46.46,
40.72, 31.94, 31.30, 26.97, 26.63, 26.14, IR nmax: 3098, 2970,
(1.45 g, 76 %), mp ¼ 97.3–98.68C. H NMR: d 7.83 (2H, d,
J ¼ 9.2 Hz), 7.49 (2H, d, J ¼ 9.2 Hz), 3.17 (1H, d, J ¼ 6.2 Hz),
2.43 (3H, s), 2.35 (1H, d, J ¼ 6.2 Hz), 2.20–1.86 (4H, d, J ¼ 6.2
Hz), 1.31 (1H, m), 1.18–0.7 (2H, m), 0.83 (9H, s), 13C NMR:
d 170.56, 145.24, 133.53, 129.93, 128.88, 46.69, 32.24, 31.30,
29.48, 29.33, 29.17, 29.01, 20.98, IR nmax: 3080, 2951, 2867,
2956, 2870, 1738, 1604, 1542, 1440, 1365, 1350, 844 cmꢀ1
.
HRMS (ESI): Calcd C17H21N3O6 [MþNa]þ 386.13226, found
1641, 1597, 1428, 1368, 1191, 753 cmꢀ1
.
[MþNa]þ 386.13236.
(E)-2,2-Dimethylcyclohexanone Oxime (5a)
4-tert-Butyl Cyclohexanone O-2-Nitrobenzoyl
Oxime (4g)
A solution of hydroxylamine hydrochloride (1.551 g,
24.05 mmol) and sodium acetate (1.312 g, 16.03 mmol) in water
(25 mL) and ethanol (5 mL) was warmed to 608C and crude 2,2-
dimethylcyclohexanone (2.02 g, 16.01 mmol) was added with
swirling. The flask was stirred and ethanol was added until the
solution became homogeneous (approximately 30 mL). The
solution was further stirred at 608C for 3 h, kept at ambient
temperature overnight, then poured onto ice. The mixture was
extracted with ether, concentrated, and crystallised from meth-
anol to yield 5a as white flakes (1.108 g, 7.846 mmol, 49 %),
mp ¼ 93–948C. (lit. mp ¼ 93.5–948C).[34]
To a solution of oxime 4a (0.40 g, 2.36 mmol) in dichlor-
omethane (7 mL) was added pyridine (2 mL).The mixture was
stirred for 30 min before 2-nitrobenzoyl chloride (460 mg,
2.48 mmol) was added at 08C. The reaction was refluxed for
12 h and worked up to afford 4g as a yellow solid (0.58 g, 77 %),
1
mp ¼ 71.9–73.48C. H NMR: d 7.70 (1H, dd, J ¼ 7.0, 7.0 Hz),
7.51 (2H, d, J ¼ 7.0 Hz), 7.46 (1H, m), 2.90 (1H, d, J ¼ 12.0 Hz),
2.35 (1H, bs), 1.93 (1H, m), 1.92 (1H, bs), 1.89–1.59 (1H, m),
1.01–0.89 (3H, m), 0.59 (9H, s), 13C NMR: d 169.54, 162.70,

916
S. D. Yeoh et al.
(E)-2,2-Dimethylcyclohexanone O-4-Nitrophenyl
Oxime (5b)
2-nitrobenzoyl chloride (159 mg, 0.86 mmol) giving 5g
(137 mg, 83 %), which was recrystallized from MeOH to give
colourless needles, mp ¼ 79.6–82.08C. 1H NMR: d 8.00 (1H, d,
J ¼ 8 Hz) 7.60–7.75 (3H, m), 2.53 (2H, m), 1.55–1.66 (6H, m),
1.14 (6H, s, CH3), 13C NMR: d 175.1, 165.0, 147.5, 133.4,
133.4, 131.3, 129.8, 127.9, 123.7, 41.2, 38.7, 26.3, 26.1, 23.4,
21.3, IR nmax: 2938, 1728, 1540 cmꢀ1. HRMS (ESI): Calculated
for C15H19N2Oþ4 [MþH]þ 291.1339, found 291.1340.
Oxime 5a (80 mg, 0.57 mmol) was added to a suspension of
KH (46 mg, 1.15 mmol) in anhydrous THF (20 mL). The solu-
tion was stirred for 30 min at room temperature then cooled to
08C before a solution of 1-fluoro-4-nitrobenzene (120 mg,
0.85 mmol) in anhydrous THF (20 mL) was added and the
reaction was stirred at room temperature for 18 h. The reaction
was quenched with H2O (10 mL), diluted with ether (50 mL),
then washed with H2O (3 ꢂ 100 mL). The organic layer
was dried (MgSO4), filtered, and concentrated to afford 5b as
colourless plates (136 mg, 91 %), mp ¼ 65.1–67.08C. 1H NMR:
d 8.20 (2H, d, J ¼ 7 Hz), 7.26 (2H, d, J ¼ 9 Hz), 1.69 (4H, m),
1.43 1H, s), 1.61 (3H, m), 1.26 (6H, s), 13C NMR: d 171.1, 164.7,
(E)-2,2-Dimethylcyclohexanone O-2,4-Dinitrobenzoyl
Oxime (5h)
By the standard procedure oxime 5a (80 mg, 0.57 mmol) in
dichloromethane (20 mL) and pyridine (2 mL) was treated with
2,4-dinitrobenzoyl chloride (200 mg, 0.87 mmol) to afford 5h
(151 mg, 0.45 mmol, 79 %), which was recrystallized from
MeOH to give colourless plates, mp ¼ 122.8–123.78C.
1H NMR: d 8.88 (1H, d, J ¼ 2.2 Hz), 8.57 (1H, dd, J ¼ 8.4,
2.2 Hz), 7. 89 (1H, d, J ¼ 8.4 Hz), 2.55 (2H, t, J ¼ 12.5 Hz), 1.63
(4H, m), 1.53 (2H, t, J ¼ 11 Hz), 1.07 (6H, s), 13C NMR: d 176.7,
160.3, 148.7, 133.5, 129.2, 122.4, 41.2, 39.1, 26.6, 26.2, 23.8,
21.3, IR nmax: 2934, 1740, 1532 cmꢀ1. HRMS (ESI): Calculated
for C15H17N3Oþ6 [MþH]þ 336.1191, found 336.1189.
141.9, 125.7, 114.2, 41.3, 38.4, 26.7, 26.2, 22.6, 21.5, IR nmax
:
2920, 1587 cmꢀ1. HRMS (ESI): Calculated for C14H19NOþ3
[MþH]þ 263.1390, found 263.1390.
(E)-2,2-Dimethylcyclohexanone O-3-Nitrobenzoyl
Oxime (5c)
By the standard procedure oxime 5a (80 mg, 0.57 mmol) in
dichloromethane (20 mL) and pyridine (2 mL) was treated with
3-nitrobenzoyl chloride (159 mg, 0.86 mmol) to afford 5c
(124 mg, 0.43 mmol, 75 %), which was recrystallized from
MeOH to give colourless plates, mp ¼ 95.8–97.18C. 1H NMR:
d 8.83 (1H, s), 8.42 (1H, m), 8.34 (1H, m), 7.68 (1H, m), 1.5–1.6
(6H, m), 2.69 (2H, m), 1.29 (6H, s), 13C NMR: d 175.8, 162.2,
148.3, 135.2, 131.5, 129.7, 127.4, 124.3, 41.2, 38.9, 26.6, 26.2,
23.6, 21.3, IR nmax: 2954, 1741, 1530 cmꢀ1. HRMS (ESI):
Calculated for C15H19N2Oþ4 [MþH]þ 291.1339, found
291.1339.
References
[1] (a) H. B. Burgi, J. D. Dunitz, E. Shefter, J. Am. Chem. Soc. 1973, 95,
5065. doi:10.1021/JA00796A058
(b) Structure Correlation, ed. H. B. Burgi and J. D. Dunitz, 1994, vol. 1
and 2 (Verlag Chemie: Weinheim).
[2] (a) F. H. Allen, R. Mondalb, N. A. Pitchford, J. A. K. Howard, Helv.
Chim. Acta 2003, 86, 1129. doi:10.1002/HLCA.200390098
(b) T. P. E. A. Derheyde, L. R. Nassimbeni, Acta Cryst. A 1984, 40,
SC104.
[3] V. Ferretti, V. Bertolasi, P. Gilli, G. Gilli, Phys. Chem. Chem. Phys.
(E)-2,2-Dimethylcyclohexanone O-3,4-Dinitrobenzoyl
Oxime (5e)
1999, 1, 2303. doi:10.1039/A900592G
[4] S. A. Jackson, O. Eisenstein, J. D. Martin, A. C. Albeniz, R. H.
Crabtree, Organometallics 1991, 10, 3062. doi:10.1021/
OM00055A019
[5] L.-K. Liu, C.-H. Sun, C.-Z. Yang, Y.-S. Wen, C.-F. Wu, S.-S. Shih,
K.-S. Lin, Organometallics 1992, 11, 972. doi:10.1021/
OM00038A074
By the standard procedure oxime 5a (70 mg, 0.50 mmol) in
CH2Cl2 (20 mL) and pyridine (2 mL) was treated with 3,4-
dinitrobenzoyl chloride (175 mg, 0.76 mmol) to afford 5e
(144 mg, 86 %), which was recrystallized from MeOH to give
1
colourless plates, mp ¼ 129.1–130.78C. H NMR: d 8.55 (1H,
[6] (a) T. Auf der Heyde, Angew. Chem. Int. Ed. Engl. 1994, 33, 823.
doi:10.1002/ANIE.199408231
d, J ¼ 1.7 Hz), 8.42 (1H, dd, J ¼ 8.3, 1.7 Hz), 8.00 (1H, d,
J ¼ 8.3 Hz), 2.67 (2H, t, J ¼ 13 Hz), 1.71 (4H, m), 1.66 (2H, t,
J ¼ 11 Hz), 1.30 (6H, s), 13C NMR: d 176.6, 160.4, 145.1, 142.6,
(b) S. N. Tandura, S. N. Gurkova, A. I. Gusev, N. V. Alekseev, Zh.
Strukt. Khim 1985, 136.
[7] (a) A. R. Bassindale, D. J. Parker, P. G. Taylor, N. Auner,
B. Herrschaft, J. Organomet. Chem. 2003, 667, 66. doi:10.1016/
S0022-328X(02)02130-7
134.3, 126.0, 125.4, 41.2, 39.1, 26.5, 26.2, 23.8, 21.3, IR nmax
:
2956, 1745, 1543 cmꢀ1
.
(E)-2,2-Dimethylcyclohexanone O-3,5-Dinitrobenzoyl
Oxime (5f)
(b) G. Klebe, J. Organomet. Chem. 1985, 293, 147. doi:10.1016/0022-
328X(85)80283-7
[8] A. G. Orpen, I. D. Salter, Organometallics 1991, 10, 111. doi:10.1021/
OM00047A037
[9] (a) D. J. Hankinson, J. Almloef, K. R. Leopold, J. Phys. Chem. 1996,
By the standard procedure oxime 5a (80 mg, 0.57 mmol) in
dichloromethane (20 mL) and pyridine (2 mL) was treated with
3,5-dinitrobenzoyl chloride (201 mg, 0.87 mmol) to afford 5f
(130 mg, 68 %), which was recrystallized from MeOH to give
100, 6904. doi:10.1021/JP960353D
(b) M. A. Dvorak, R. S. Ford, R. D. Suenram, F. J. Lovas, K. R.
Leopold, J. Am. Chem. Soc. 1992, 114, 108. doi:10.1021/
JA00027A015
1
colourless plates, mp ¼ 102.4–103.88C. H NMR: d 9.24 (1H,
dd, J ¼ 2, 2 Hz), 9.15 (2H, d, J ¼ 2 Hz,), 2.70 (2H, m), 1.6–1.8
(6H, m). 1.32 (6H, s), 13C NMR: d 175.6, 164.3, 148.6, 147.2,
133.8, 130.8, 128.0, 119.2, 41.1, 38.7, 26.2, 26.1, 23.4, 21.2,
IR nmax: 2938, 1743, 1542 cmꢀ1. HRMS (ESI): Calculated for
C15H17N3Oþ6 [MþH]þ 336.1190, found 336.1189.
[10] (a) M. Kaftory, D. A. Nugiel, S. E. Biali, Z. Rappoport, J. Am. Chem.
Soc. 1989, 111, 8181. doi:10.1021/JA00203A019
(b) G. A. Sim, Acta Crystallogr. B 1990, 46, 676. doi:10.1107/
S0108768190006802
(c) Z. Rappoport, S. E. Biali, M. Kaftory, J. Am. Chem. Soc. 1990, 112,
7742. doi:10.1021/JA00177A039
[11] (a) D. Birney, T. K. Lim, J. Peng, B. R. Pool, J. M. White, J. Am. Chem.
(E)-2,2-Dimethylcyclohexanone O-2-Nitrobenzoyl
Oxime (5g)
Soc. 2002, 124, 5091. doi:10.1021/JA025634F
By the standard procedure oxime 5a (80 mg, 0.57 mmol)
in CH2Cl2 (20 mL) and pyridine (2 mL) was treated with
(b) B. R. Pool, J. M. White, Org. Lett. 2000, 2, 3505. doi:10.1021/
OL006553W

Structure Correlation Study of the Beckman Rearrangement
917
(c) Y. W. Goh, J. M. White, Aust. J. Chem. 2009, 62, 419. doi:10.1071/
CH09358
(d) Y. W. Goh, B. R. Pool, J. M. White, J. Org. Chem. 2008, 73, 151.
doi:10.1021/JO7018575
(e) Y. W. Goh, J. M. White, Org. Biomol. Chem. 2007, 5, 2354.
doi:10.1039/B707643F
(f) Y. W. Goh, S. M. Danczak, T. K. Lim, J. M. White, J. Org. Chem.
2007, 72, 2929. doi:10.1021/JO0625610
(g) J. Roth-Barton, Y. W. Goh, A. Karnezis, J. M. White, Aust. J.
Chem. 2009, 62, 407. doi:10.1071/CH09349
(h) J. Roth-Barton, J. M. White, Aust. J. Chem. 2009, 62, 1695.
doi:10.1071/CH09349
[25] (a) A. J. Briggs, R. Glenn, P. G. Jones, A. J. Kirby, P. Ramaswamy,
J. Am. Chem. Soc. 1984, 106, 6200. doi:10.1021/JA00333A014
(b) R. D. Amos, N. C. Handy, P. G. Jones, A. J. Kirby, J. K. Parker,
J. M. Percy, M. D. Su, J. Chem. Soc., Perkin Trans. 2 1992, 549.
doi:10.1039/P29920000549
(c) B. R. Pool, J. M. White, P. P. Wolynec, J. Org. Chem. 2000, 65,
7595. doi:10.1021/JO0055638
(d) W. Jackson, J. M. White, Aust. J. Chem. 2008, 61, 956.
doi:10.1071/CH08402
(e) A. J. Green, J. Giordano, J. M. White, Aust. J. Chem. 2000, 53,
285. doi:10.1071/CH99138
[26] J. M. White, M. Spiniello, Org. Biomol. Chem. 2003, 1, 3094.
[27] (a) C. J. Unkefer, R. E. London, T. W. Whaley, G. H. Daub, J. Am.
Chem. Soc. 1983, 105, 733. doi:10.1021/JA00342A010
(b) P. E. Hansen, Annu. Rep. NMR Spectrosc. 1981, 11A, 65.
doi:10.1016/S0066-4103(08)60409-3
[12] Y. W. Goh, J. M. White, Org. Biomol. Chem. 2005, 3, 972.
doi:10.1039/B417538G
[13] H.-X. Wei, C. Zhou, S. Ham, J. M. White, D. M. Birney, Org. Lett.
2004, 6, 4289. doi:10.1021/OL048197D
[14] (a) M. R. Edwards, P. G. Jones, A. J. Kirby, J. Am. Chem. Soc. 1986,
108, 7067. doi:10.1021/JA00282A036
(c) P. E. Hansen, O. K. Poulsen, A. Berg, Org. Magn. Reson.
1979, 12, 43. doi:10.1002/MRC.1270120110
(b) P. G. Jones, A. J. Kirby, J. Am. Chem. Soc. 1984, 106, 6207.
doi:10.1021/JA00333A015
[15] (a) P. G. Jones, M. R. Edwards, A. J. Kirby, Acta Crystallogr. C 1986,
(d) J. L. Marshall, A. M. Ihrig, D. E. Miller, J. Magn. Reson. 1974,
16, 439.
(e) S. Berger, K. P. Zeller, J. Chem. Soc. D 1975, 423.
[28] G. R. Jones, S. Caldarelli, P. Vogel, Helv. Chim. Acta 1997, 80, 59.
doi:10.1002/HLCA.19970800105
[29] (a) R. R. Fraser, R. Capoor, J. W. Bovenkamp, B. V. Lacroix,
J. Pagotto, Can. J. Chem. 1983, 61, 2616. doi:10.1139/V83-448
(b) L. B. Krivdin, G. A. Kalabin, R. N. Nesterenko, B. A. Trofimov,
Tetrahedron Lett. 1984, 25, 4817. doi:10.1016/S0040-4039(01)
81528-8
42, 1230. doi:10.1107/S0108270186092788
(b) M. R. Edwards, A. J. Kirby, P. R. Raithby, P. G. Jones, Acta
Crystallogr. C 1987, 43, 300. doi:10.1107/S0108270187096057
[16] R. Gawley, Beckman Reactions in Organic Reactions, 1988,
pp. 1–420 (Hoboken, NJ).
[17] W. J. Bailey, M. Madoff, J. Am. Chem. Soc. 1954, 76, 2707.
doi:10.1021/JA01639A033
[18] D. R. Lide, CRC Handbook of Chemistry and Physics, 79th Ed., 1998
(c) L. B. Krivdin, G. A. Kalabin, Prog. Nucl. Magn. Reson.
Spectrosc. 1989, 21, 293. doi:10.1016/0079-6565(89)80007-X
(d) F. J. Hoogesteger, D. M. Grove, L. W. Jenneskens, T. J. M. de
Bruin, B. A. J. Jansen, J. Chem. Soc., Perkin Trans. 2 1996, 2327.
doi:10.1039/P29960002327
(CRC Press LLC: Florida).
[19] J. A. Dean, Lange’s Handbook of Chemistry, 14th Ed., 1992 (McGraw-
Hill: New York).
[20] J. F. King, Sulphonic Acids, Esters and Their Derivatives, Chap. 6,
1991, pp. 249–259 (John Wiley & Sons: New York).
[21] F. J. Hoogesteger, L. W. Jenneskins, H. Kooijman, N. Veldman,
A. L. Spek, Tetrahedron 1996, 52, 1773. doi:10.1016/0040-4020(95)
01012-2
[30] N. A. Shcherbina, N. V. Istomina, L. B. Krivdin, Zh. Org. Khim 2005,
41, 1127.
[31] G. M. Sheldrick, Acta Crystallogr. A 2008, 64, 112. doi:10.1107/
S0108767307043930
[22] C. Glidewell, J. N. Low, J. M. S. Skakle, J. L. Wardell, Acta Crystal-
logr. C 2004, 60, 270. doi:10.1107/S0108270104004299
[23] M. Lutz, A. L. Spek, R. Dabiron, C. A. von Walree, L. W. Jenneskens,
Acta Crystallogr. C 2004, 60, 127. doi:10.1107/S0108270103029196
[24] (a) R. J. Gillespie, J. Chem. Educ. 1963, 40, 295. doi:10.1021/
ED040P295
[32] L. J. Farrugia, J. Appl. Cryst. 1997, 30, 565. doi:10.1107/
S0021889897003117
[33] L. J. Farrugia, J. Appl. Cryst. 1999, 32, 837. doi:10.1107/
S0021889899006020
[34] G. N. Barber, R. A. Olofson, J. Org. Chem. 1978, 43, 3015.
doi:10.1021/JO00409A017
(b) R. J. Gillespie, Ed. Quim. 2006, 17, 264.
(c) R. J. Gillespie, Coord. Chem. Rev. 2008, 252, 1315. doi:10.1016/
J.CCR.2007.07.007