A transformation of cyclopropyl carbene: A highly enantioselective three-component reaction via trapping oxonium ylide by imine

Article abstract of DOI:10.1016/j.tet.2016.04.006

A transformation of cyclopropyl carbene generated from 2-cyclopropyl-2-diazoacetate via oxonium ylide was found by trapping the resulting ylide with imine. The asymmetric three-component reaction of cycloproyl diazoacetates, benzenemethanols and imines af

Full text of DOI:10.1016/j.tet.2016.04.006

Tetrahedron 72 (2016) 2929e2934
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A transformation of cyclopropyl carbene: a highly enantioselective
three-component reaction via trapping oxonium ylide by imine
y
y
*
*
Mingfeng Li , Qing Zheng , Weifeng Jin, Shunying Liu , Wenhao Hu
Shanghai Engineering Research Center of Molecular Therapeutics and New Drug Development, Department of Chemistry, School of Chemistry and
Molecular Engineering, East China Normal University, Shanghai, 200062, China
a r t i c l e i n f o
a b s t r a c t
Article history:
A transformation of cyclopropyl carbene generated from 2-cyclopropyl-2-diazoacetate via oxonium ylide
was found by trapping the resulting ylide with imine. The asymmetric three-component reaction of
cycloproyl diazoacetates, benzenemethanols and imines afforded a rapid and efficient method to syn-
thesize complex cyclopropane derivatives with excellent diastereoselectivity and enantioselectivity.
Ó 2016 Elsevier Ltd. All rights reserved.
Received 25 December 2015
Received in revised form 31 March 2016
Accepted 5 April 2016
Available online 6 April 2016
Keywords:
Three-component reaction
Diazocyclopropane
Metal carbene
Oxonium ylide
Asymmetric catalysis
1. Introduction
Cyclopropane is an important structural motif in many natural
products or drugs which have displayed antifungal, antibacterial,
antiviral, or some enzyme inhibition activities (Scheme 1).1 For
a long time, the chemistry of cyclopropane derivatives is amazingly
diversified and continues to fascinate scientists from a broad range
of backgrounds, especially for researchers with interests in natural
product and/or medicinal chemistry.2 Several excellent methods
have been developed for the construction of cyclopropane,3 such as
SimmonseSmith cyclopropanation,3b Michael addition-initiated
ring-closure reactions (MIRCs),3c,3d and asymmetric cyclo-
propanation of olefins with metallocarbenes.3f Recently, Zhang and
co-workers successfully developed a highly diastereo- and enan-
tioselective intramolecular cyclopropanation of 1,6-enynes through
gold (I)-catalyzed alkyne oxidation with a chiral phophoramidite
ligand.4 However, an alternative strategy, introducing an existing
cyclopropane scaffold to construct complex compounds is rarely
explored.5 A complementary approach that enables fast access to
complex cyclopropane derivatives from a cyclopropane scaffold is
still in great demand.
Scheme 1. Cyclopropane motif in Star drug molecules.
Diazo cyclopropanes provide such a possible approach to rapid
synthesize complex cyclopropane derivatives due to their active
reactivity.6 Even though diazo chemistry has shown a wonderful
scenario in modern organic synthesis,7 the multi-component re-
action of diazo cyclopropanes via cyclopropyl carbene to offer
complex molecules containing cyclopropyl scaffolds has not yet
been reported. It is well known that cyclopropyl carbene which
generated from the decomposition of diazo cyclopropane nearly
quantitatively undergoes a rearrangement to give cyclobutene be-
cause of its steric effect and electronic factor.8 For an example, Tang
and co-workers reported a very fast transition-metal-catalyzed
rearrangement reaction of cyclopropyl carbene which in situ gen-
erated from diazo cyclopropanes at room temperature via a highly
* Corresponding authors. Tel./fax: þ86 21 62221237; e-mail addresses: syliu@sist.
ecnu.edu.cn (S. Liu), whu@chem.ecnu.edu.cn (W. Hu).
y
M.L. and Q.Z. equally contributed to the work.
http://dx.doi.org/10.1016/j.tet.2016.04.006
0040-4020/Ó 2016 Elsevier Ltd. All rights reserved.

2930
M. Li et al. / Tetrahedron 72 (2016) 2929e2934
selective ring expansion to synthesize poly-substituted cyclo-
butenes in nearly quantitative yields (Scheme 2).9 Here, we re-
ported a new transformation of cyclopropyl carbene via an
oxonium ylide intermediate with alcohol, and the active ylide was
trapped by chiral phosphoric acid (PPA) activated imines to afford
polyfunctional cyclopropane derivatives with high diastereo- and
enantioselectivity.
of cyclopropyl carbene generated from the metal-associated diazo
cyclopropane via oxonium ylide was promoted even though the
competitive rearrangement processes were not completely sus-
pended. It is well known that imines can be activated by PPA,14 and
then the effect of PPA on the yield of three-component product was
initially investigated by PPA 10a. To our delight, the reaction led to
4a in an increased yield of 25% and with >95:5 d.r. and 98% ee by
using chiral PPA (R)-10a (Table 1, entry 5). With these preliminary
results, we focused on screening a range of chiral PPAs to get
a further improved yield and asymmetric version of this reaction
(Table 1, entries 6e10). The evaluation of various PPAs revealed that
other chiral PPA obviously decreased the enantioselectivity with no
conspicuous electronic effect albeit a slightly increased yield (en-
tries 6e9). Finally, (R)-10a bearing bulky triisopropylphenyl (TRIP)
substitution was optimal to use for the model reaction. When (S)-
10a was used to give the corresponding product with a reversed ee
value of ꢀ96% comparing to that was achieved by (R)-10a (Table 1,
entry 10), which implied that the enantioselectivity of this trans-
formation was deduced by the chiral catalyst. Decreasing the
amount of diazo compound 1a to one equivalent has no notable
influence on the yield of 4a (Table 1, entry 11). Therefore, the
amount ratio of 1a:2a:3a was fixed as 1:1:1 for the next study. In all
the above cases, the ring expansion product substituted cyclo-
butene 5a was still observed as main by-product accompanying
with a trace amount of OeH insertion by-product 6.
Scheme 2. Transition-metal-catalyzed selective ring expansion of diazo cyclopropanes
by Tang and co-workers.
We have focused for a long term on discovering new three-
component reactions by trapping an oxonium ylide in situ gener-
ated from a diazo compound and an alcohol in the presence of
rhodium acetate with electrophiles, such as imines,10 ketone or
aldehyde,11 -unsaturated ketoesters12 and azodicarboxylate13 to
a,b
rapidly construct multifunctional complex molecules. Thus we
reasonably envision that cycloproyl carbene may react with alcohol
to form oxonium ylide and the classic rearrangement pathway
(Scheme 3, path A) will be suppressed or changed. The resulting
ylide intermediate is further trapped by imines or other electro-
philes (Scheme 3, path C) to develop a three-component method,
which will provide a rapid and convenient access to the construc-
tion of complex molecules containing cyclopropane moieties. Ob-
viously, another mainly competitive transformation arises from the
proton transfer of oxonium ylide which leads to an OeH insertion
molecule as side product (Scheme 3, path B).
Table 1
Screening of metal catalysts and chiral PPAs
Entry MLn
T (ꢁC) 10
4a: 5a Yield (%)a 4a d.r.
(syn/anti)b 4a (%)c 4a
ee
1
2
3
4
5
6
7
8
9
10
[Pd(allyl)Cl]2 25 No
0
0
Trace
Trace
d
d
d
d
d
Cu(hfac)2
Rh2(OAc)4
Rh2(OAc)4
Rh2(OAc)4
Rh2(OAc)4
Rh2(OAc)4
Rh2(OAc)4
Rh2(OAc)4
Rh2(OAc)4
25 No
25 No
ꢀ10 No
d
1:5.7 15
1:4.3 19
d
>95:5
>95:5
>95:5
>95:5
>95:5
>95:5
>95:5
>95:5
Scheme 3. Trapping of onium intermediate derived from alcohol and cyclopropyl
carbene with imine.
ꢀ10 (R)-10a 1:3.0 25
ꢀ10 (R)-10b 1:2.3 30
ꢀ10 (R)-10c 1:2.0 33
ꢀ10 (R)-10d 1:2.0 33
ꢀ10 (R)-10e 1:2.1 32
ꢀ10 (S)-10a 1:2.1 32
ꢀ10 (R)-10a 1:3.2 24
98
61
60
35
60
2. Result and discussion
ꢀ96
11d Rh2(OAc)4
98
The initial investigation was commenced by examining the two-
component reaction of cyclopropane diazo compound 1a and
benzyl alcohol 2a using the commonly used catalyst rhodium ac-
etate for cyclopropyl carbene generation. A considerable amount of
OeH insertion product was observed together with the ring ex-
pansion product 5a as expected. Encouraged by the observed OeH
insertion product, we surveyed a model reaction with diazo cy-
clopropane 1a, benzyl alcohol 2a and 2-anisidine benzaldehyde
imine 3a with various metal catalysts at room temperature (Table 1,
entries 1e3). Only trace three-component product 4a was observed
when [Pd(allyl)Cl]2 or Cu(hfac)2 was respectively used. Gratifyingly,
Rh2(OAc)4 gave the three-component product 4a in 15% yield (Table
1, entry 3). When the reaction temperature was decreased to
ꢀ10 ꢁC, the yield of 4a was increased to 19% and with >95:5 d.r.
(Table 1, entry 4). These results indicated that a new transformation
Reaction conditions: MLn/10/1a/2a/3a¼0.01/0.05/2.0/1.1/1.0, 1a in DCM was added
ꢀ
to a solution of 2a, 3a, 10, MLn, 4 A MS in DCM under an argon atmosphere over 1 h
via a syringe pump and stirred for another 1 h.
a
Isolated yield of 4a.
b
Determined by 1H NMR of the unpurified reaction mixture.
c
Determined by chiral HPLC analysis.
1a/2a/3a[1.0/1.0/1.0. PMP: p-methoxyl phenyl; Bn: benzyl; MS: molecular
d
sieve. DCM:dichloromethane.
According to our previous product structure of three-
component reaction, which the oxonium ylide formed by aryl10f
with benzyl alcohol trapped by chiral PPA-activated imines, we
speculated that the absolute configuration of three-component
reaction product syn-4a was (2R, 3S) by analysis.

M. Li et al. / Tetrahedron 72 (2016) 2929e2934
2931
The effects of solvent and reaction temperature on the reaction
chemoselectivity were then investigated (Table 2). The results
revealed that the three-component reaction proceeded better in
CHCl3 than in DCM, DCE, toluene and hexane at ꢀ10 ꢁC (Table 2,
entries 1e5) to give the ratio of 4a:5a as 1:2.8 (which determined
by the integrity of 1H NMR spectra) with excellent 98:2 d.r. and 98%
ee of 4a (Table 2, entry 4). When the temperature was further de-
creased to ꢀ40 ꢁC and standing the reaction mixture for another
3 h, the proportion of 4a:5a was improved to 1:2.3 without the
erosion of diastereoselectivity and enantioselectivity (Table 2, entry
6). The yield of 4a was slightly decreased with a further decline in
the temperature (Table 2, entry 7). Increasing the equivalent of
benzyl alcohol or imine was ineffective to improve the yield of 4a
(Table 2, entries 8e9). The increased amount of (R)-10a had also no
obvious effect on the ee and d.r. values of 4a (Table 2, entry 10). The
optimal conditions were finally established as follows: 1 (1 equiv), 2
(1 equiv) and 3 (1 equiv) with 5 mol % of chiral PPA (R)-10a in CHCl3
at ꢀ40 ꢁC with 4 A MS as the addictive (Table 2, entry 6).
ꢀ
Under the optimized reaction conditions, the substrate scope
was evaluated with various benzenemethanols and imines, and the
results are summarized in Table 3. In most cases, the reaction
proceeded smoothly to give the desired product 4 in a considerable
yield (the chemoselectivity of 4:5 is up to 1:2) and with high dia-
stereoselectivity (up to 95:5 d.r.) and excellent enantioselectivity of
4 (up to 99% ee). The electronic nature of phenyl group in benzyl
alcohol has little effect on the yield of the product 4 (Table 3, entries
1e4). However, possibly due to the steric hindrance, ortho-
methoxyl substituent (Table 3, entry 5) led to the slightly decline of
the yield to 23% remaining excellent d.r. (>95:5) and ee value (97%).
The 9-anthracenyl methanol also led to a mere yield of 19% by the
effect of steric hindrance (Table 3, entry 6). Both H2O and ethanol
only afford substituted cyclobutene 5a as main by-product which
implied that the current synthetic scope was a little limited.
The electronic nature of imines have little effect on the yield of the
desired product 4, which demonstrated good to excellent stereo-
selective control (Table 3, entries 7e9), except for the p-NO2
substituted electron-withdrawing imine (Table 3, entry 10) which
resulted in a decreasing enantioselectivity to 55% ee The reaction
with the o-NO2 substituted imine (Table 3, entry 10) was explored,
giving the corresponding product in a similar yield (30%) and with an
excellent ee (97%, the syn diastereomer) albeit a low d.r (62:38), the
anti diastereomer of which was also obtained with a high ee value
(92% ee). p-Br substituent in Ar3 of imine obviously affected the ee of
product, which made the ee drop dramatically to 25% accompanying
with a decrease in d.r. ratio (80:20, Table 3, entry 11). Substitutions on
the cyclopropyl ring in diazo 1, ethyl-exo-(bicyclo[4.1.0]hept-7-yl)
diazoacetate 1b as an example, also provides the same result as the
most cases in 29% yield with >95:5 dr and 92% ee (Table 3, entry 12).
The synthetic application of the three-component products
were illustrated by an already reported base-promoted intra-
Table 2
Optimization of the reaction conditionsa
Entry Solvent T (ꢁC) 4a: 5a Yield (%) 4a d.r. (syn/anti) b4a ee (%) c4a
1
2
3
4
5
6
7
DCM
Toluene
DCE
CHCl3
Hexane
CHCl3
CHCl3
CHCl3
CHCl3
CHCl3
ꢀ10 1:3.0
ꢀ10 1:5.0
ꢀ10 1:7.5
ꢀ10 1:2.8
ꢀ10 1:4.1
ꢀ40a 1:2.3
ꢀ60a 1:3.4
ꢀ40a 1:3.2
ꢀ40a 1:2.3
ꢀ40a 1:2.4
25
17
12
26
20
30
23
98:2
91:9
97:3
98:2
97:3
98:2
86:14
98:2
98:2
98:2
98
94
98
98
98
98
98
98
98
98
8d
9e
10f
Reaction conditions: Rh2(OAc)4/(R)-10a/1a/2a/3a¼0.01/0.05/1.0/1.0/1.0, 1a in sol-
ꢀ
vent was added to a solution of 2a, 3a, Rh2(OAc)4, (R)-10a, 4 A MS in solvent under
an argon atmosphere over 1 h via a syringe pump.
b, c As performed in Table 1.
a
Stirred for another 3 h.
2 equiv. of benzyl alcohol.
2 equiv. of imine.
(R)-10a (10%). DCE: 1, 2-dichloroethane.
d
e
molecular ring closure15 to yield
b-lactam
6
with lithium
f
Table 3
Substrate scope of syn-selective enantioselective three-component reaction of 1, 2, and 3
Entry
1
Ar1
Ar2
Ar3
4:5b
Yield (%)a of 4
d.r.(syn/anti)b of 4
ee (%)c of syn-4
1
2
3
4
5
6
7
8
1a
1a
1a
1a
1a
1a
1a
1a
1a
1a
1a
1b
Ph
p-MeOPh
p-BrPh
m-MeOPh
o-MeOPh
9-Anthracenyl
Ph
Ph
Ph
Ph
Ph
Ph
Ph
Ph
Ph
Ph
Ph
Ph
p-ClPh
p-MePh
p-NO2Ph
o-NO2Ph
Ph
PMP
PMP
PMP
PMP
PMP
PMP
PMP
PMP
PMP
PMP
p-BrPh
PMP
1:2.3
1:2.3
1:2.3
1:2.3
1:3.3
1:4.2
1:2.3
1:2.0
1:2.1
1:2.3
1:2.6
1:2.5
30 (4a)
30 (4b)
30 (4c)
30 (4d)
23 (4e)
19 (4f)
30 (4g)
33 (4h)
32 (4i)
30 (4j)
27 (4k)
29 (4l)
>95:5
>95:5
>95:5
>95:5
>95:5
>95:5
>95:5
>95:5
>95:5
62:38
80:20
>95:5
98
88
99
94
97
98
90
96
55
97d
25
92
9
10
11
12
PMP
ꢀ
Reaction conditions: Rh2(OAc)4/(R)-10a/1a/2a/3a¼0.01/0.05/1.0/1.0/1.0, 1 in CHCl3 was added to a solution of 2, 3, Rh2(OAc)4, (R)-10a, 4 A MS in CHCl3 under an argon at-
mosphere over 1 h via a syringe pump and stirred for another 3 h.
b, c As performed in Table 1.
a
Isolated yield.
The ee value of the minor anti diastereomer is 92%.
d

2932
M. Li et al. / Tetrahedron 72 (2016) 2929e2934
ꢁ
ꢀ
bis(trimethylsilyl)amide (LHMDS) in dry THF (Scheme 4) with
a high yield of 93% remaining an unchanged ee value of 92%.
4 A molecular sieve (150 mg) in 3 mL of DCM were stirred at ꢀ40 C
for 20 min, and then the mixture of diazo compound (0.2 mmol) in
2 mL of DCM was introduced to the mixture over 1 h via a syringe
pump. Stir another 3 h until the diazo compound decomposed
completely. After completion of the reaction (monitored by TLC),
the mixture was filtered and the filtrate was concentrated to give
a residue which was subjected to 1H NMR spectroscopy analysis for
the determination of d.r. and HPLC for the ee values. The crude
product was further purified by column chromatography on silica
gel (EtOAc/light petroleum ether¼1:200e1:50) to get the final
product 4.
Scheme 4. Synthetic application of the three-component product.
4.2.1. Benzyl-2-(benzyloxy)-2-cyclopropyl-3-((4-methoxyphenyl)
amino)-3-phenylpropanoate (4a) (2R,3S)-syn-4a. 98% ee 1H NMR
3. Conclusion
(400 MHz, CDCl3)
d 7.39e7.24 (m, 10H), 7.24e7.04 (m, 5H), 6.64 (d,
J¼8.8 Hz, 2H), 6.51 (d, J¼8.8 Hz, 2H), 4.83 (m, 5H), 4.62 (s, 1H), 3.65
In conclusion, we have discovered a new transformation of
cyclopropyl carbene derived from cyclopropane diazo compounds
via an oxonium ylide which trapped by imines with high diaster-
eoselectivity (up to 95:5 d.r.) and excellent enantioselectivity (up to
99% ee). It is the first time to successfully achieve the efficient ylide-
trapping process from cyclopropyl carbenes even though the
competitive ring expansion of cyclopropyl carbenes is not com-
pletely suppressed. The developed method provides a mildly al-
ternative approach to rapid access to complex cyclopropane
derivatives. The further research of using this strategy in the re-
spect of high transformation ratio and efficient synthesis of cyclo-
propane derivatives compounds is currently underway in our lab.
(s, 3H), 1.54e1.42 (m, 1H), 1.02 (m, 1H), 0.74 (m, 1H), 0.57e0.40 (m,
2H); 13C NMR (100 MHz, CDCl3)
d 170.22, 151.95, 141.12, 139.36,
139.28,135.03, 129.02,128.55,128.50,128.33,128.24, 127.69,127.54,
127.41, 127.33, 115.06, 114.75, 86.73, 67.53, 66.67, 64.66, 55.68, 15.21,
5.03, 1.61; HRMS (ESI) calcd for C33H33NNaO4 [MþNa]þ¼530.2307
found 530.2323; HPLC (Chiral ODeH,
propanol¼80:1, flow rate¼1.0 mL/min), tmajor¼9.14 min,
tminor¼7.49 min.
l
¼254 nm, hexane/2-
4.2.2. Benzyl-2-cyclopropyl-2-((4-methoxybenzyl)oxy)-3-((4-
methoxyphenyl)amino)-3-phenylpropanoate(4b)
(2R,3S)-syn-
4b. 88% ee 1H NMR (400 MHz, CDCl3)
d
7.38e7.23 (m, 7H), 7.18 (m,
3H), 7.10 (s, 2H), 6.84 (d, J¼7.9 Hz, 2H), 6.63 (d, J¼8.2 Hz, 2H), 6.50
(d, J¼8.2 Hz, 2H), 4.80 (m, 5H), 4.68e4.16 (m, 1H), 3.80 (s, 3H), 3.63
4. Experimental section
(s, 3H), 1.47 (s, 1H), 1.02 (m, 1H), 0.72 (s, 1H), 0.58e0.39 (m, 2H); 13
C
4.1. General information and materials
NMR (100 MHz, CDCl3)
d 170.26, 158.96, 151.92, 141.12, 139.40,
135.03, 131.36, 129.04, 129.01, 128.55, 128.47, 128.30, 127.63, 127.34,
115.04, 114.72, 113.60, 86.57, 67.17, 66.62, 64.65, 55.6, 55.24, 15.23,
4.99, 1.60; HRMS (ESI) calcd for C34H35NNaO5 [MþNa]þ¼560.2413
All chemicals were purchased from commercial sources without
further purification. All 1H NMR (400 MHz) and 13C NMR (100 MHz)
spectra were recorded on Brucker spectrometers in CDCl3. Tetra-
found 560.2397; HPLC (Chiral ODeH,
l
¼254 nm, hexane/alco-
methylsilane (TMS) served as an internal standard (
d
¼0) for 1H
hol¼200:1,
flow
tminor¼50.94 min.
rate¼1.0
mL/min), tmajor¼28.22 min,
NMR, and CDCl3 was used as internal standard (
d
¼77.0) for 13C
NMR. Chemical shifts are reported in parts per million as follows:
chemical shift, multiplicity (s¼singlet, d¼doublet, t¼triplet,
q¼quartet, m¼multiplet, br¼broad). HRMS spectra were recorded
on Bruker micrOTOF-II mass spectrometer. HPLC analysis was
performed on Dalian Elite (UV230þ UV/Vis Detector and P230P
High Pressure Pump). Chiralpak IC, ODeH chiral columns were
purchased from Daicel Chemical Industries, LTD. Melting points
were uncorrected. The racemic standards used in HPLC studies
were prepared according to the general procedure by using racemic
BINOL-derivatived phosphoric acid catalysts. Yields for all com-
pounds were combined yields for all isomers unless otherwise
indicated.
4.2.3. Benzyl-2-((4-bromobenzyl)oxy)-2-cyclopropyl-3-((4-
methoxyphenyl)amino)-3-phenylpropanoate(4c) (2R,3S)-syn-
4c. 99% ee 1H NMR (400 MHz, CDCl3)
7.53 (s, 1H), 7.39 (d,
d
J¼7.8 Hz, 1H), 7.34 (dd, J¼7.8, 1.2 Hz, 2H), 7.32e7.26 (m, 3H),
7.24e7.13 (m, 5H), 7.08 (m, 2H), 6.65 (d, J¼9.0 Hz, 2H), 6.53 (d,
J¼8.9 Hz, 2H), 4.90e4.73 (m, 5H), 4.57 (m, 1H), 3.65 (m, 3H), 1.45
(m, 1H), 1.03 (m, 1H), 0.72 (m, 1H), 0.59e0.49 (m, 1H), 0.45 (m, 1H);
13C NMR (100 MHz, CDCl3)
d 170.00, 152.04, 141.56, 141.01, 139.15,
134.85, 130.57, 130.32, 129.72, 128.93, 128.54, 128.52, 128.39, 127.77,
127.52, 125.82, 122.38, 115.10, 114.77, 86.84, 66.76, 66.75, 64.62,
55.67, 15.05, 4.93, 1.58; HRMS (ESI) calcd for
C33H33BrNO4
DCM, DCE, CHCl3 was distilled over calcium hydride, and tolu-
ene were distilled over sodium. Cyclopropane diazo compounds 1
were prepared according to literature.8 Aldimines 3 was prepared
from condensation of the corresponding aldehydes with amines
according to the literature method.16 Chiral PPA 10ae10f were
[MþH]þ¼586.1593 found 586.1592; HPLC (Chiral ODeH,
l¼254 nm, hexane/alcohol¼100:1, flow rate¼1.0 mL/min),
tmajor¼10.74 min, tminor¼8.98 min.
prepared according to the literature procedure.17 4 A molecular
ꢀ
4.2.4. Benzyl-2-cyclopropyl-2-((3-methoxybenzyl)oxy)-3-((4-
sieve was dried in a Muffle furnace at 250 ꢁC over 5 h. Solvents for
the column chromatography were distilled before use. All reactions
were carried out under an argon atmosphere in well-dried
glasswares.
methoxyphenyl)amino)-3-phenylpropanoate(4d)
(2R,3S)-syn-
4d. 94% ee 1H NMR (400 MHz, CDCl3)
d
7.36 (m, 2H), 7.30e7.13 (m,
7H), 7.06 (m, 2H), 6.94 (m, 2H), 6.82 (m, 1H), 6.64 (d, J¼8.9 Hz, 2H),
6.52 (d, J¼8.9 Hz, 2H), 4.83 (m, 5H), 4.64 (m, 1H), 3.70 (s, 3H), 3.64
(s, 3H), 1.50 (m, 1H), 1.04 (m, 1H), 0.74 (m, 1H), 0.60e0.38 (m, 2H);
13C NMR (100 MHz, CDCl3)
d 170.11, 159.57, 151.82, 140.97, 140.85,
4.2. General procedure for chiral cyclopropane diazo com-
pound three-component reactions
139.29, 134.93, 129.14, 128.98, 128.45, 128.28, 127.66, 127.37, 119.46,
116.35, 114.95, 114.64, 113.39, 112.34, 86.70, 67.33, 66.58, 64.47,
55.65, 55.59, 55.07, 29.68, 15.11, 5.05, 1.57; HRMS (ESI) calcd for
A mixture of benzyl alcohol (0.2 mmol), imine (0.2 mmol),
Rh2(OAc)4 (1 mmol%), chiral phosphoric acid (R)-10a (5 mol %), and
C
34H35NNaO5 [MþNa]þ¼560.2413 found 560.2406; HPLC (Chiral

M. Li et al. / Tetrahedron 72 (2016) 2929e2934
2933
ODeH,
l
¼254 nm, hexane/alcohol¼200:1, flow rate¼1.0 mL/min),
128.55, 128.46, 127.70, 127.62, 122.82, 115.15, 114.80, 86.51, 77.36,
77.04, 76.72, 67.74, 66.85, 64.16, 55.63, 14.96, 5.26, 1.59; HRMS
tmajor¼28.67 min, tminor¼21.67 min.
(ESI) calcd for
C
33H32N2NaO6 [MþNa]þ¼575.2158 found
4.2.5. Benzyl-2-cyclopropyl-2-((2-methoxybenzyl)oxy)-3-((4-
575.2151; HPLC (Chiral ODeH,
hol¼200:1, flow rate¼1.0 mL/min), tmajor¼69.75 min,
tminor¼36.11 min.
l
¼254 nm, hexane/alco-
methoxyphenyl)amino)-3-phenylpropanoate(4e)
(2R,3S)-syn-
4e. 97% ee 1H NMR (400 MHz, CDCl3)
d
7.48e7.25 (m, 8H), 7.13 (m,
4H), 6.99e6.85 (m, 2H), 6.64 (dd, J¼8.8, 3.9 Hz, 2H), 6.50 (d,
J¼8.8 Hz, 2H), 5.12 (m, 1H), 4.81 (m, 4H), 3.84 (s, 3H), 3.74 (s, 1H),
3.66 (s, 3H),1.53 (m, 1H), 0.99 (m, 1H), 0.78e0.70 (m,1H), 0.61e0.41
4.2.10. Benzyl-2-(benzyloxy)-2-cyclopropyl-3-((4-methoxyphenyl)
amino)-3-(2-nitrophenyl)propanoate(4j) (2R,3S)-syn-4j. 97% ee 1H
(m, 2H); 13C NMR (100 MHz, CDCl3)
d
170.34, 156.79, 151.80, 141.32,
NMR (400 MHz, CDCl3)
d
7.68 (dd, J¼8.0, 1.4 Hz, 1H), 7.62 (dd, J¼8.0,
139.49, 135.19, 129.08, 128.85, 128.44, 128.35, 128.21, 128.18, 127.75,
127.65, 127.31, 120.49, 114.85, 114.79, 110.04, 86.67, 77.36, 77.04,
76.72, 66.48, 64.67, 62.43, 55.73, 55.34, 15.03, 5.06,1.62; HRMS (ESI)
calcd for C34H35NNaO5 [MþNa]þ¼560.2413 found 560.2414; HPLC
1.3 Hz,1H), 7.36e7.25 (m, 3H), 7.25e7.14 (m, 7H), 7.09e7.01 (m, 2H),
6.70e6.57 (m, 4H), 5.94 (s, 1H), 4.89 (d, J¼12.0 Hz, 1H), 4.75 (s, 2H),
4.69 (d, J¼12.0 Hz, 1H), 3.59 (m, 3H), 1.26e1.20 (m, 1H), 0.86e0.79
(m, 1H), 0.62e0.52 (m, 1H), 0.43e0.34 (m, 1H), 0.33e0.24 (m, 1H);
(Chiral IC,
l
¼254 nm, hexane/alcohol¼200:1, flow rate¼0.6 mL/
13C NMR (100 MHz, CDCl3)
d 169.68, 152.40, 150.45, 140.38, 138.79,
min), tmajor¼25.64 min, tminor¼19.55 min.
134.85, 134.20, 131.99, 130.58, 128.74, 128.46, 128.40, 128.31, 128.16,
127.67, 127.56, 124.34, 115.30, 114.83, 86.25, 77.36, 77.04, 76.72,
67.80, 66.92, 57.35, 55.64, 15.22, 5.12, 1.71; HRMS (ESI) calcd for
4.2.6. Benzyl-2-(anthracen-9-ylmethoxy)-2-cyclopropyl-3-((4-
methoxyphenyl)amino)-3-phenylpropanoate(4f) (2R,3S)-syn-4f. 98%
C
33H32N2NaO6 [MþNa]þ¼575.2158 found 575.2137; HPLC (Chiral
ee 1H NMR (400 MHz, CDCl3)
d
8.51 (s, 1H), 8.41 (d, J¼8.4 Hz, 2H),
ODeH,
l
¼254 nm, hexane/alcohol¼200:1, flow rate¼1.0 mL/min),
8.05 (d, J¼8.4 Hz, 2H), 7.52e7.43 (m, 2H), 7.42e7.31 (m, 5H),
7.19e7.08 (m, 5H), 7.04 (m, 2H), 6.58 (d, J¼8.9 Hz, 2H), 6.38 (d,
J¼8.9 Hz, 2H), 6.03 (d, J¼10.2 Hz, 1H), 5.79 (d, J¼10.2 Hz, 1H), 5.00
(m, 1H), 3.62 (s, 3H), 1.87e1.71 (m, 1H), 1.16 (m, 1H), 1.04 (m, 1H),
tmajor¼37.87 min, tminor¼85.64 min; (2S,3S)-anti-4j: 92% ee 1H NMR
(400 MHz, CDCl3)
d
7.81 (dd, J¼8.0, 1.1 Hz, 1H), 7.68e7.61 (m, 1H),
7.48e7.33 (m, 3H), 7.32e7.26 (m, 7H), 7.24e7.17 (m, 2H), 6.66 (s,
4H), 6.11 (d, J¼9.5 Hz,1H), 5.19e5.05 (m, 2H), 4.97 (d, J¼11.1 Hz,1H),
4.86 (d, J¼10.0 Hz, 1H), 4.71 (d, J¼11.1 Hz, 1H), 3.67 (s, 3H),
1.03e0.94 (m,1H), 0.65e0.55 (m,1H), 0.47e0.36 (m,1H), 0.35e0.20
0.75e0.59 (m, 2H); 13C NMR (100 MHz, CDCl3)
d 170.46, 151.83,
141.03, 139.36, 134.97, 131.57, 131.18, 129.66, 129.06, 128.87, 128.68,
128.52, 128.20, 127.64, 127.31, 126.01, 125.02, 124.91, 114.99, 114.65,
87.18, 77.36, 66.95, 64.70, 59.44, 55.67, 15.38, 5.59, 1.91; HRMS (ESI)
calcd for C41H38NO4 [MþH]þ¼608.2801 found 608.2780; HPLC
(m, 2H); 13C NMR (100 MHz, CDCl3)
d 168.38, 150.42, 149.42, 137.92,
137.05, 133.33, 131.52, 130.21, 129.49, 126.67, 126.43, 126.41, 126.36,
126.08, 125.64, 122.37, 114.57, 113.21, 112.84, 84.59, 65.44, 65.20,
55.24, 53.77, 11.43, 3.33, 0.00; HRMS (ESI) calcd for C33H32N2NaO6
[MþNa]þ¼575.2158 found 575.2186; HPLC (Chiral ODeH,
(Chiral ODeH,
min), tmajor¼32.06 min, tminor¼19.31 min.
l¼254 nm, hexane/alcohol¼50:1, flow rate¼1.0 mL/
l
¼254 nm, hexane/alcohol¼50:1, flow rate¼1.0 mL/min),
4.2.7. Benzyl-2-(benzyloxy)-3-(4-chlorophenyl)-2-cyclopropyl-3-
tmajor¼12.80 min, tminor¼11. 26 min.
((4-methoxyphenyl)amino)propanoate(4g) (2R,3S)-syn-4g. 90% ee
1H NMR (400 MHz, CDCl3)
d
7.44e7.19 (m, 11H), 7.10 (d, J¼7.9 Hz,
4.2.11. Benzyl-2-(benzyloxy)-3-((4-bromophenyl)amino)-2-
4H), 6.65 (d, J¼8.6 Hz, 2H), 6.48 (d, J¼8.6 Hz, 2H), 4.96e4.78 (m,
4H), 4.75 (s, 1H), 4.49 (s, 1H), 3.66 (s, 3H), 1.50 (m, 1H), 1.00 (m, 1H),
0.81e0.68 (m, 1H), 0.60e0.36 (m, 2H); 13C NMR (100 MHz, CDCl3)
cyclopropyl-3-phenylpropanoate (4k) (2R,3S)-syn-4k. 25% ee 1H
NMR (400 MHz, CDCl3)
(m, 4H), 6.43 (d, J¼8.8 Hz, 2H), 5.06e4.71 (m, 6H), 1.43 (m, 1H), 0.76
(m, 1H), 0.59e0.38 (m, 2H); 13C NMR (100 MHz, CDCl3)
169.85,
d 7.43e7.24 (m,10H), 7.20 (m, 3H), 7.15e7.01
d
170.07, 152.16, 140.73, 139.10, 137.96, 134.85, 133.16, 130.40,
d
128.64, 128.57, 128.48, 128.32, 127.87, 127.60, 127.47, 115.14, 114.80,
86.67, 67.62, 66.76, 64.07, 55.68, 15.08, 5.09, 1.56; HRMS (ESI) calcd
for C33H32ClNNaO4 [MþNa]þ¼564.1918 found 564.1940; HPLC
145.86, 139.01, 138.59, 134.80, 131.76, 128.93, 128.59, 128.52, 128.41,
128.27, 128.17, 127.80, 127.67, 127.53, 127.43, 115.17, 108.84, 86.54,
67.57, 66.79, 63.50, 15.13, 5.11, 1.61; HRMS (ESI) calcd for
(Chiral ODeH,
l
¼254 nm, hexane/alcohol¼200:1, flow
C
32H30BrNNaO3 [MþNa]þ¼578.1307 found 578.1311; HPLC (Chiral
rate¼1.0 mL/min), tmajor¼33.33 min, tminor¼17.36 min.
ODeH,
l
¼254 nm, hexane/alcohol¼200:1, flow rate¼1.0 mL/min),
tmajor¼47.93 min, tminor¼34.80 min.
4.2.8. Benzyl-2-(benzyloxy)-2-cyclopropyl-3-((4-methoxyphenyl)
amino)-3-(p-tolyl)propanoate(4h) (2R,3S)-syn-4h. 96% ee 1H NMR
4.2.12. Ethyl 2-(benzyloxy)-2-(bicyclo[4.1.0]heptan-7-yl)-3-(4-
(400 MHz, CDCl3)
d
7.44e7.28 (m, 8H), 7.22 (d, J¼7.7 Hz, 2H), 7.10
methoxyphenyl)-3-((4-methoxyphenyl)amino)propanoate
(2R,3S)-syn-4l. 92% ee IR (KBr) (cmꢀ1): 2927, 2854,1726,1513,1452,
1246,1178, 1118,1036; 1H NMR (400 MHz, CDCl3)
(4l)
(m, 2H), 6.98 (d, J¼7.7 Hz, 2H), 6.64 (d, J¼8.6 Hz, 2H), 6.50 (d,
J¼8.6 Hz, 2H), 4.94e4.67 (m, 5H), 4.54 (m, 1H), 3.66 (s, 3H), 2.26 (s,
d
7.46 (d, J¼7.1 Hz,
3H), 1.46 (m, 1H), 1.00 (m, 1H), 0.73 (m, 1H), 0.58e0.38 (m, 2H); 13
C
2H), 7.39 (t, J¼7.4 Hz, 2H), 7.35e7.26 (m, 3H), 6.77e6.70 (m, 2H),
6.69e6.62 (m, 2H), 6.58e6.48 (m, 2H), 4.90 (d, J¼11.3 Hz, 1H), 4.74
(d, J¼11.3 Hz, 1H), 4.69 (s, 1H), 4.53 (brs, 1H), 3.95e3.83 (m, 2H),
3.72 (s, 3H), 3.67 (s, 3H), 1.94e1.77 (m, 2H), 1.70e1.62 (m, 1H),
1.57e1.51 (m, 1H), 1.49e1.42 (m, 1H), 1.32e1.18 (m, 3H), 1.16e1.10
(m, 2H), 1.05 (t, J¼7.1 Hz, 3H), 0.98e0.91 (m, 1H); 13C NMR
NMR (100 MHz, CDCl3)
d 170.31, 151.92, 141.23, 139.37, 136.85,
136.29, 135.11, 128.88, 128.58, 128.47, 128.31, 128.25, 127.55, 127.32,
115.05, 114.77, 86.82, 67.52, 66.65, 64.34, 55.73, 21.15, 15.24, 5.02,
1.61; HRMS (ESI) calcd for C34H36NO4 [MþH]þ¼522.2644 found
522.2648; HPLC (Chiral ODeH,
l
¼254 nm, hexane/alcohol¼200:1,
flow rate¼1.0 mL/min), tmajor¼22.00 min, tminor¼17.04 min.
(100 MHz, CDCl3) d 170.76, 158.72, 151.92, 141.56, 139.56, 131.95,
130.02, 128.28, 127.51, 127.31, 115.25, 114.76, 113.00, 87.28, 67.63,
64.05, 60.52, 55.71, 55.10, 27.61, 22.97, 22.84, 21.12, 21.08, 16.62,
14.00, 13.42; HRMS (ESI) calcd for C33H40NO5 [MþH]þ¼530.2906
4.2.9. Benzyl-2-(benzyloxy)-2-cyclopropyl-3-((4-methoxyphenyl)
amino)-3-(4-nitrophenyl)propanoate(4i) (2R,3S)-syn-4i. 55% ee 1H
NMR (400 MHz, CDCl3)
d
7.98e7.86 (m, 2H), 7.47e7.41 (m, 2H),
found 530.2926; HPLC (Chiral ODeH,
l
¼254 nm, hexane/alco-
7.39e7.27 (m, 7H), 7.25 (m, 1H), 7.12e7.05 (m, 2H), 6.68e6.61 (m,
2H), 6.52e6.44 (m, 2H), 4.98e4.81 (m, 5H), 4.55 (m, 1H), 3.66 (s,
3H), 1.54e1.50 (m, 1H), 1.01 (m, 1H), 0.84e0.78 (m, 1H), 0.59 (m,
hol¼100:1,
flow
rate¼1.0
mL/min), min,
tmajor¼8.23
tminor¼6.70 min.
1H), 0.46 (m, 1H); 13C NMR (100 MHz, CDCl3)
d
169.75, 152.38,
4.2.13. Benzyl-cyclobut-1-enecarboxylate(5a). 1H NMR (400 Hz,
CDCl3)
7.20e7.40 (m, 5H), 6.81 (d, J¼0.8 Hz, 1H), 5.17 (s, 2H), 2.74
147.13, 147.10, 140.11, 138.81, 134.55, 129.86, 128.84, 128.70,
d

2934
M. Li et al. / Tetrahedron 72 (2016) 2929e2934
(m, 2H), 2.46 (m, 2H). This 1H NMR data were consisted with the
literature.8
References and notes
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51281 A1, 2015; (d) Sesha, R. U.S. Patent: 172,525 A1, 2007; (e) Gruenenthal G.
U.S. Patent: 242,617 A1, 2004; (f) Singh, N. N.; Singh, N. N. U.S. Patent: 42,281
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4.3. General procedure for the base-promoted cyclization of
syn-4j
2. Faust, R. Angew. Chem., Int. Ed. 2001, 40, 2251 Haslam, E. Shikimic Acid Metab-
olism and Metabolites, John Wiley & Sons: New York, 1993.
A solution of LHMDS (5 mmol) in dry THF was slowly added over
a cooled (ꢀ20 ꢁC) solution of syn-4j (1 mmol) in dry THF(15 mL).
The mixture was stirred for 5 min at this temperature and
quenched with a 1 M HCl solution (30 mL). The mixture was
extracted with CH2Cl2 (3ꢂ30 mL), the collected organic fractions
were dried over Na2SO4 and filtered, and the filtrate was concen-
trated to give a residue which was subjected to HPLC for the ee
values. The crude product was further purified by column chro-
matography on silica gel (EtOAc/light petroleum ether¼1:50e1:10)
to get the final product syn-6.
3. (a) Pesyan, N. N.; Rezaee, M. Monatsh Chem. 2014, 145, 1165; (b) Voituriez, A.;
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4.3.1. (3R,4S)-3-(Benzyloxy)-3-cyclopropyl-1-(4-methoxyphenyl)-4-
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(2-nitrophenyl)azetidin-2-one(6) (3R,4S)-syn-6. 92% ee 1H NMR
(400 MHz, CDCl3)
d
8.21 (d, J¼8.0 Hz, 1H), 7.60e7.44 (m, 4H),
7.40e7.34 (m, 2H), 7.33e7.23 (m, 4H), 6.85 (d, J¼8.8 Hz, 2H), 5.95 (s,
1H), 4.87 (dd, J¼33.9, 10.6 Hz, 2H), 3.78 (s, 3H), 0.89e0.78 (m, 1H),
0.78e0.66 (m,1H), 0.61e0.50 (m, 1H), 0.36e0.25 (m, 1H), 0.21e0.09
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(m, 1H); 13C NMR (100 MHz, CDCl3)
d 162.77, 154.20, 145.60, 135.08,
130.93, 129.12, 127.70, 127.14, 126.32, 125.93, 125.57, 125.31, 123.06,
116.56, 112.13, 92.46, 65.48, 59.71, 53.07, 9.44, ꢀ0.00, ꢀ1.40; HRMS
(ESI) calcd for C26H24N2NaO5 [MþNa]þ¼467.1583 found 467.1605;
HPLC (Chiral ODeH,
rate¼1.0 mL/min), tmajor¼37.64 min, tminor¼24.65 min.
l
¼254 nm, hexane/alcohol¼50:1, flow
Acknowledgements
We greatly thank NSFC (21125209, and 21332003), STCSM
(15ZR1411000) and Stake Key Laboratory of Advanced Technology
for Materials Synthesis and Processing (2015-KF-11) for financial
support.
13. Guo, Z.; Huang, H.; Fu, Q.; Hu, W. H. Synlett 2006, 2486.
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Zhang, Z. Y. J. Am. Chem. Soc. 2011, 133, 8428; (b) Johnston, J. N.; Muchalski, H.;
Troyer, T. L. Angew. Chem., Int. Ed. 2010, 49, 2290; (c) Akiyama, T.; Itoh, J.; Yokota,
K.; Fuchibe, K. Angew. Chem., Int. Ed. 2004, 43, 1566.
ꢁ
15. Vicario, J. L.; Badıa, D.; Carrillo, L. J. Org. Chem. 2001, 66, 9030.
Supplementary data
16. Shiino, M.; Watanable, Y.; Umezawa, K. Bioorg. Med. Chem. 2001, 9, 1233.
17. For preparation of 10ae10f: (a) Hu, W. H.; Zhou, J.; Xu, X. F.; Liu, W. J.; Gong, L. Z.
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Davis, W. M.; Hoveyda, A. H.; Schrock, R. R. J. Am. Chem. Soc. 1999, 121, 8251; (c)
Klussmann, M.; Ratjen, L.; Hoffmann, S.; Wakchaure, V.; Goddard, R.; List, B.
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Am. Chem. Soc. 2006, 128, 84.
Supplementary data include general synthesis information,
synthetic scheme and procedure for sulfonamides, characterization
data and 1H, 13C NMR, IR, HRMS spectra of all the products.
Supplementary data associated with this article can be found in
the online version, at http://dx.doi.org/10.1016/j.tet.2016.04.006.