Diastereoselective cyclopropanation of electron-deficient alkenes via metal glycal carbenes

Article abstract of DOI:10.1055/s-2008-1067151

Silyl- and isopropylidene-O-protected chromium glucal and galactal carbenes have been synthesized from their glycal precursors according to the Fischer route. NMR studies indicate a preferred ⁵H₄ or ⁴H₅ conformation, depending on the nature of the protective group and the configuration at C-4. The complexes with glycal carbenes have been applied to the diastereoselective cyclopropanation of methyl crotonate and γ-crotonolactone. Georg Thieme Verlag Stuttgart.

Full text of DOI:10.1055/s-2008-1067151

PAPER
2183
Diastereoselective Cyclopropanation of Electron-Deficient Alkenes via Metal
Glycal Carbenes
D
iastereoselec
r
tive
C
yc
a
lopropanati
n
on of
E
lectro
k
n-Deficient
Alken
O
es tto, Karl Heinz Dötz*
Kekulé-Institut für Organische Chemie und Biochemie, Rheinische Friedrich-Wilhelms Universität Bonn,
Gerhard-Domagk-Str. 1, 53121 Bonn, Germany
Fax +49(228)735813; E-mail: doetz@uni-bonn.de
Received 18 April 2008
Dedicated to Professor R. W. Hoffmann on the occasion of his 75th birthday
Spirocyclopropanes serve as a rigid scaffold in saccharide
Abstract: Silyl- and isopropylidene-O-protected chromium glucal
and galactal carbenes have been synthesized from their glycal pre-
cursors according to the Fischer route. NMR studies indicate a pre-
synthesis; sugar diazirine18 and lactone hydrazone
derivatives19 as well as metal glycosylidenes20 have been
used as glycosylidene transfer reagents. Metal-mediated
5
4
ferred H4 or H5 conformation, depending on the nature of the
protective group and the configuration at C-4. The complexes with cyclopropanations mainly rely on zinc carbenoids
(Simmons–Smith reaction)21 and rhodium carbenes.22
Herein we report on a complementary diastereoselective
glycal carbenes have been applied to the diastereoselective cyclo-
propanation of methyl crotonate and g-crotonolactone.
Key words: carbene complexes, carbohydrates, cycloadditions,
diastereoselective synthesis, organometallic reagents
cyclopropanation of electron-deficient alkenes based on
chromium glycal carbenes.
The synthesis of the chromium glycal carbenes starts from
properly protected glycals 1–3 (Figure 1), which are ac-
cessible by established silylation (2,6-lutidine/silyl
triflate23 or imidazole/silyl chloride24) or isopropylidena-
tion protocols.15 Metalation at C-1 followed by addition to
hexacarbonylchromium and final O-alkylation affords the
chromium glycal carbenes.
The chiral information readily accessible in customary
carbohydrates provides an attractive approach to the
chiral modification of organometallics that may be ap-
plied to stereoselective organic synthesis focusing on ei-
ther stereocontrolled metal-mediated C–C bond formation
or on specific modification of carbohydrates based on or-
ganometallic protocols. Examples of a successful combi-
nation of carbohydrate and organometallic chemistry are
still rare. Glycosyl complexes of manganese1 and iron2
have been prepared and used as C-nucleophiles; chromi-
um and tungsten alkenyl carbenes have been labeled with
carbohydrates.3 Transition metals applied to C-glycoside
synthesis have been restricted mainly to manganese,4
samarium,5 and palladium.6 The application of diacetyl
glucose (‘DAGO’) as a chiral auxiliary marked a break-
through in enantioselective allylation and aldol reactions
based on titanium C-nucleophiles.7 More generally, sugar-
based phosphines have evolved as efficient ligands in ca-
talysis of, e.g., hydrogenation8 or palladium-catalyzed
aqueous-phase cross-coupling reactions.9 Recently, car-
bohydrates have been applied as organocatalysts in
substoichiometric10 or catalytic11 amounts.
OTIPS
OTIPS
O
TBDMSO
TBDMSO
TIPSO
O
O
TIPSO
O
O
1
2
3
OTIPS
Figure 1 Silyl- and isopropylidene-O-protected glucals 1 and 2 and
galactal 3
In contrast to D-glucal 1, which can be obtained in a one-
step persilylation, the synthesis of D-galactal 3 requires a
stepwise one-pot protocol. For this, the more reactive pri-
mary hydroxy group is first protected by triisopropylsilyl
(which is too bulky for a single-step persilylation) fol-
lowed by subsequent complete silylation with imidazole/
tert-butyldimethylsilyl chloride. tert-Butyldimethylsilyl
Our interest in chiral Fischer-type metal carbenes12 has protection at C-6 turned out to be sensitive towards tert-
led us to glycosylcarbene and glycosylidene complexes,13 butyllithium, which is required as a base in the following
which have been applied to diastereoselective stannylation.25
cycloaddition14 and annulation reactions15 as well as to the
conversion of customary carbohydrates into non-natural
azasugars.16 Metal glycosyl carbenes bearing unprotected
Two complementary routes to the mixed-protected glucal
2 have been investigated. Compared to sequential 4,6-O-
isopropenylidenation and silylation starting from depro-
hydroxy groups represent amphiphiles, which may be
tected glucal, an alternative procedure starting with com-
plete deprotection of peracetylglucopyranose and
used for the generation of organometallic gels.17
involving a 1-O-(phenylsulfanyl)-monoprotected glucose
intermediate turned out to afford higher overall yields of
SYNTHESIS 2008, No. 14, pp 2183–2190
x
x.
x
x
.
2
0
0
8
2.
Advanced online publication: 18.06.2008
DOI: 10.1055/s-2008-1067151; Art ID: C01208SS
© Georg Thieme Verlag Stuttgart · New York
Clean C-1 lithiation of the glycal precursors is best
achieved by a transmetalation protocol based on a tert-

2184
F. Otto, K. H. Dötz
PAPER
Table 1 Diagnostic 1H NMR Spectroscopic Coupling Constants for
the Glycal Skeleton in Chromium Glycal Carbenes 7–9a
butyllithium – tri-n-butyltin chloride – n-butyllithium se-
quence.25 It affords stannyl glycals 4–6 in 76–89% yield
(Scheme 1) which can be stored for months and allow a
mild and high-yield relithiation. Addition of the resulting
lithioglycal intermediates to hexacarbonylchromium gen-
erates acylchromates, which undergo O-alkylation with
trimethyloxonium tetrafluoroborate to give the chromium
glycal carbenes 7–9 in 61–70% yield (Scheme 1).
3
Carbene JH-2,H-3
(Hz)
4JH-2,H-4
(Hz)
3JH-3,H-4
(Hz)
4JH-3,H-5
(Hz)
3JH-4,H-5
(Hz)
7
8
9
5.47
2.61
2.21
1.49
–
1.99
7.83
3.37
ca. 1.9
ca. 1.7
ca. 10
ca. 2
–
–
ca. 2.2
OR3
OR3
a 1H NMR: 7: CDCl3, 500 MHz; 8: CDCl3, 400 MHz; 9: toluene-d8,
500 MHz, 243 K.
R2O
R2O
OMe
O
O
R1O
R1O
Cr(CO)5
1–3
7–9
a
OR3
b
HO
R2O
C-4
C-5
HO
O
Sn(n-Bu)3
R1O
4–6
1, 4, 7: glucal: R1 = R2 = R3 = TIPS
2, 5, 8: glucal: R1 = TIPS, R2/R3 = O-isopropylidene
3, 6, 9: galactal: R1 = R2 = TBDMS, R3= TIPS
H
C-4
C-5
4H5-conformer
H
5H4-conformer
(glucal: OR2 equatorial; galactal: OR2 axial in the 4H5-
conformation as shown in this scheme)
Figure 2 The vinylogous anomeric effect in glucal conformers
Scheme 1 Synthesis of glycal carbene complexes 7–9 via stannanes
4–6 from protected glycals 1–3. Reagents and conditions: (a) t-BuLi
(4.5 equiv), THF, –78 °C to 0 °C, 28 min (4, 5), 25 min (6), then n-
Bu3SnCl (3.0 equiv), THF, –78 °C, 22 min; 78% (4), 89% (5), 76%
(6); (b) n-BuLi (1.1 equiv), THF, –78 °C, 45 min (7), 30 min (8),
90 min (9), then Cr(CO)6 (1.2 equiv), –37 °C, 90 min (7), –37 °C,
60 min (8), –40 °C, 60 min (9); then [Me3O]+[BF4]– (1.2 equiv),
CH2Cl2, r.t., 90–120 min; 70% (7), 61% (8), 70% (9).
The NMR spectrum of chromium galactal carbene 9 re-
corded at room temperature does not indicate the prefer-
ence of a single conformer. However, the H-2/H-3
coupling observed at 243 K (3JH-2,H-3 = 2.21 Hz) resem-
bles that observed for the bicyclic chromium glucal car-
bene 8 at ambient temperature (3JH-2,H-3 = 2.61 Hz), and
this suggests that both complexes adopt a 4H5 conforma-
tion (Figure 3) under these conditions; this correlation is
further supported by comparable long-range coupling
constants 4JH-2,H-4 observed for the 5H4 conformation of 7
(1.49 Hz) and – due to the inversion of configuration at C-
4 – expected for a 4H5 conformation of 9 (ca. 2.2 Hz).
The conformation of the chromium glycal carbenes was
analyzed on the basis of their 1H NMR spectra. In partic-
3
3
ular, the coupling constants JH-2,H-3 and JH-4,H-5 along
with the long-range coupling constants H-2/H-4 and H-3/
H-5 are indicative for a preference of either a 4H5 or a 5H4
half-chair conformation.26 A rather large H-2/H-3 cou-
pling (3JH-2,H-3 = 5.47 Hz) combined with distinctly small-
er H-4/H-5, H-3/H-4, H-2/H-4, and H-3/H-5 couplings
(ca. 1.5–1.7 Hz), as observed for the per(triisopropylsi-
lyl)-protected glucal carbene complex 7, suggests a pref-
A comparison of glucal and galactal carbene complexes 7
and 9 reveals that the preferred conformation is controlled
by the configuration of the glycal and suggests that the
sterically favored all-cis pattern equatorial–axial–equato-
rial at the positions C-3, C-4, and C-5 as disclosed in 9
overrules the vinylogous anomeric effect stabilizing the
all-axial 3,4-trans-3,5-cis pattern preferred in 7, and thus
indicates a delicate balance of steric and electronic ef-
fects. The preferred conformations of chromium glycal
carbenes 7–9 are depicted in Figure 3.
5
erence for the H4 conformation on the NMR timescale
(Table 1, Figure 2). The conformation is controlled by the
choice of the protective groups. The isopropylidene pro-
tection of the 4,6-OH groups in glucal carbene complex 8
forces the glucal ring into a 4H5 conformation, as support-
ed by large H-4/H-5 (3JH-4,H-5 ≈ 10 Hz) and small H-2/H-3
(3JH-2,H-3 = 2.61 Hz) coupling, combined with the absence
of detectable 4J coupling constants for H-2/H-4 and H-3/
H-5. The preferred 4H5 conformation reflects the rigidity
of the glucal ring imposed by the cyclic O-isopropylidene
ketal moiety. The different conformations observed for
chromium glucal carbenes 7 and 8 may be rationalized by
the vinylogous anomeric effect (Figure 2), which reveals
a better stereoelectronic compensation of the dipole mo-
ments involving the ring oxygen and the oxygen atom at
Fischer-type metal carbenes have been widely applied to
the cyclopropanation of alkenes.28 In order to attach a gly-
cal moiety to a rigid scaffold bearing an additional func-
tionality, we explored the scope of chromium glycal
carbenes 7–9 in the cyclopropanation of methyl crotonate
and g-crotonolactone. In particular, we were interested in
the influence of the chiral centers in the glycal skeleton on
the stereochemical outcome of the cycloaddition.
Preliminary experiments revealed that an efficient car-
bene transfer from the metal glycal carbene to both accep-
tor alkenes is limited to a small temperature window:
5
C-3 for the H4-conformer of 7. The preference of this
conformation over 4H5 is even enhanced if the oxygen at
C-3 is connected to a weak acceptor (silyl) substituent.27
Synthesis 2008, No. 14, 2183–2190 © Thieme Stuttgart · New York

PAPER
Diastereoselective Cyclopropanation of Electron-Deficient Alkenes
2185
6CH2OR
OR3
R2O
4
OR
5
RO
RO
1
OMe
O
2
O
3
O
3
2
R1O
1
CH2OR
4
5
6
Cr(CO)5
7–9
OR
5H4-conformation
4H5-conformation
COOMe
(10, 1.0 equiv) 82 °C, 90–180 min
n-heptane
OTIPS
TIPSO
O
O
TIPSO
OR3
OR3
OMe
O
OMe
O
R2O
R2O
R1O
diastereomeric pair I
OR3
MeO
MeO
COOMe
COOMe
7
Cr(CO)5
Cr(CO)5
8
O
O
R1O
4H5-conformation
5H4-conformation
OTIPS
a
b
OTIPS
TBDMSO
TBDMSO
OR3
R2O
R2O
R1O
diastereomeric pair II
OMe
MeO
MeO
O
COOMe
COOMe
O
O
R1O
Cr(CO)5
4H5-conformation
9
c
d
(stable below 244 K)
Figure 3 Preferred conformations of glucal and galactal carbene
complexes 7–9
Scheme 2 Cyclopropanation of methyl (E)-crotonate by chromium
glycal carbenes 7–9
Below 80 °C the cyclopropanation was very slow, and
above 90 °C the formation of side products resulting from
decomposition of the carbene complex prevailed. As ob-
served previously for the cyclopropanation of dienoates,29
n-heptane turned out to be the solvent of choice. The cy-
clopropanation of methyl (E)-crotonate (10) by glycal car-
bene complexes 7–9 afforded a complex mixture of
diastereomeric cyclopropyl glycals 11–13 in overall
yields of 59–75% (Scheme 2, Table 2). A stereochemical
analysis of the cyclopropanation products revealed that in
each series (A–C) two pairs of diastereomers a/b and c/d
were obtained, in which the E configuration of the alkene
was preserved in a trans relation between the methoxycar-
bonyl and methyl groups in the cyclopropane skeleton
(Scheme 2, Table 2). Independent of the nature of the gly-
cal and its protection pattern, a trans configuration of the
glycal and the methyl substituent is observed for the major
diastereomeric pair I, which prevails over the pair of dia-
stereomers II, bearing cis-related glycal and methyl
groups, by a factor of ca. 3–6 (Table 2).
Table 2 Yields and Diastereomeric Excesses of the Diastereomeric
Pairs I and II Obtained by Cyclopropanation of Methyl (E)-Crotonate
by Chromium Glycal Carbenes 7–9
Starting material Seriesa
Product pair
11a/11b
11c/11d
12a/12b
12c/12d
13a/13b
13c/13d
Yields (%) de (%)
7
7
8
8
9
9
A
A
B
B
C
C
31:13
9:7
41
13
45:18
7:5
43
17
47:<1
6:2
>96
50
a Series A, glucal 7 (R1 = R2 = R3 = TIPS); B, glucal 8 (R1 = TIPS;
R2,R3 = O-isopropylidene); C, galactal 9 (R1 = R2 = TBDMS; R3 =
TIPS); OR2 equatorial in glucal and axial in galactal in the 4H5 con-
formation shown in Scheme 2.
O
O
TIPSO
An extension of the cyclopropanation to the endocyclic
analogue g-crotonolactone (14) affords a [3.1.0]-bicyclic
scaffold, but lowers the yield dramatically to give only
(from the reaction between galactal 8 and 14) 5% of an in-
separable 2.4:1 mixture of diastereomers (41% de)
(Scheme 3). Generally, the cis coupling constants 3JH,H cis
for vicinal cyclopropyl hydrogen atoms exceed the trans
coupling constants 3JH,H trans.30 In cyclopropane derivative
OMe
O
Cr(CO)5
8
n-heptane,
O
82 °C,
160 min,
5%
O
(14, 4.0 equiv)
15a,b, however, the vicinal coupling constant (3JH,H cis
=
O
O
TIPSO
OMe
6.97 Hz) is in the same range as the coupling constants ob-
served for the trans-disubstituted cyclopropanes 11–13
(3JH,H trans = 6.75–7.16 Hz); this reflects the geometry of
the bicyclic [3.1.0] skeleton.31
O
O
O
15a,b
Scheme 3 Cyclopropanation of g-crotonolactone with glucal car-
bene complex 8
In conclusion, silyl- and isopropylidene-substituted glucal
and galactal moieties have been incorporated into Fischer-
Synthesis 2008, No. 14, 2183–2190 © Thieme Stuttgart · New York

2186
F. Otto, K. H. Dötz
PAPER
13C NMR (125 MHz, benzene-d6, 342 K): d = 143.5 (1 C, C-1),
102.8 (1 C, C-2), 80.4 (1 C, C-3), 69.5, 66.2 (2 C, C-4, C-5), 62.0 (1
C, C-6), 26.3 [6 C, TBDMS-C(CH3)3], 18.6, 18.5 [2 C, TBDMS-
C(CH3)3], 18.3, 18.2 [6 C, TIPS-CH(CH3)2], 12.7 [3 C, TIPS-
CH(CH3)2], –3.9, –4.3, –4.5, –4.7 (4 C, TBDMS-SiCH3).
3
type chromium carbenes. The conformation of the glucal
carbene complexes is controlled by the pattern of the pro-
tective groups, whereas the per(triisopropylsilyl)-protect-
ed galactal carbene complex is conformationally flexible
at room temperature. The chromium glycal carbenes have
been applied to a moderately diastereoselective cyclopro-
panation of electron-deficient E- and Z-alkenes, attaching
a rigid cyclopropyl or [3.1.0]-bicyclic scaffold to the gly-
cal. The cyclopropyl glycals are attractive reagents for
cycloisomerization32 and rearrangement reactions – espe-
cially for cyclopentenes33 – to incorporate the sugar skel-
eton into a further elaborated framework.
1H NMR (500 MHz, toluene-d8, 373 K): d = 6.34 (d, JH-1,H-2
=
6.13 Hz, 1 H, H-1), 4.77 (dd, 3JH-2,H-1 = 6.13 Hz, 3JH-2,H-3 = 4.17 Hz,
1 H, H-2), 4.44 (dd, 2JH-6,H-6¢ = 10.66 Hz, 3JH-6,H-5 = 7.38 Hz, 1 H, H-
6), 4.37 (m, 3JH-3,H-2 = 4.17 Hz, 3JH-3,H-4 ≈ 3.5 Hz, 3JH-5,H-6 = 7.38 Hz,
3
3JH-5,H-4 ≈ 3.5 Hz, JH-5,H-6¢ = 3.15 Hz, 2 H, H-3, H-5), 4.33 (dd,
3
2JH-6¢H-6 = 10.66 Hz, JH-6¢H-5 = 3.15 Hz, 1 H, H-6¢), 1.35–1.31 (m,
21 H, TIPS-H), 1.16, 1.15 [s, 18 H, TBDMS-C(CH3)3], 0.32, 0.31,
0.29, 0.28 (s, 12 H, TBDMS-SiCH3).
13C NMR (125 MHz, toluene-d8, 373 K): d = 144.3 (1 C, C-1),
103.6 (1 C, C-2), 81.3 (1 C, C-3), 70.5, 67.1 (2 C, C-4, C-5), 62.9 (1
C, C-6), 27.0 [6 C, TBDMS-C(CH3)3], 19.1–18.9 [7 C, TBDMS-
C(CH3)3, TIPS-CH(CH3)2], 13.6 [3 C, TIPS-CH(CH3)2], –3.2, –3.6,
–3.7, –3.9 (4 C, TBDMS-SiCH3).
All reactions were carried out under an atmosphere of argon, and
Schlenk techniques were used. Solvents used for reactions and
chromatography were dried by distillation from CaH2 (CH2Cl2),
LAH (PE, n-heptane), and LAH/then K (DMF, THF) and saturated
with argon. Column chromatography was performed on degassed
silica gel (Machery Nagel, type 60, 0.063–0.2 mm). FT-IR spectra
were obtained on a Nicolet Magna 550 spectrometer, and NMR
spectra were obtained on a Bruker DRX or AMX 500 spectrometer.
An additional abbreviation used to designate NMR peaks is p (pseu-
do, e.g. in pt, pdt, pq). MS (EI) and HRMS–FAB were carried out
on Kratos MS-50 and Concept 1 H spectrometers, respectively. The
protected glycals 1–334 and glucal carbene complexes 7 and 815
were prepared as previously described. Silyl triflates23 and silyl
chlorides24 were used for glycal protection. The stannylation reac-
tions were carried out according to a literature procedure.25
MS (EI, 70 eV): m/z (%) = 529.4 (<1) [M+ – H], 515.4 (1.7), 487.4
(100), 473.3 (35.8), 431.3 (7.2), 343.2 (30.9), 301.2 (48.4), 245.1
(8.6), 157.1 (14.2), 115.0 (11.1).
HRMS–FAB: m/z calcd for C24H51O4Si3 [M+ – C3H7]: 487.309519;
found: 487.3096.
1,5-Anhydro-3,4-di-O-(tert-butyldimethylsilyl)-2-deoxy-6-O-
(triisopropylsilyl)-1-(tri-n-butylstannyl)-D-lyxo-hex-1-enitol (6)
A 1.5 M soln of t-BuLi in n-pentane (31.95 mL, 47.93 mmol,
4.5 equiv) was added dropwise at –78 °C to a soln of galactal 3
(6.55 g, 10.65 mmol) in THF (80 mL). The mixture was stirred for
25 min at 0 °C and cooled again to –78 °C before n-Bu3SnCl
(8.6 mL, 31.95 mmol) was added dropwise. After 20 min, the cool-
ing bath was removed and the reaction was quenched by the addi-
tion of ice (100 g). The resulting aqueous layer was extracted with
Et2O (3 × 100 mL) and the organic phase was washed with H2O (3
× 100 mL) and brine (100 mL) and dried (MgSO4). The solvent was
evaporated in vacuo and the residue was purified by chromatogra-
phy (silica gel, PE–CH2Cl2, 20:1 + 1% Et3N).
1,5-Anhydro-3,4-di-O-(tert-butyldimethylsilyl)-2-deoxy-6-O-
(triisopropylsilyl)-D-lyxo-hex-1-enitol (3)
TIPSCl (6.44 mL, 30.11 mmol) was added dropwise to a soln of D-
galactal (4.06 g, 27.37 mmol) and imidazole (3.73 g, 54.74 mmol)
in DMF (50 mL) at 0 °C. The mixture was stirred for 6 h at r.t., and
the persilylation was completed by the addition of imidazole
(8.39 g, 123.17 mmol) and TBDMSCl (12.38 g, 82.11 mmol) and
stirring of the mixture at 65 °C for 18 h. The reaction was quenched
by the addition of H2O (50 mL), and the aqueous layer was extract-
ed with Et2O (3 × 50 mL). The combined organic layers were
washed with H2O (3 × 50 mL) and brine (50 mL) and dried
(MgSO4). The product was purified by chromatography (silica gel,
PE–CH2Cl2, 3:1).
Yield: 6.61 g (76%); colorless oil.
1H NMR (500 MHz, toluene-d8, 223 K): d = 5.29/5.08 (d [dd]/s [d]
[3J119Sn,H-2a = 26.13 Hz]/[3J119Sn,H-2b = 29.11 Hz],
5.63 Hz, 2 H, H-2a/H-2b), 4.77, 4.65, 4.46, 4.37, 4.30–4.25, 4.05
3JH-2a,H-3a
=
(m, 10 H, H-3a, H-3b, H-4a, H-4b, H-5a, H-5b, H-6a, H-6b, H-6a¢,
3
H-6b¢), 1.92 (m, 12 H, H-8a, H-8b), 1.68 (tq, tq, JH-9a,H-8a ≈ 8 Hz,
Yield: 10.44 g (72%); colorless oil.
3JH-9b,H-8b ≈ 8 Hz, 3JH-9a,H-10a ≈ 7.5 Hz, 3JH-9b,H-10b ≈ 7.5 Hz, 12 H, H-
9a, H-9b), 1.55–1.10 [m, 60 H, TIPS-H, TBDMS-C(CH3)3, H-7a,
H-7b, H-10a, H-10b) 0.60–0.14 (s, 24 H, TBDMS-SiCH3].
1H NMR (500 MHz, benzene-d6): d = 6.25 (d, 3JH-1,H-2 = 5.83 Hz, 1
H, H-1), 4.62 (dd, 3JH-2,H-1 = 5.83 Hz, 3JH-2,H-3 = 4.67 Hz, 1 H, H-2),
3
4.50–3.90 (br, 5 H, H-3, H-4, H-5, H-6, H-6¢), 4.11 (pt, JHH
≈
13C NMR (125 MHz, toluene-d8, 223 K): d = 162.4/161.7 (2 C, C-
1a/C-1b), 114.9/114.2 (2 C, C-2a/C-2b), 81.3/78.9 (2 C, C-3a/C-
3b), 70.2, 68.7, 67.0, 64.7, (4 C, C-4a, C-4b, C-5a, C-5b), 63.6/61.6
(2 C, C-6a/C-6b), 30.0/30.0 (6 C, C-8a/C-8b), 28.6/28.6 ([d/d,
3
3.7 Hz, JHH ≈ 3.7 Hz, 1 H, H-4), 1.25–1.15 (m, 21 H, TIPS-H),
1.05–0.90 [s, 18 H, TBDMS-C(CH3)3], 0.15–0.09 (s, 12 H,
TBDMS-SiCH3).
13C NMR (125 MHz, benzene-d6): d = 143.4 (1 C, C-1), 102.8 (1 C,
C-2), 80.1 (br, 1 C, C-3), 69.1, 65.5 (br, 2 C, C-4, C-5), 61.6 (br, 1
C, C-6), 26.1 [6 C, TBDMS-C(CH3)3], 18.5 [2 C, TBDMS-
C(CH3)3], 18.3, [6 C, TIPS-CH(CH3)2], 12.4 [3 C, TIPS-
CH(CH)3)2], –4.1, –4.4, –4.6, –4.9 (4 C, TBDMS-SiCH3).
3
2J119Sn,C-9a = 56.86 Hz/2J119Sn,C-9b = 59.54 Hz],
6 C, C-9a/C-9b),
26.8, 26.8, 26.3, 26.3 [6 C, TBDMS-C(CH3)3], 19.4, 18.7 [4 C, TB-
DMS-C(CH3)3], 18.9, 18.9, 18.7 [12 C, TIPS-CH(CH3)2], 14.9/14.8
(9 C, C-10a/C-10b), 12.6, 12.3 [6 C, TIPS-CH(CH3)2], 10.1/10.0 (6
C, C-7a/C-7b), –2.8, –3.8, –4.3, –4.3, –4.4, –4.5, –5.0 (8 C,
TBDMS-SiCH3).
1H NMR (500 MHz, benzene-d6, 342 K): d = 6.23 (dd, JH-1,H-2
=
6.11 Hz, 4JH-1,H-3 = 0.89 Hz, 1 H, H-1), 4.64 (dd, 3JH-2,H-1 = 6.11 Hz,
1H NMR (500 MHz, toluene-d8, r.t.): d = 5.10 (br, 1 H, H-2), 4.60–
2
3JH-2,H-3 = 4.17 Hz, 1 H, H-2), 4.34 (dd, JH-6,H-6¢ = 10.83 Hz,
4.20 (br, 5 H, H-3, H-4, H-5, H-6, H-6¢), 1.89 (m [3J119Sn,H-8
≈
3JH-6,H-5 = 7.55 Hz, 1 H, H-6), 4.27 (m, 1 H, H-5), 4.21 (dd,
2JH-6¢H-6 = 10.83 Hz, 3JH-6¢H-5 = 3.13 Hz, 1 H, H-6¢), 4.20 (br m, 1 H,
39 Hz], 3JH-8,H-7 ≈ 8 Hz, 3JH-8,H-7¢ ≈ 8 Hz, 3JH-8,H-9 ≈ 7.5 Hz, 6 H, H-
8), 1.63 (tq, 3JH-9,H-8 ≈ 7.5 Hz, 3JH-9,H-10 ≈ 7.5 Hz, 6 H, H-9), 1.45–
3
3
2
1.32 (m, 21 H, TIPS H), 1.30 (dd, dd, JH-7,H-7¢ ≈ 8 Hz, JH-7,H-8
3
H-3), 4.15 (pt, JHH ≈ 3.7 Hz, JHH ≈ 3.7 Hz, 1 H, H-4), 1.23–1.15
(m, 21 H, TIPS-H), 1.02 [s, 18 H, TBDMS-C(CH3)3], 0.20–0.10 (s,
12 H, TBDMS-SiCH3).
≈
3
8 Hz, JH-7¢H-8 ≈ 8 Hz, 6 H, H-7, H-7¢), 1.25–1.12 [m, 18 H,
3
TBDMS-C(CH3)3], 1.19 (t, JH-10,H-9 ≈ 7.5 Hz, 9 H, H-10), 0.60–
0.20 (s, 12 H, TBDMS-SiCH3).
Synthesis 2008, No. 14, 2183–2190 © Thieme Stuttgart · New York

PAPER
Diastereoselective Cyclopropanation of Electron-Deficient Alkenes
2187
13C NMR (125 MHz, toluene-d8, r.t.): d = 162.9 (1 C, C-1), 114.7 (1
C, C-2), 80.8 (1 C, C-3), 63.2 (1 C, C-4, C-5, or C-6), 30.0 ([d,
2J119Sn,C-8 = 20.63 Hz] 3 C, C-8), 28.3 ([d, 3J119Sn,C-9 = 56.14 Hz], 3
C, C-9), 26.8 [6 C, TBDMS-C(CH3)3], 18.9 [6 C, TIPS-CH(CH3)2],
=
336.61 Hz, 3 C, C-7), –3.3, –3.8, –3.8, –4.2 (4 C, TBDMS-SiCH3).
TBDMS-C(CH3)3], 18.6, 18.5 [6 C, TIPS-CH(CH3)2], 12.5 [3 C,
TIPS-CH(CH)3)2], –3.0, –4.2, –4.3, –4.5 (4 C, TBDMS-SiCH3).
1H NMR (500 MHz, toluene-d8, r.t.): d = 5.70–4.40 (br, 6 H, H-2,
H-3, H-4, H-5, H-6, H-6¢), 4.28 (s, 3 H, OMe), 1.40–1.35 (21 H,
TIPS-H), 1.19, 1.16 [each s, 9 H, TBDMS-C(CH3)3], 0.45, 0.43,
0.32, 0.30 (each s, 3 H, TBDMS-SiCH3).
14.5 (3 C, C-10), 13.0 [3 C, TIPS-CH(CH3)2], 10.5 (d, 1J119Sn,C-7
1H NMR (500 MHz, toluene-d8, 363 K): d = 5.06 (d [dd, 3J119Sn,H-2
=
3
1H NMR (500 MHz, toluene-d8, 373 K): d = 5.42 (dd, JH-2,H-3
=
27.57 Hz], 3JH-2,H-3 = 3.47 Hz, 1 H, H-2), 4.50 (br s, 1 H, H-3), 4.42–
4.29 (br m, 4 H, H-4, H-5, H-6, H-6¢), 1.87 (m [3J119Sn,H-8 ≈ 53 Hz],
3.13 Hz, 4JH-2,H-4 = 1.20 Hz, 1 H, H-2), 4.72 (br m, 1 H, H-4), 4.55–
4.46 (br m, 4 H, H-3, H-5, H-6, H-6¢), 4.49 (br s, 3 H, OMe), 1.40–
1.25 (21 H, TIPS H), 1.15, 1.14 (s, 18 H, TBDMS C(CH3)3), 0.40,
0.39, 0.32, 0.30 (s, 12 H, TBDMS SiCH3).
3
3JH-8,H-7 ≈ 8 Hz, JH-8,H-7¢ ≈ 8 Hz, 3JH-8,H-9 ≈ 7.5 Hz, 6 H, H-8), 1.61
(tq, 3JH-9,H-8 ≈ 7.5 Hz, 3JH-9,H-10 = 7.35 Hz, 6 H, H-9), 1.38–1.31 (m,
2
3
21 H, TIPS-H), 1.28 (2 br dd, JH-7,H-7¢ ≈ 8 Hz, JH-7,H-8 ≈ 8 Hz,
3JH-7¢H-8 ≈ 8 Hz, 6 H, H-7, H-7¢), 1.20, 1.18 [s, 18 H, TBDMS-
C(CH3)3], 1.15 (t, 3JH-10,H-9 = 7.35 Hz, 9 H, H-10), 0.37–0.34 (br s,
12 H, TBDMS-SiCH3).
13C NMR (125 MHz, toluene-d8, 243 K): d = 338.2 (1 C, Ccarbene),
225.7 (1 C, trans-CO), 217.9 (4 C, cis-CO), 159.2 (1 C, C-1), 102.4
(1 C, C-2), 81.9 (1 C, C-3), 69.4, (1 C, C-5), 68.4, 67.2 (2 C, C-4,
OMe), 62.6 (1 C, C-6), 27.1, 27.1 [6 C, TBDMS-C(CH3)3], 19.5 [2
C, TBDMS-C(CH3)3], 18.9, 18.9 [6 C, TIPS-CH(CH3)2], 13.5 [3 C,
TIPS-CH(CH)3)2], –2.9, –3.6, –3.6, –3.7 (4 C, TBDMS-SiCH3).
13C NMR (125 MHz, toluene-d8, 363 K): d = 163.6 (1 C, C-1),
114.9 (1 C, C-2), 81.5 (1 C, C-3), 70.2 (1 C, C-5), 68.1 (1 C, C-4),
63.7 (1 C, C-6) 30.1 ([d, 2J119Sn,C-8 = 20.94 Hz], 3 C, C-8), 28.2 ([d,
3J119Sn,C-9 = 53.33 Hz], 3 C, C-9), 27.1 [6 C, TBDMS-C(CH3)3],
19.1 [6 C, TIPS-CH(CH3)2], 14.3 (3 C, C-10), 13.6 [3 C, TIPS-
CH(CH3)2], 11.0 (d, 1J119Sn,C-7 = 337.45 Hz, 3 C, C-7), –3.0, –3.5,
–3.5, –3.8 (4 C, TBDMS-SiCH3).
MS–FAB: m/z (%) = 763.3 (<1) [M+ – H], 652.3 (<1) [M+ – 4 CO],
624.3 (100) [M+ – 5 CO], 581.2 (15.6), 567.2 (12.9), 493.2 (9.5),
457.3 (16.2), 425.3 (18.7), 267.1 (22.2), 237.1 (20.5).
Anal. Calcd for C34H60O10CrSi3: C, 53.38; H, 7.90. Found: C, 53.68;
H, 8.48.
MS–FAB: m/z (%) = 819.4 (1.9) [M+ – H], 763.4 (2.5), 647.3 (1.3),
589.2 (2.3), 547.3 (1.5), 291.2 (26.5), 235.0 (29.7), 185.1 (40.9),
177.0 (100).
Cyclopropyl Glycals 11–13; General Procedure
A soln of one of glycal carbene complexes 7–9 (0.20–0.60 mmol)
and methyl (E)-crotonate (1 equiv) in n-heptane (5–15 mL) was
warmed to 82 °C for 1.5–3 h (TLC monitoring); the color of the soln
changed from red to orange. After evaporation of the solvent, the
residue was purified by chromatography (silica gel, 3 °C, PE–Et2O,
see Table 3) to give first diastereomers a/b and then diastereomers
c/d of cyclopropyl glycals 11–13, as colorless oils. See Table 3 for
experimental details for the preparation of 11–13.
Pentacarbonyl{[2-deoxy-3,4-O-di(tert-butyldimethylsilyl)-6-O-
(triisopropylsilyl)-D-lyxo-hex-1-enopyranosyl](methoxy)car-
bene}chromium (9)
A 1.6 M soln of n-BuLi in n-hexane (1.92 mL, 3.07 mmol, 1.1 equiv)
was added dropwise to a stirring soln of 6 (2.26 g, 2.79 mmol) in
THF (40 mL) at –78 °C. After 90 min, the mixture was transferred
within 60 min to a Schlenk tube containing Cr(CO)6 (737.2 mg,
3.35 mmol, 1.2 equiv) and was stirred at –45 °C for 60 min. Then
the solvent was evaporated at 0 °C and replaced by CH2Cl2 (80 mL)
before [Me3O]+[BF4]– (495.5 mg, 3.35 mmol, 1.2 equiv) was added
to the stirring mixture. The mixture was allowed to warm to r.t. and
stirred for 2 h. The solvent was removed in vacuo, and the residue
was adsorbed on silica gel and purified by rapid column chromatog-
raphy (PE–CH2Cl2, 6:1) at 3 °C.
1,5-Anhydro-1-[8,9-trans-7-methoxy-8-(methoxycarbonyl)-9-
methylcyclopropyl]-2-deoxy-3,4,6-tri-O-(triisopropylsilyl)-D-
arabino-hex-1-enitol (11a–d)
1H NMR (500 MHz, CDCl3): d (11a) = 5.01 (dd, 3JH-2,H-3 = 5.17 Hz,
4JH-2,H-4 = 1.63 Hz, 1 H, H-2), 4.28 (ptt, 3JH-5,H-6 = 6.75 Hz, 3JH-5,H-6¢
=
6.26 Hz, 4JH-5,H-3 = 1.86 Hz, 3JH-5,H-4 = 1.73 Hz, 1 H, H-5), 4.20 (pq,
3
4
3JH-4,H-3 ≈ 2 Hz, JH-4,H-5 = 1.73 Hz, JH-4,H-2 = 1.63 Hz, 1 H, H-4),
Yield: 1.50 g (70%); dark red viscous oil.
3
3
4
4.11 (pdt, JH-3,H-2 = 5.17 Hz, JH-3,H-4 ≈ 2 Hz, JH-3,H-5 = 1.86 Hz, 1
H, H-3), 4.03 (dd, 2JH-6,H-6¢ = 10.53 Hz, 3JH-6,H-5 = 6.75 Hz, 1 H, H-
2
6), 3.90 (dd, JH-6¢,H-6 = 10.53 Hz, JH-6¢,H-5 = 6.26 Hz, 1 H, H-6¢),
1
2
IR (PE): 2064 (m, A1 ), 1961 (s, E), 1946 (vs, A1 ) cm–1.
3
3
1H NMR (500 MHz, toluene-d8, 243 K): d = 5.65 (pt, JH-2,H-3
=
3
3.61 (s, 3 H, COOCH3), 3.34 (s, 3 H, OCH3), 1.95 (dq, JH-9,H-8
=
2.21 Hz, 4JH-2,H-4 ≈ 2.2 Hz, 1 H, H-2), 4.76 (m, 3JH-4,H-5 ≈ 2 Hz, 1 H,
H-4), 4.67 (pt, 2JH-6,H-6¢ ≈ 9.5 Hz, 3JH-6,H-5 ≈ 9.5 Hz, 1 H, H-6), 4.54
3
(dd, JH-3,H-4 = 3.37 Hz, JH-3,H-2 = 2.21 Hz, 1 H, H-3), 4.56, 4.46
7.16 Hz, 3JH-9,H-10 = 6.26 Hz, 1 H, H-9), 1.65 (d, 3JH-8,H-9 = 7.16 Hz,
1 H, H-8), 1.21 (d, 3JH-10,H-9 = 6.26 Hz, 3 H, H-10), 1.12–0.95 (m, 63
H, TIPS-H).
3
2
3
3
(each dd, JH-6,H-6¢ ≈ 9.5, JH-5,H-6 ≈ 9.5 Hz, JH-5,H-6¢ = 4.85 Hz,
3JH-5,H-4 ≈ 2 Hz, 2 H, H-5, H6¢), 4.01 (s, 3 H, OMe), 1.40–1.28 (m,
21 H, TIPS-H), 1.26, 1.18 [s, 18 H, TBDMS-C(CH3)3], 0.54, 0.52,
0.31, 0.30 (s, 12 H, TBDMS-SiCH3).
13C NMR (125 MHz, CDCl3): d (11a) = 170.0 (1 C, CO), 147.7 (1
C, C-1), 101.3 (1 C, C-2), 80.9 (1 C, C-5), 71.3 (1 C, C-7), 69.8 (1
C, C-4), 66.4 (1 C, C-3), 61.4 (1 C, C-6), 55.5 (1 C, COOCH3), 51.4
(1 C, OCH3), 34.0 (1 C, C-8), 24.5 (1 C, C-9), 18.2–17.9 [18 C,
TIPS-CH(CH3)2], 12.5–12.3 [9 C, TIPS-CH(CH3)2], 10.8 (1 C, C-
10).
13C NMR (125 MHz, toluene-d8, 243 K): d = 333.2 (1 C, Ccarbene),
225.9 (1 C, trans-CO), 217.7 (4 C, cis-CO), 157.1 (1 C, C-1), 103.3
(1 C, C-2), 79.8 (1 C, C-3), 69.6, (1 C, C-5) 66.5, 66.0 (2 C, C-4,
OMe), 61.0 (1 C, C-6), 26.7 [6 C, TBDMS-C(CH3)3], 19.4 [2 C,
1H NMR (500 MHz, CDCl3): d (11b) = 5.02 (dd, 3JH-2,H-3 = 5.50 Hz,
4JH-2,H-4 = 1.65 Hz, 1 H, H-2), 4.31 (pdt, 3JH-5,H-6 ≈ 6 Hz, 3JH-5,H-6¢
≈
Table 3 Experimental Details for the Cyclopropanation Reactions of Glycal Carbene Complexes 7–9
Starting material Quantity used (mmol) Temp (°C)
Time (min)
Chromatography eluent Products
Yields (%)
31:13:9:7
45:18:7:5
47:<1:6:2
7
8
9
0.60
0.60
0.68
82
82
82
90
180
160
PE–Et2O, 10:1
PE–Et2O, 3:1
PE–Et2O, 5:1
11a,b,c,d
12a,b,c,d
13a,b,c,d
Synthesis 2008, No. 14, 2183–2190 © Thieme Stuttgart · New York

2188
F. Otto, K. H. Dötz
PAPER
4
6 Hz, 3JH-5,H-4 = 2.06 Hz, JH-5,H-3 ≈ 2 Hz, 1 H, H-5), 4.30 (m, 1 H,
=C(CH3)2), 26.8 (1 C, C-9), 18.8 (1 C, =C(CH3)2), 18.3, 18.2 [6 C,
TIPS-CH(CH3)2], 12.6 [3 C, TIPS-CH(CH3)2], 10.8 (1 C, C-10).
H-4), 4.14 (pdt, 3JH-3,H-2 = 5.50 Hz, 3JH-3,H-4 ≈ 2 Hz, 4JH-3,H-5 ≈ 2 Hz,
2
H-3), 4.11 (dd, JH-6,H-6¢ ≈ 11 Hz, JH-6,H-5 ≈ 6 Hz, 1 H, H-6), 3.63
3
3
1H NMR (500 MHz, benzene-d6): d (12b) = 5.17 (d, JH-2,H-3
=
2
(dd, JH-6¢,H-6 ≈ 11 Hz, JH-6¢,H-5 ≈ 6 Hz, 1 H, H-6¢), 3.62 (s, 3 H,
3
2.12 Hz, 1 H, H-2), 4.62 (dd, 3JH-3,H-4 = 7.13 Hz, 3JH-3,H-2 = 2.12 Hz,
1 H, H-3), 3.97 (dd, 3JH-4H-5 = 10.28 Hz, 3JH-4,H-3 = 7.13 Hz, 1 H, H-
4), 3.93 (2JH-6e,H-6a = 10.28 Hz, 3JH-6e,H-5 = 5.27 Hz, 1 H, H-6e), 3.83
3
COOCH3), 3.35 (s, 3 H, OCH3), 1.79 (dq, JH-9,H-8 = 6.86 Hz,
3JH-9,H-10 = 6.26 Hz, 1 H, H-9), 1.61 (d, 3JH-8,H-9 = 6.86 Hz, 1 H, H-
3
8), 1.21 (d, JH-10,H-9 = 6.26 Hz, 1 H, H-10), 1.12–0.95 (m, 63 H,
TIPS-H).
3
3
3
(ptd, JH-5,H-4 = 10.28 Hz, JH-5,H-6a = 10.27 Hz, JH-5,H-6e = 5.27 Hz,
1 H, H-5), 3.75 (pt, 2JH-6a,H-6e = 10.28 Hz, 3JH-6a,H-5 = 10.27 Hz, 1 H,
H-6a), 3.40 (s, 3 H, COOCH3), 3.24 (s, 3 H, OCH3), 2.19 (dq,
13C NMR (125 MHz, CDCl3): d (11b) = 170.3 (1 C, CO), 147.7 (1
C, C-1), 102.2 (1 C, C-2), 80.3 (1 C, C-5), 71.8 (1 C, C-7), 68.9 (1
C, C-4), 66.2 (1 C, C-3), 61.1 (1 C, C-6), 55.4 (1 C, COOCH3), 51.3
(1 C, OCH3), 33.3 (1 C, C-8), 25.3 (1 C, C-9), 18.2–17.9 [18 C,
TIPS-CH(CH3)2], 12.5–12.3 [9 C, TIPS-CH3)2], 10.8 (1 C, C-10).
3JH-9,H-8 = 6.95 Hz, 3JH-9,H-10 = 6.26 Hz, 1 H, H-9), 1.79 (d, 3JH-8,H-9
=
6.95 Hz, 1 H, H-8), 1.45, 1.29 (s, 3 H, CH3), 1.24–1.10 (m, 21 H,
TIPS-H), 1.06 (d, 3JH-10,H-9 = 6.26 Hz).
13C NMR (125 MHz, benzene-d6): d (12b) = 170.0 (1 C, CO), 149.6
(1 C, C-1), 106.9 (1 C, C-2), 99.5 (1 C, =CMe2), 73.7 (1 C, C-4),
70.9 (1 C, C-7), 70.2, 69.1 (2 C, C-3, C-5), 62.0 (1 C, C-6), 55.5 (1
C, COOCH3), 51.2 (1 C, OCH3), 34.5 (1 C, C-8), 29.2 (1 C,
=C(CH3)2), 25.6 (1 C, C-9), 18.8 (1 C, =C(CH3)2), 18.3, 18.2, 17.9
[6 C, TIPS-CH(CH3)2], 12.7 [3 C, TIPS-CH(CH3)2], 10.8 (1 C, C-
10).
1H NMR (500 MHz, CDCl3): d (11c) = 5.08 (dd, 3JH-2,H-3 = 5.19 Hz,
4JH-2,H-4 = 1.60 Hz, 1 H, H-2), 4.36–4.29 (m, 1 H, H-5), 4.10–4.04
3
(m, 1 H, H-4), 4.08 (pdt, JH-3,H-2 = 5.19 Hz, JH-3,H-4 ≈ 2 Hz,
3
4JH-3,H-5 ≈ 2 Hz, 1 H, H-3), 3.98 (dd, 2JH-6,H-6¢ = 10.11 Hz, 3JH-6,H-5
=
=
2
7.62 Hz, 1 H, H-6), 3.85 (dd, JH-6¢H-6 = 10.11 Hz, JH-6¢H-5
3
4.87 Hz, 1 H, H-6¢), 3.69 (s, 3 H, COOCH3), 3.16 (s, 3 H, OCH3),
3
3
2.05 (dq, JH-9,H-8 ≈ 7 Hz, JH-9,H-10 ≈ 6.5 Hz, 1 H, H-9), 2.03 (d,
3JH-8,H-9 ≈ 7 Hz, 1 H, H-8), 1.10–0.97 (m, 66 H, H-10, TIPS-H).
3
1H NMR (500 MHz, benzene-d6): d (12c) = 5.30 (d, JH-2,H-3
=
2.18 Hz, 1 H, H-2), 4.61 (dd, 3JH-3,H-4 = 7.05 Hz, 3JH-3,H-2 = 2.18 Hz,
1 H, H-3), 3.92–3.87 (m, 1 H, H-4), 3.78 (dd, 2JH-6e,H-6a ≈ 10 Hz,
3JH-6e,H-5 ≈ 5 Hz, 1 H, H-6e), 3.67–3.58 (m, 2 H, H-5, H-6a), 3.44 (s,
3 H, COOCH3), 3.31 (s, 3 H, OCH3), 2.42 (dq, 3JH-9,H-8 = 7.15 Hz,
13C NMR (125 MHz, CDCl3): d (11c) = 170.7 (1 C, CO), 147.3 (1
C, C-1), 100.3 (1 C, C-2), 81.5 (1 C, C-5), 72.7 (1 C, C-7), 69.6 (1
C, C-4), 65.9 (1 C, C-3), 61.5 (1 C, C-6), 55.3 (1 C, COOCH3), 51.8
(1 C, OCH3), 30.2 (1 C, C-8), 27.1 (1 C, C-9), 18.2–17.9 [18 C,
TIPS-CH(CH3)2), 12.4–12.2 [9 C, TIPS-CH(CH3)2], 11.9 (1 C, C-
10).
3
3JH-9,H-10 = 6.46 Hz, 1 H, H-9), 2.25 (d, JH-8,H-9 = 7.15 Hz, 1 H, H-
8), 1.46, 1.26 (s, 6 H, CH3), 1.24–1.08 (m, 21 H, TIPS-H), 0.91 (d,
3JH-10,H-9 = 6.46 Hz, 3 H, H-10).
1H NMR (500 MHz, CDCl3): d (11d) = 5.10 (dd, 3JH-2,H-3 = 5.38 Hz,
3JH-2,H-4 = 1.67 Hz, 1 H, H-2), 4.36–4.29 (m, 1 H, H-5), 4.10–4.04
13C NMR (125 MHz, benzene-d6): d (12c) = 169.3 (1 C, CO), 149.3
(1 C, C-1), 105.7 (1 C, C-2), 99.5 (1 C, =CMe2), 73.9 (1 C, C-4),
71.6 (1 C, C-7), 70.0, 69.1 (2 C, C-3, C-5), 61.7 (1 C, C-6), 55.5 (1
C, COOCH3), 51.4 (1 C, OCH3), 31.0 (1 C, C-8), 29.2 (1 C,
=C(CH3)2), 27.1 (1 C, C-9), 18.3–17.9 [6 C, TIPS-CH(CH3)2],
12.8–12.6 [3 C, TIPS-CH(CH3)2], 11.9 (1 C, C-10).
3
(m, 1 H, H-4), 4.05 (pdt, 3JH-3,H-2 = 5.38 Hz, 3JH-3,H-4 ≈ 2 Hz, 4JH-3,H-5
2 Hz, 1 H, H-3), 3.94 (dd, 2JH-6,H-6¢ = 10.88 Hz, 3JH-6,H-5 = 7.29 Hz, 1
≈
2
3
H, H-6), 3.87 (dd, JH-6¢H-6 = 10.88 Hz, JH-6¢H-5 = 5.38 Hz, 1 H, H-
6¢), 3.69 (s, 3 H, COOCH3), 3.17 (s, 3 H, OCH3), 2.02 (dq,
3JH-9,H-8 = 6.79 Hz, 3JH-9,H-10 ≈ 6.5 Hz, 1 H, H-9), 1.89 (d, 3JH-8,H-9
6.79 Hz, 1 H, H-8), 1.10–0.97 (m, 66 H, H-10, TIPS-H).
=
1H NMR (500 MHz, benzene-d6): d (12d) = 5.24 (d, JH-2,H-3
=
1.99 Hz, 1 H, H-2), 4.59 (dd, 3JH-3,H-4 = 7.25 Hz, 3JH-3,H-2 = 1.99 Hz,
1 H, H-3), 3.92–3.87 (m, 1 H, H-4), 3.75 (dd, 2JH-6e,H-6a ≈ 10 Hz,
3JH-6e,H-5 ≈ 5 Hz, 1 H, H-6e), 3.67–3.58 (m, 2 H, H-5, H-6a), 3.43 (s,
3 H, COOCH3), 3.30 (s, 3 H, OCH3), 2.36 (dq, 3JH-9,H-8 = 7.06 Hz,
13C NMR (125 MHz, CDCl3): d (11d) = 170.6 (1 C, CO), 147.1 (1
C, C-1), 100.8 (1 C, C-2), 81.4 (1 C, C-5), 72.9 (1 C, C-7), 69.2 (1
C, C-4), 65.9 (1 C, C-3), 61.8 (1 C, C-6), 55.2 (1 C, COOCH3), 51.8
(1 C, OCH3), 30.7 (1 C, C-8), 27.2 (1 C, C-9), 18.2–17.9 [18 C,
TIPS-CH(CH3)2], 12.4–12.2 [9 C, TIPS-CH(CH3)2], 11.9 (1 C, C-
10).
3
3JH-9,H-10 = 6.46 Hz, 1 H, H-9), 2.05 (d, JH-8,H-9 = 7.06 Hz, 1 H, H-
8), 1.46, 1.26 (s, 6 H, CH3), 1.24–1.08 (m, 21 H, TIPS-H), 0.98 (d,
3JH-10,H-9 = 6.46 Hz, 3 H, H-10).
MS–FAB (11a/11b): m/z (%) = 756.5 (32.7) [M+], 713.4 (80.7),
583.3 (71.5), 551.3 (100), 385.3 (93.1).
13C NMR (125 MHz, benzene-d6): d (12d) = 169.5 (1 C, CO), 149.3
(1 C, C-1), 106.2 (1 C, C-2), 96.1 (1 C, =CMe2), 73.8 (1 C, C-4),
71.6 (1 C, C-7), 70.5, 68.8 (2 C, C-3, C-5), 61.8 (1 C, C-6), 55.6 (1
C, COOCH3), 51.4 (1 C, OCH3), 32.4 (1 C, C-8), 29.2 (1 C,
=C(CH3)2), 26.5 (1 C, C-9), 18.3–17.9 [6 C, TIPS CH(CH3)2], 12.8–
12.6 [3 C, TIPS-CH(CH3)2], 11.9 (1 C, C-10).
MS (EI, 70 eV) (11c/11d): m/z (%) = 756.5 (100) [M+], 713.4
(38.4), 408.2 (12.3), 365.1 (26.3), 395.2 (11.8), 385.2 (34.1)], 157.1
(41.7), 115.1 (52.5), 87.0 (21.9).
1,5-Anhydro-1-[8,9-trans-7-methoxy-8-(methoxycarbonyl)-9-
methylcyclopropyl]-2-deoxy-4,6-O-isopropylidene-3-O-(triiso-
propylsilyl)-D-arabino-hex-1-enitol (12a–d)
MS (EI, 70 eV) (12a/12b): m/z (%) = 484.3 (79.1) [M+], 441.2
(100), 409.2 (20.2), 383.2 (34.5), 323.1 (25.9), 199.1 (22.4), 143.0
(23.6).
3
1H NMR (500 MHz, benzene-d6): d (12a) = 5.18 (d, JH-2,H-3
=
HRMS–FAB (12a/12b): m/z calcd for C25H44O7Si3: 484.2856;
found: 484.28605.
2.22 Hz, 1 H, H-2), 4.64 (dd, 3JH-3,H-4 = 7.20 Hz, 3JH-3,H-2 = 2.22 Hz,
1 H, H-3), 4.00 (dd, 3JH-4,H-5 = 10.07 Hz, 3JH-4,H-3 = 7.20 Hz, 1 H, H-
MS (EI, 70 eV) (12c/12d): m/z (%) = 484.3 (74.0) [M+], 441.2
(93.6), 409.3 (24.8), 383.2 (43.8), 323.2 (53.2), 199.1 (76.0), 149.3
(100), 143.0 (62.0).
2
3
4), 3.90 (dd, JH-6e,H-6a = 9.91 Hz, JH-6e,H-5 = 4.95 Hz, H-6e), 3.84
(ptd, 3HH-5,H-4 = 10.07 Hz, 3JH-5,H-6a = 10.02 Hz, 3JH-5,H-6e = 4.95 Hz,
3
2
1 H, H-5), 3.81 (pt, JH-6a,H-5 = 10.02 Hz, JH-6a,H-6e = 9.91 Hz, 1 H,
H-6a), 3.40 (s, 3 H, COOCH3), 3.28 (s, 3 H, OCH3), 2.11 (dq,
=
HRMS–FAB (12c/12d): m/z calcd for C25H44O7Si3: 484.2856;
found: 484.28653.
3JH-9,H-8 = 6.76 Hz, 3JH-9,H-10 = 6.46 Hz, 1 H, H-9), 1.77 (d, 3JH-8,H-9
6.76 Hz, 1 H, H-8), 1.46, 1.27 (s, 6 H, CH3), 1.25–1.14 (m, 21 H,
TIPS-H), 1.08 (d, 3JH-10,H-9 = 6.46 Hz, 3 H, H-10).
1,5-Anhydro-3,4-di-O-(tert-butyldimethylsilyl)-1-[8,9-trans-7-
methoxy-8-(methoxycarbonyl)-9-methylcyclopropyl]-2-deoxy-
D-lyxo-hex-1-enitol (13a–d)
13C NMR (125 MHz, benzene-d6): d (12a) = 170.4 (1 C, CO), 150.0
(1 C, C-1), 108.1 (1 C, C-2), 99.6 (1 C, =CMe2), 73.8 (1 C, C-4),
71.4 (1 C, C-7), 70.7, 69.0 (2 C, C-3, C-5), 62.0 (1 C, C-6), 55.6 (1
C, COOCH3), 51.2 (1 C, OCH3), 33.3 (1 C, C-8), 29.2 (1 C,
1H NMR (500 MHz, toluene-d8, 358 K): d (13a) = 5.09 (d, 3JH-2,H-3
3.63 Hz, 1 H, H-2), 4.55 (br, 1 H, H-3), 4.39–4.24 (br, 4 H, H-4, H-
=
Synthesis 2008, No. 14, 2183–2190 © Thieme Stuttgart · New York

PAPER
Diastereoselective Cyclopropanation of Electron-Deficient Alkenes
2189
5, H-6, H-6¢), 3.67 (s, 3 H, COOCH3), 3.58 (s, 3 H, OCH3), 2.14 (dq,
3
tion of the second band with PE–Et2O (1:1) afforded a mixture of
diastereomers 15a,b (2.4:1).
3
3JH-9,H-8 = 6.75 Hz, JH-9,H-10 ≈ 6.5 Hz, 1 H, H-9), 1.82 (d, JH-8,H-9
=
6.75 Hz, 1 H, H-8), 1.35–1.23 (m, 24 H, TIPS-H, H-10), 1.18, 1.15
[s, 18 H, TBDMS-C(CH3)3], 0.37, 0.36, 0.31, 0.29 (s, 12 H,
TBDMS-SiCH3).
Yield: 12.4 mg (5%); colorless oil.
1,5-Anhydro-2-deoxy-4,6-O-isopropylidene-1-(6-methoxy-3-
oxo-2-oxabicyclo[3.1.0]hex-6-yl)-3-O-(triisopropylsilyl)-D-ara-
bino-hex-1-enitol (15a,b)
13C NMR (125 MHz, toluene-d8, 358 K): d (13a) = 170.9 (1 C, CO),
150.7 (1 C, C-1), 105.3 (1 C, C-2), 81.3 (1 C, C-5), 72.4 (1 C, C-7),
69.4, 68.2 (2 C, C-4, C-3), 63.1 (1 C, C-6), 56.5 (1 C, COOCH3),
51.6 (1 C, OCH3), 34.2 (1 C, C-8), 27.3 (1 C, C-9), 27.0 [6 C,
TBDMS-C(CH3)3], 190.0, 18.9, 18.9 [8 C, TBDMS-C(CH3)3,
TIPS-CH(CH3)2], 13.4 [3 C, TIPS-CH(CH3)2], 11.4 (1 C, C-10),
–3.0, –3.6, –3.7, –4.0 (4 C, TBDMS-SiCH3).
1H NMR (500 MHz, CDCl3): d (15a) = 4.94 (d, 3JH-2,H-3 = 2.12 Hz,
1 H, H-2), 4.45 (dd, 3JH-3,H-4 ≈ 10 Hz, 3JH-3,H-2 = 2.12 Hz, 1 H, H-3),
2
4.43–4.98 (m, 2 H, H-10, H-10¢), 3.88 (dd, JH-6e,H-6a = 10.76 Hz,
3JH-6e,H-5 = 5.58 Hz, 1 H, H-6e), 3.76 (pt, 3JH-4,H-5 = 10.33 Hz, 3JH-4,H-3
≈
=
=
2
10 Hz, 1 H, H-4), 3.72 (pt, JH-6a,H-6e = 10.76 Hz, JH-6a,H-5
3
3
10.40 Hz, 1 H, H-6a), 3.64 (ptd, JH-5,H-6a = 10.40 Hz, JH-5,H-4
3
1H NMR (500 MHz, toluene-d8, 358 K): d (13b, trace) = 5.25 (d,
3JH-2,H-3 ≈ 2.5 Hz, 1 H, H-2), 4.65 (br, 1 H, H-3), 4.39–4.24 (br, 4 H,
H-4, H-5, H-6, H-6¢), 3.72 (s, 3 H, COOCH3), 3.62 (s, 3 H, OCH3),
10.33 Hz, 3JH-5,H-6e = 5.58 Hz, 1 H, H-5), 3.43 (s, 3 H, OCH3), 2.68
3
3
(d, JH-8,H-9 = 6.97 Hz, 1 H, H-8), 2.46 (ddd, JH-9,H-8 = 6.97 Hz,
3JH-9,cis-H-10 = 4.60 Hz, 3JH-9,trans-H-10 = 2.26 Hz, 1 H, H-8), 1.48 [s, 3
H, =C(CH3)2], 1.37 [s, 3 H, =C(CH3)2], 1.12–0.98 (m, 21 H, TIPS-H).
3
1.86 (d, JH-8,H-9 = 7.13 Hz, 1 H, H-8), 0.40 (s, 3 H, TBDMS-
SiCH3).
13C NMR (125 MHz, CDCl3): d (15a) = 173.4 (1 C, CO), 147.2 (1
C, C-1), 103.6 (1 C, C-2), 99.6 (1 C, =CMe2), 73.1 (1 C, C-4), 70.3,
68.0 (2 C, C-3, C-5), 65.6 (1 C, C-10), 65.0 (1 C, C-7), 61.6 (1 C,
C-6), 56.5 (1 C, OMe), 31.5 (1 C, C-9), 29.2 (1 C, C-8), 28.9, 18.9
[2 C, =C(CH3)2], 18.9, 18.0, 17.9 [6 C, TIPS-CH(CH3)2], 12.2 [3 C,
TIPS-CH(CH3)2].
1H NMR (125 MHz, toluene-d8, 358 K): d (13c) = 5.27 (d, 3JH-2,H-3
=
3.89 Hz, 1 H, H-2), 4.54 (pt, 3JH-3,H-4 ≈ 3.5 Hz, 3JH-3,H-2 = 3.89 Hz, 1
H, H-3), 4.47–4.25 (m, 4 H, H-4, H-5, H-6, H-6¢), 3.64 (s, 3 H,
3
COOCH3), 3.49 (s, 3 H, OCH3), 2.44 (dq, JH-9,H-8 = 7.14 Hz,
3JH-9,H-10 ≈ 6.5 Hz, 1 H, H-9), 2.35 (d, 3JH-8,H-9 = 7.14 Hz, 1 H, H-8),
1.62–1.28 (m, 24 H, TIPS-H, H-10), 1.18–1.14 [m, 18 H, TBDMS-
C(CH3)3], 0.34, 0.33, 0.32, 0.31 (s, 12 H, TBDMS-SiCH3).
1H NMR (500 MHz, CDCl3): d (15b) = 4.70 (d, 3JH-2,H-3 = 2.54 Hz,
1 H, H-2), 4.43 (dd, 3JH-3,H-4 ≈ 10 Hz, 3JH-3,H-2 = 2.54 Hz, 1 H, H-3),
2
4.43–4.98 (m, 2 H, H-10, H-10¢), 3.87 (dd, JH-6e,H-6a = 10.23 Hz,
13C NMR (125 MHz, toluene-d8, r.t.): d (13c) = 170.1 (1 C, CO),
149.3 (1 C, C-1), 72.6 (1 C, C-7).
3JH-6e,H-5 = 5.47 Hz, 1 H, H-6e), 3.76 (pt, 3JH-4,H-5 = 10.15 Hz, 3JH-4,H-3
≈
=
=
13C NMR (125 MHz, toluene-d8, 358 K): d (13c) = 103.5 (1 C, C-
2), 81.7 (1 C, C-5), 69.9, 67.8 (2 C, C-3, C-4), 63.1 (1 C, C-6), 56.3
(1 C, COOCH3), 51.7 (1 C, CH3), 33.0 (1 C, C-8), 27.5 (1 C, C-9),
27.2–26.9 [6 C, TBDMS-C(CH3)3], 19.1–18.8 [6 C, TIPS-
CH(CH3)2], 13.6–13.2 [4 C, TIPS-CH(CH3)2, C-10], –3.0, –3.5,
–3.5, –4.0 (4 C, TBDMS-SiCH3).
2
10 Hz, 1 H, H-4), 3.71 (pt, JH-6a,H-6e = 10.23 Hz, JH-6a,H-5
3
3
10.10 Hz, 1 H, H-6a), 3.66 (ptd, JH-5,H-4 = 10.15 Hz, JH-5,H-6a
3
10.10 Hz, 3JH-5,H-6e = 5.47 Hz, 1 H, H-5), 3.44 (s, 3 H, OCH3), 2.61
3
3
(d, JH-8,H-9 = 6.97 Hz, 1 H, H-8), 2.54 (ddd, JH-9,H-8 = 6.97 Hz,
3JH-9,cis-H-10 = 5.15 Hz, 3JH-9,trans-H-10 = 1.42 Hz, 1 H, H-9), 1.46 [s, 3
H, =C(CH3)2], 1.37 [s, 3 H, =C(CH3)2], 1.12–0.98 (m, 21 H, TIPS-H).
1H NMR (500 MHz, toluene-d8, 358 K): d (13d) = 5.27 (d, 3JH-2,H-3
=
13C NMR (125 MHz, CDCl3): d (15b) = 173.4 (1 C, CO), 147.2 (1
C, C-1), 103.5 (1 C, C-2), 99.6 (1 C, =CMe2), 73.0 (1 C, C-4), 70.3,
67.9 (2 C, C-3, C-5), 65.6 (1 C, C-10), 65.3 (1 C, C-7), 61.6 (1 C,
C-6), 56.8 (1 C, OMe), 30.6 (1 C, C-9), 30.3 (1 C, C-8), 28.9, 18.9
[2 C, =C(CH3)2], 18.9, 18.0, 17.9 [6 C, TIPS CH(CH3)2], 12.2 [3 C,
TIPS-CH(CH3)2].
3.77 Hz, 1 H, H-2), 4.59 (pt, 3JH-3,H-2 = 3.77 Hz, 3JH-3,H-4 ≈ 3.5 Hz, 1
H, H-3), 4.47–4.25 (m, 4 H, H-4, H-5, H-6, H-6¢), 3.66 (s, 3 H,
3
COOCH3), 3.51 (s, 3 H, OCH3), 2.44 (dq, JH-9,H-8 = 7.01 Hz,
3JH-9,H-10 ≈ 6.5 Hz, 1 H, H-9), 2.37 (d, 3JH-8,H-9 = 7.01 Hz, 1 H, H-8),
1.62–1.28 (m, 24 H, TIPS-H, H-10), 1.18–1.14 [m, 18 H, TBDMS-
C(CH3)3], 0.36, 0.34, 0.32, 0.31 (s, 12 H, TBDMS-SiCH3).
MS (EI, 70 eV) (15a/15b): m/z (%) = 468.3 (5.4) [M+], 453.3
(19.0), 439.3 (12.3), 425.3 (100).
13C NMR (125 MHz, toluene-d8, r.t.): d (13d) = 170.1 (1 C, CO),
149.7 (1 C, C-1), 73.0 (1 C, C-7).
HRMS–FAB (15a/15b): m/z calcd for C24H40O7Si: 468.2543;
found: 468.2539.
13C NMR (125 MHz, toluene-d8, 358 K): d (13d) = 103.5 (1 C, C-
2), 81.7 (1 C, C-5), 69.5, 68.3 (2 C, C-3, C-4), 63.2 (1 C, C-6), 56.3
(1 C, COOCH3), 51.7 (1 C, CH3), 32.7 (1 C, C-8), 27.6 (1 C, C-9),
27.2–26.9 [6 C, TBDMS-C(CH3)3], 27.2–26.9 [6 C, TBDMS-
C(CH3)3], 19.1–18.8 [6 C, TIPS-CH(CH3)2], 13.6–13.2 [4 C, TIPS-
CH(CH3)2, C-10], –3.1, –3.6, –3.7, –4.0 (4 C, TBDMS-SiCH3).
Acknowledgment
Financial support from the Deutsche Forschungsgemeinschaft (SFB
624) and the Fonds der Chemischen Industrie is gratefully acknow-
ledged.
MS (EI, 70 eV) (13a/13b): m/z (%) = 672.5 (7.9) [M+], 629.3
(12.5), 541.3 (35.2), 343.3 (14.0), 307.1 (100).
HRMS–FAB (13a/13b): m/z calcd for C34H68O7Si3: 672.4273;
found: 672.4272.
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