Stereoselective preparation of precursors of α-C-(1→3)- disaccharides

Article abstract of DOI:10.1135/cccc20051411

The stereoselectivity of cycloaddition of sugar-containing substituted 1-(thiazol-2-yl)but-2-en-1-ones 1 and vinyl ethers was studied using the achiral vinyl ether/chiral catalyst as well as the chiral vinyl ether/achiral catalyst combinations. It has bee

Full text of DOI:10.1135/cccc20051411

Precursors of α-C-(1→3)-Disaccharides
1411
STEREOSELECTIVE PREPARATION OF PRECURSORS OF
α-C-(1→3)-DISACCHARIDES
a
Petr ŠTĚPÁNEK , Ondřej VÍCHb1, Lukáš WERNERb2, Ladislav KNIEŽOb3,*,
c
d
Hana DVOŘÁKOVÁ and Pavel VOJTÍŠEK
a
Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic,
Flemingovo nám. 2, 166 10 Prague 6, Czech Republic; e-mail: pstepane@centrum.cz
Department of Chemistry of Natural Compounds, Institute of Chemical Technology, Prague,
Technická 5, 166 28 Prague 6, Czech Republic; e-mail: 1 ondrej.vich@vscht.cz, 2 lukas.werner@vscht.cz,
b
3
ladislav.kniezo@vscht.cz
c
NMR Laboratory, Institute of Chemical Technology, Prague,
Technická 5, 166 28 Prague 6, Czech Republic; e-mail: hana.dvorakova@vscht.cz
Department of Inorganic Chemistry, Charles University,
d
128 40 Prague 2, Czech Republic; e-mail: pavojt@natur.cuni.cz
Received April 11, 2005
Accepted Jun e 6, 2005
Th e stereoselectivity of cycloaddition of sugar-con tain in g substituted 1-(th iazol-2-yl)but-
2-en -1-on es 1 an d vin yl eth ers was studied usin g th e ach iral vin yl eth er/ch iral catalyst as
well as th e ch iral vin yl eth er/ach iral catalyst com bin ation s. It h as been sh own th at
Eu(fod)3-catalyzed cycloaddition of oxadien es 1a–1e with th e ch iral vin yl eth ers 9 an d 10
affords stereoselectively alm ost pure cycloadducts 11a–11e an d 12a–12e, respectively. Th e
obtain ed cycloadducts are suitable precursors for th e syn th esis of α-C-(1→3)-disacch arides,
con tain in g 2-deoxy-arabino-h exopyran ose m oiety of D- or L-con figuration .
Keyw ord s: Hetero-Diels–Alder reaction s; Cycloaddition s; Sacch arides; Carboh ydrates;
Disacch arides; Carba-an alogues; Stereoselective syn th esis; X-ray diffraction ; Th iazoles;
Dih ydropyran s; C-glycosides.
Th e cell-surface carboh ydrates play essen tial role in cell com m un ication
system an d can sign ifican tly in fluen ce m an y vital processes. It is assum ed
th at C-disacch arides, wh ich are an alogues of n atural disacch arides but in
wh ich th e glycosidic oxygen atom h as been substituted with a m eth ylen e
group m im ic well th e disacch aride structure but th ey resist acidic as well as
en zym e h ydrolysis. Th e C-disacch arides as disacch aride m im etics could
form n on h ydrolyzable epitopes of cell surface glycocon jugates, th us dis-
turbin g th eir in teraction s with protein s, or th ey could in h ibit th e en zym es
in volved in th e biosyn th esis of glycocon jugates. For th ese reason s, th ere is
Collect. Czech. Chem. Commun. (Vol. 70) (2005)
doi:10.1135/cccc20051411

1412
Štěpánek et al.:
an in creased in terest in th e search for n ew syn th etic path ways leadin g to
C-disacch arides an d in th e study of th eir properties1.
Recen tly we described a sh ort an d efficien t syn th esis of α-C-(1→3)-
disacch arides, con tain in g 2-deoxy-arabino-h exopyran ose m oiety2, in wh ich
th e key step was th e h etero-Diels–Alder reaction of eth yl vin yl eth er with
ch iral 1-oxa-1,3-butadien es 1a or 1b (see Sch em e 1). Un der catalysis with
Eu(fod)3 (Europium (III) tris(6,6,7,7,8,8,8-heptafluoro-2,2-dim ethyl-3,5-octane-
dion ate) th is cycloaddition was h igh ly endo- selective an d afforded a m ix-
ture of on ly two diastereoisom eric cycloadducts 2 an d 3 in th e ca 1:1 ratio.
With acetyl protectin g groups, th e obtain ed diastereoisom ers 2a an d 3a
were n ot separable by preparative ch rom atograph y on silica gel; h owever,
in th e case of ben zyl protectin g groups th e cycloadducts 2b an d 3b were
separated with out an y problem s an d each of th em was con verted in to th e
fin al α-C-(1→3)-disacch aride with D- (com poun d 4) or L- (com poun d 5)
con figuration of th e n ew deoxyh exopyran ose.
Th e n ecessary separation of th e obtain ed m ixture of diastereoisom ers
2 an d 3 is a weak poin t of th e m en tion ed syn th esis sign ifican tly lim itin g
a m ore gen eral utilization of th is path way because it can n ot be predicted
wh eth er oth er oxadien es 1, con tain in g m on osacch arides of oth er con figu-
ration or with oth er protectin g groups, will afford ch rom atograph ically well
R
N
OAc
S
O
AcO
AcO
OAc
O
O
AcO
AcO
R
N
OEt
OEt
OEt
2a, 2b
S
Eu(fod)3
4
O
OAc
R
N
1a, 1b
O
AcO
AcO
S
AcO
AcO
AcO
O
O
OEt
OEt
3a, 3b
5
OAc
O
OBn
O
AcO
AcO
BnO
BnO
a: R =
b: R =
AcO
BnO
SCHEME 1
Syn th etic route to α-C-(1→3)-disacch arides
Collect. Czech. Chem. Commun. (Vol. 70) (2005)

Precursors of α-C-(1→3)-Disaccharides
1413
separable cycloadducts. To avoid problem s associated with th e separation
of th e cycloadducts, we tried to study wh eth er th e cycloaddition could be
perform ed with even h igh er stereoselectivity, leadin g to on ly on e of th e
two endo-cycloadducts, eith er to com poun d 2 or 3.
Th e form ation of th e two cycloadducts 2 an d 3 in th e 1:1 ratio in dicates
th at in th e studied cycloaddition th e m on osacch aride m oiety presen t in th e
startin g oxadien e 1a or 1b h as practically n o ch iral in fluen ce. We can
th erefore assum e th at for th e facial stereoselectivity con trol of th e
cycloaddition on e could use procedures of classical en an tioselective syn th e-
sis, irrespective of wh eth er th e presen t addition al ch iral elem en t will form a
m atch ed or m ism atch ed pair with th e startin g ch iral oxadien e 1.
Th e en an tioselectivity of h etero-Diels–Alder reaction of structurally very
sim ilar oxadien es, i.e. β,γ-un saturated α-keto esters, h as already been stud-
ied. In th e reaction s of th ese oxadien es, h igh en an tioselectivity was
ach ieved by replacem en t of th e ester group by a ch iral auxiliary group3, us-
in g ch iral catalysis4,5 or ch iral en ol eth ers6. We decided to study wh eth er
also in th e case of oxadien es 1, con tain in g a th iazole rin g, th e facial
stereoselectivity of th e cycloaddition can be con trolled by th e ch iral cataly-
sis or by th e use of ch iral en ol eth ers.
Stereoselectivity of th e cycloaddition was studied with oxadien es 1a–1e
(see Sch em e 3) con tain in g m on osacch aride m oieties of various con figura-
tion s with various protectin g groups. Th e startin g oxadien es 1a–1e can be
easily obtain ed from th e correspon din g α-pyran osylpropen es; h owever, th e
situation is com plicated by th e fact th at ch rom atograph ic separation of
α-pyran osylpropen es from th e m in or β-epim ers is usually difficult. Purifica-
tion of α-pyran osylpropen es, required for th e syn th esis of oxadien es 1a an d
1b, is described in our previous paper2. Isopropyliden e-protected α-m an n o-
pyran osylpropen e, precursor of oxadien e 1e, is crystallin e an d can be sepa-
rated from th e m in or β-epim er by crystallization 7. On th e oth er h an d, isola-
tion of pure galactopyran osylpropen es, precursors of oxadien es 1c an d 1d ,
was n ot trivial. 1-(Tetra-O-acetyl-α-D-galactopyran osyl)prop-2-en e8 h as al-
ready been syn th esized from th e correspon din g pyran osyl brom ide an d al-
lylic sulfide in th e presen ce of h exabutyldistan n an e un der ph otolytic con -
dition s, h owever, th e description in th e experim en tal part of th e cited pa-
per8 does n ot m en tion possible con tam in ation with β-epim er. An even
m uch sim pler syn th esis of th is propen e by reaction of pen ta-O-acetyl-
D-galactose with com m ercial allyltrim eth ylsilan e un der catalysis with
BF3·Et2O is described9. Th e auth ors state th at after 48 h in aceton itrile at
4 °C th e desired α-epim er is obtain ed in 80% yield, th e stereoselectivity
bein g 95:5. In our h an ds, th e reaction un der th ese con dition s gave n eith er
Collect. Czech. Chem. Commun. (Vol. 70) (2005)

1414
Štěpánek et al.:
th e stated yield n or th e selectivity. Fin ally we foun d th at th e en tirely pure
α-epim er can be easily obtain ed by th e followin g efficien t procedure.
Heatin g at reflux a solution of pen ta-O-acetyl-D-galactose, allyltrim eth yl-
silan e an d BF3·Et2O in aceton itrile for 4 h gave a 6:1 m ixture of α- an d
β-epim ers of 1-(tetra-O-acetyl-D-galactopyran osyl)prop-2-en e in 98% yield
(Sch em e 2). Zem plén deacetylation afforded quan titatively th e sam e m ix-
ture of epim eric 1-(D-galactopyran osyl)prop-2-en es, wh ich was dissolved in
eth an ol an d treated with eth er to turbidity, affordin g in 60% yield crystal-
lin e, com pletely pure α-epim er 6, m eltin g at 134–135 °C, wh ich , to our
kn owledge, h as n ot been so far described. Its acetylation an d ben zylation
afforded in h igh yield an d purity th e respective com poun ds 7 an d 8, pre-
cursors for th e syn th esis of oxadien es 1c an d 1d .
To obtain th e oxadien es 1c–1e, th e prepared α-galactopyran osylpropen es
7 an d 8 as well as th e isopropyliden e-protected α-m an n opyran osyl-
propen e7, were subjected to ozon olysis. We foun d th at ozon ides, form ed
from α-galactopyran osylpropen es with acetyl or isopropyliden e protectin g
groups, can be decom posed10 with stabilized 2-ph osph oran yliden e-
1-(th iazol-2-yl)eth an -1-on e11 with direct form ation of oxadien es 1c or 1e.
With th e ben zyl protectin g groups, th is procedure gave on ly a m ixture of
products an d it was n ecessary to decom pose th e arisin g ozon ide with
dim eth yl sulfide to give th e aldeh yde th at subsequen tly, in a Wittig reac-
tion with th e above m en tion ed ylide, gave oxadien e 1d .
OAc
OAc
OH
5'
6'
4'
O
(i)
O
(ii)
AcO
AcO
AcO
AcO
O
HO
HO
2'
1'
AcO
AcO
6 : 1
3'
HO
OAc
1
3
6
2
(iii)
(iv)
OAc
OBn
O
O
(vi)
(v)
AcO
AcO
BnO
BnO
1d
1c
AcO
BnO
7
8
(i) allyltrimethylsilane, BF3·Et2O, MeCN, reflux, 4 h
(ii) 1. MeONa/MeOH, 2. crystalization from EtOH/Et2O; (iii) Ac2O, pyridine; (iv) NaH, BnBr, DMF
(v) 1. O3, CH2Cl2, 2. 2-phosphoranylidene-1-(thiazol-2-yl)ethan-1-one
(vi) 1. O3, CH2Cl2, 2. Me2S, 3. 2-phosphoranylidene-1-(thiazol-2-yl)ethan-1-one
SCHEME 2
Syn th esis of 1-(α-D-galactopyran osyl)prop-2-en es
Collect. Czech. Chem. Commun. (Vol. 70) (2005)

Precursors of α-C-(1→3)-Disaccharides
1415
Th e trans-con figuration at th e C=C bon d in oxadien es 1c an d 1e was un -
equivocally con firm ed on th e basis of vicin al in teraction of olefin ic proton s
1
in th e H NMR spectrum . On th e oth er h an d, it was n ot possible to con firm
th e trans-con figuration in 1d directly from th e couplin g con stan ts because
th e pertin en t sign als were overlapped by sign als of arom atic proton s. Th e
trans-con figuration of th is com poun d was assign ed in an in direct way, on
th e basis of th e fact th at th e cycloaddition with eth yl vin yl eth er afforded
on ly two perben zylated cycloadducts 2 an d 3 of th e sam e con figuration as
th e peracetylated cycloadducts arisin g from oxadien e 1c in wh ich th e
trans-con figuration h ad already been con firm ed.
First, we tried to affect th e cycloaddition stereoselectivity by th e use of
ch iral catalysts. To be able to com pare th e effectivity an d stereoselectivity
of various catalysts, we perform ed several reaction s of oxadien e 1b un der
iden tical con dition s, i.e. with 10 m ole % of catalyst, in dich lorom eth an e
solution an d at room tem perature. Firstly, we used both en an tiom ers
of Eu(h fc)3 (Europium (III) tris[3-(h eptafluoropropylh ydroxym eth ylen e)-
cam ph orate]) in stead of th e ach iral Eu(fod)3. Un fortun ately, th is did n ot
lead to an y m arked in crease in reaction stereoselectivity: th e ratio of th e
two cycloadducts ch an ged on ly in sign ifican tly. Moreover, in both cases we
observed a sign ifican t prolon gation of th e reaction tim e (from 7 to about
1
16 h ) an d th e H NMR spectrum of th e reaction m ixture exh ibited also n ew
sign als probably correspon din g to th e trans-isom ers (ca 15%).
As furth er catalysts we tried th e derivatives of an oth er lan th an ide, ytter-
bium . Th e reaction of oxadien es 1 in th e presen ce of ach iral Yb(OTf)3 was
slower th an with Eu(fod)3 (it was com plete on ly after 4 days) an d th e
1H NMR spectrum again con tain ed also sign als correspon din g to supposed
trans-cycloadducts. In spite of th is we tried to in fluen ce th e facial stereo-
selectivity by th e use of ch iral catalysts th at h ad been successfully em -
ployed in cycloaddition s by Kobayash i12 an d Nakagawa13 an d wh ich are
form ed in situ from Yb(OTf)3, a tertiary am in e an d biaryl ch iral ligan ds. As
ch iral ligan ds we used both en an tiom ers of 1,1′-bin aph th alen e-2,2′-diol,
(S)-2′-benzamido-1,1′-binaphthalen-2-ol and (S)-N,N′-dibenzoyl-1,1′-binaphthalene-
2,2′-diam in e an d th e selected tertiary am in e was diisopropyleth ylam in e.
Un fortun ately, even th e use of th ese catalysts did n ot lead to sign ifican t
ch an ges in stereoselectivity, th e cycloaddition bein g even slower th an th at
with Yb(OTf)3.
As foun d in th e literature, cycloaddition s of th e structurally sim ilar
β,γ-un saturated α-keto esters led to outstan din g en an tioselectivity with cat-
alysts based on th e ch iral bisoxazolin e copper(II) com plexes, particularly
with tert-butyl-substituted bisoxazolin e copper(II) triflate4,5 or in dan e-
Collect. Czech. Chem. Commun. (Vol. 70) (2005)

1416
Štěpánek et al.:
derived bisoxazolin e copper(II) triflate14. Usin g Cu(OTf)2 we observed about
th e sam e activity as Yb(OTf)3 (un der th e sam e con dition s, th e reaction was
com pleted after about 6 days an d th e reaction m ixture again con tain ed also
supposed trans-cycloadducts). With ch iral tert-butyl-substituted bis-
oxazolin e copper(II) triflate4,5 th e reaction m ixture after 9 days still con -
tain ed 60% of th e startin g oxadien e 1b, m oreover, th e arisin g product
again sh owed n o sign ifican t ch an ge in th e facial stereoselectivity.
As th e m en tion ed ch iral catalysts h ave n ot afforded th e desired stereo-
selectivity en h an cem en t, we turn ed our atten tion to th e use of ch iral en ol
eth ers. Th e literature data sh ow th at in cycloaddition s of β,γ-un saturated
α-keto esters, th e best results were obtain ed by Dujardin 6 et al. with ch iral
vin yl eth ers 9 an d 10 (Sch em e 3) wh ich can be easily obtain ed from ch eap
an d com m ercially accessible en an tiom ers of m an delic acid. Th erefore, we
syn th esized th ese ch iral vin yl eth ers an d to our deligh t we foun d th at th eir
cycloaddition with th iazole-substituted oxadien es 1b is h igh ly stereo-
selective, affordin g on ly on e diastereoisom er in alm ost pure form .
R
N
S
O
COOCH3
O
Ph
Eu(fod)3
9
O
O
COOCH3
R
N
11a-11e
2
Ph
1
4
S
3
R
N
S
O
O
COOCH3
1a-1e
O
Ph
10
COOCH3
12a-12e
Ph
OAc
OBn
AcO OAc
AcO
6'
4'
5'
2'
O
O
O
AcO
BnO
BnO
a: R =
b: R =
c: R =
AcO
1'
3'
AcO
BnO
AcO
BnO
OBn
O
O
O
O
d: R =
e: R =
O
BnO
O
BnO
SCHEME 3
Cycloaddition of substituted oxadien es with ch iral vin yl eth ers
Collect. Czech. Chem. Commun. (Vol. 70) (2005)

Precursors of α-C-(1→3)-Disaccharides
1417
Th e sim ilar stereoselectivity sh owed reaction s with all oth er startin g
oxadien es 1a–1e. Th eir cycloaddition s with th e ch iral vin yl eth er 9 un der
catalysis with Eu(fod)3 afforded diastereoisom ers 11a–11e as prin cipal prod-
ucts an d diastereoisom ers 12a–12e as m in or products. On th e oth er h an d
th e cycloaddition with th e vin yl eth er 10 gave, with practically th e sam e
selectivity, diastereoisom ers 12a–12e as th e m ain products (see Table I).
Th e obtain ed results con firm th at th e m on osacch aride m oieties in th e start-
in g oxadien es 1a–1e in deed h ave n o ch iral in fluen ce in th is cycloaddition
an d th e ch iral vin yl eth ers 9 an d 10 do n ot form m atch ed an d m ism atch ed
pairs with th e startin g oxadien es.
All th e isolated cycloadducts 11a–11e an d 12a–12e exh ibited a stron g
NOEs between proton s H-2 an d H-4 on th e 3,4-dih ydro-2H-pyran rin g th at
con firm th eir relative cis-con figuration . Th us, cycloadducts 11a–11e an d
2
12a–12e, sim ilarly to cycloadducts 2 an d 3 , m ust differ in th e absolute
con figuration at th e ch iral atom s C-2 an d C-4 of th e 3,4-dih ydro-2H-pyran
rin g.
To assign un equivocally th e absolute con figuration in cycloadducts 11
an d 12, we tried to obtain a crystallin e derivative suitable for X-ray diffrac-
tion an alysis. Hydrogen ation of com poun d 11c an d subsequen t deacetyl-
ation of 13 afforded crystallin e tetrah ydropyran derivative 14 (Sch em e 4)
th e X-ray an alysis of wh ich (Fig. 1) con firm ed th e 2R,4S,6S-con figuration at
th e ch iral carbon atom s of th e tetrah ydropyran rin g. From th is it follows
TABLE I
Selectivity of cycloaddition s with ch iral vin yl eth ers
Startin g oxadien e Ch iral vin yl eth er
Reaction tim e, days Ratio of cycloadducts 11:12
1a
1b
1c
1d
1e
1a
1b
1c
1d
1e
9
9
9
4
6
5
2
9
4
6
5
2
98:2
95:5
95:5
94:6
95:5
5:95
6:94
2:98
4:96
5:95
9
9
9
10
10
10
10
10
Collect. Czech. Chem. Commun. (Vol. 70) (2005)

1418
Štěpánek et al.:
th at cycloadduct 11c m ust h ave th e 2R,4R-con figuration at th e ch iral
carbon atom s of th e 3,4-dih ydro-2H-pyran rin g. Th is result con firm s
th at cycloaddition reaction of oxadien es 1a–1e with th e vin yl eth er 9 of
S-con figuration leads to th e cycloadducts 11a–11e with 2R,4R-con figura-
tion of th e 3,4-dih ydro-2H-pyran rin g, wh ereas th e reaction with th e vin yl
eth er 10 of R-con figuration affords th e cycloadducts 12a–12e of th e oppo-
site con figuration , i.e. 2S,4S.
RO OR
RO
AcO OAc
6'
5'
4'
O
O
2'
AcO
3'
1'
N
N
RO
AcO
5
4
S
6
1''
S
S
S
R
(i)
R
O
R O
3
2
S
S
O
COOCH3
O
COOCH3
Ph
Ph
(i) H2, 10% Pd(C), methanol; (ii) KCN/methanol
13: R = Ac
14: R = H
(ii)
SCHEME 4
FIG. 1
ORTEP drawin g of 14 (30% probability ellipsoids). Th e h ydrogen atom s (except rin g h ydro-
gen s) an d m olecule of m eth an ol are om itted for clarity
Collect. Czech. Chem. Commun. (Vol. 70) (2005)

Precursors of α-C-(1→3)-Disaccharides
1419
In con clusion , th e ch iral vin yl eth ers 9 an d 10, prepared from both en an -
tiom ers of m an delic acid, en able a h igh ly diastereoselective preparation
of cycloadducts 11 or 12, wh ich are direct precursors of α-C-(1→3)-
disacch arides. Th e con figuration of th e m on osacch aride m oiety an d th e
protectin g groups in th e startin g oxadien e 1 h as n o effect on th e
stereoselectivity of th e reaction . X-ray an alysis of com poun d 14 con firm ed
th at th e reaction of th e ch iral vin yl eth er 9 of S-con figuration leads to
precursors 11a–11e, con vertible in to α-C-(1→3)-disacch arides in wh ich th e
2-deoxy-arabino-h exopyran ose m oiety h as D-con figuration (as in com -
poun d 4). On th e oth er h an d, th e use of ch iral vin yl eth er 10 of R-con figu-
ration leads to precursors 12a–12e th at on furth er tran sform ation can af-
ford α-C-(1→3)-disacch arides with L-con figuration of th e 2-deoxy-arabino-
h exopyran ose m oiety (like in com poun d 5).
EXPERIMENTAL
Th e syn th esis of oxadien es 1a an d 1b was described in our previous paper2. Ch iral en ol
eth ers 10 an d 11 were syn th esized accordin g to th e procedure described in ref.6
Th e m eltin g poin ts are n ot corrected. TLC was perform ed on HF254 plates (Merck), detec-
tion with UV ligh t or by sprayin g with a solution of 5 g of Ce(SO4)2·4H2O in 500 m l 10%
H2SO4 an d subsequen t h eatin g. Flash colum n ch rom atograph y was perform ed on silica gel
(Merck, 100–160 µm ) in solven ts distilled prior to use. Specific optical rotation s were m ea-
sured at 25 °C on a Jasco DIP-370 spectropolarim eter an d are given in 10–1 deg cm 2 g–1 1H
.
an d 13C NMR spectra were taken on a Bruker DRX 500 Avan ce spectrom eter at 500.132 MHz
(1H NMR) an d at 125.767 MHz (13C NMR) usin g tetram eth ylsilan e as in tern al stan dard.
Ch em ical sh ifts in 1H an d 13C NMR spectra are given in ppm (δ), couplin g con stan ts J in Hz.
1H an d 13C NMR sign al assign m en ts were con firm ed by 2D COSY an d HMQC wh en n eces-
sary. NOE con n ectivities were obtain ed usin g 1D 1H DPFGSE-NOE experim en t. Mass spectra
were taken on a Q TOF m icrom ass spectrom eter with direct in let (ESI) or on a ZAB-EQ
(VG An alytical) in strum en t (FAB) with Xe ion ization , acceleratin g voltage 8 kV. HPLC was
perform ed usin g an Agilen t 1100 in strum en t equipped with gradien t pum p, colum n th erm o-
stat an d UV detector, on a 250 × 4.6 m m colum n packed with 5 µm Supelco BDS Hypersil
C-18, m obile ph ase m eth an ol–water.
1-(α-D-Galactopyran osyl)prop-2-en e (6)
Allyltrim eth ylsilan e (16.3 m l, 11.67 g, 102 m m ol) an d BF3·Et2O (13.2 m l, 14.78 g, 104 m m ol)
were added to a solution of pen ta-O-acetyl-D-galactose (10 g, 25.64 m m ol) in dry aceton itrile
(160 m l). Th e reaction m ixture was refluxed un der argon for 4 h , cooled, poured in to satu-
rated solution of NaHCO3 (400 m l) an d extracted with dich lorom eth an e (3 × 100 m l). Th e
organ ic ph ase was wash ed with water (3×), dried, th e solven t was evaporated an d th e resi-
due subjected to ch rom atograph y on silica gel (petroleum eth er–eth yl acetate 4:1). Yield 9.1 g
(97%) of 1-(tetra-O-acetyl-D-galactopyran osyl)prop-2-en e as 6:1 m ixture of α- an d β-epim ers
(accordin g to 1H NMR). Th is m ixture was dissolved in 200 m l of 0.1 M MeONa in MeOH an d
after stirrin g for 2 h it was n eutralized by addition of Dowex, suspen ded in m eth an ol. Th e
Collect. Czech. Chem. Commun. (Vol. 70) (2005)

1420
Štěpánek et al.:
ion exch an ger was rem oved by filtration an d th e solven t was evaporated. Th e residue (4.97 g)
was dissolved in eth an ol (10 m l), an d eth er was slowly added to persisten t turbidity. After
12 h th e solution deposited 3.1 g of th e title com poun d, m .p. 134–135 °C. [α]D +113.1 (c 1.0,
H2O). 1H NMR (D2O) (for n um berin g of atom s see Sch em e 2): 2.31 ddd, 1 H, J(1a,1b) = 14.9,
J(1a,2) = 6.1, J(1a,1′) = 4.5 (H-1a); 2.44 ddd, 1 H, J(1a,1b) = 14.9, J(1b,2) = 7.9, J(1b,1′) = 11.8
(H-1b); 3.63 d, 2 H, J(6′ab,5′) = 6.1 (H-6′a, H-6′b); 3.73–3.77 m , 2 H (H-3′,H-5′); 3.91 dd, 1 H,
J(3′,4′) = 3.9, J(4′,5′) = 3.9 (H-4′); 3.93 dd, 1 H, J(2′,3′) =10.1, J(1′,2′) = 6.1 (H-2′); 4.04 ddd, 1 H,
J(1a,1′) = 4.5, J(1b,1′) = 11.8, J(1′,2′) = 6.1 (H-1′); 5.07 d, 1 H, J(2,3cis) = 10.2 (H-3cis); 5.13 d,
1 H, J(2,3trans) = 17.1 (H-3trans); 5.79 dddd, 1 H, J(1a,2) = 6.1, J(1b,2) = 7.9, J(2,3cis) = 10.2,
J(2,3trans) = 17.1 (H-2). 13C NMR (D2O): 29.91 (C-1); 62.03 (C-6′); 69.37 (C-2′); 70.12 (C-4′);
70.81 (C-3′); 72.80 (C-5′); 76.04 (C-1′); 118.45 (C-3); 136.11 (C-2). For 6 (C9H16O5) calcu-
lated: relative m olecular m ass 204.22, m on oisotopic m ass 204.09. MS (FAB), m/z: 205.1 [M +
H]+. For C9H16O5 (204.2) calculated: 52.93% C, 7.90% H; foun d: 52.95% C, 7.98% H.
1-(Tetra-O-acetyl-α-D-galactopyran osyl)prop-2-en e (7)
Com poun d 6 (5.8 g, 28.4 m m ol) was added to a m ixture of pyridin e (40 m l) an d Ac2O
(20 m l) an d th e form ed suspen sion was stirred at room tem perature to dissolution (18 h ).
Th e reaction m ixture was th en poured on to ice (200 g) an d extracted with dich lorom eth an e
(3 × 100 m l). Th e organ ic ph ase was wash ed with satureted solution of Na2CO3, water, an d
dried. Evaporation of th e solven t afforded 10.1 g (95%) of product 7, iden tical with th e
kn own com poun d8.
1-(Tetra-O-ben zyl-α-D-galactopyran osyl)prop-2-en e (8)
A suspen sion of NaH in m in eral oil (60%; 6.8 g, 170 m m ol) was added to a solution of com -
poun d 6 (5.8 g, 28.4 m m ol) an d tetrabutylam m on ium iodide (0.6 g) in DMF (80 m l) an d
THF (400 m l). After stirrin g at room tem perature for 2 h , ben zyl brom ide (4 × 5 m l) was
added dropwise to th e reaction m ixture in 45 m in in tervals, an d after stirrin g at room tem -
perature for an oth er 3 h th e reaction was quen ch ed by addition of m eth an ol (50 m l). Th e
solven ts were evaporated in vacuo an d th e residue was partition ed between a saturated solu-
tion of NaHCO3 an d dich lorom eth an e. Th e organ ic ph ase was wash ed with water, dried an d
taken down . Subsequen t ch rom atograph y of th e residue on silica gel afforded 15.2 g (95%)
of product 8, RF 0.43 (petroleum eth er–eth yl acetate 10:1), iden tical with th e kn own com -
poun d15
.
(E)-4-(Tetra-O-acetyl-α-D-galactopyran osyl)-1-(th iazol-2-yl)but-2-en -1-on e (1c)
A solution of 1-(tetra-O-acetyl-α-D-galactopyran osyl)prop-2-en e (7) (2.3 g, 6.18 m m ol) in di-
ch lorom eth an e (40 m l) was cooled to –75 °C an d subjected to ozon olysis till th e blue color-
ation persisted. Th e solution was th en decolorized by in troduction of oxygen , an d
2-ph osph oran yliden e-1-(th iazol-2-yl)eth an -1-on e11 (4.1 g, 10.5 m m ol) was im m ediately
added. Th e reaction m ixture was allowed to warm to room tem perature an d stirred for 24 h .
Evaporation of th e solven t in vacuo an d ch rom atograph y afforded 2.18 g (73%) of oily 1c.
RF 0.4 (petroleum eth er–eth yl acetate 2:1). [α]D +73.2 (c 1.0, CHCl3). 1H NMR (CDCl3) (for
n um berin g of atom s see Sch em e 3): 1.99 s, 3 H (CH3CO); 2.05 s, 3 H (CH3CO); 2.11 s, 3 H
(CH3CO); 2.13 s, 3 H (CH3CO); 2.51–2.61 m , 1 H (H-4a); 2.69–2.81 m , 1 H (H-4b); 4.06 dd,
1 H, J(6′a,6′b) = 11.4, J(6′a,5′) = 4.5 (H-6′a); 4.08–4.13 m , 1 H (H-5′); 4.29 dd, 1 H, J(6′a,6′b) =
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Precursors of α-C-(1→3)-Disaccharides
1421
11.4, J(5′,6′b) = 7.9 (H-6′b); 4,47 ddd, 1 H, J(4a,1′) = 9.5, J(4b,1′) = 5.2, J(1′,2′) = 4.8 (H-1′);
5.26 dd, 1 H, J(2′,3′) = 9.0, J(3′,4′) = 2.9 (H-3′); 5.32 dd, 1 H, J(2′,3′) = 9.0, J(1′,2′) = 4.8 (H-2′);
5.54 dd, 1 H, J(3′,4′) = 2.9, J(4′,5′) = 2.7 (H-4′); 7.25 ddd, 1 H, J(2,3) = 15.6, J(3,4a) = 7.0,
J(3,4b) = 3.4 (H-3); 7.41 d, 1 H, J(2,3) = 15.6 (H-2); 7.71 d, 1 H, J = 2.9 (H-th iazole); 8.03 d,
1 H, J = 2.9 (H-th iazole). 13C NMR (CDCl3): 20.43, 20.51, 20.57, 20.61 (CH3CO); 30.21 (C-4);
61.19 (C-6′); 68.05 (C-3′); 68.27 (C-4′); 69.15 (C-5′); 69.75 (C-2′); 70.88 (C-1′); 126.61
(CH-th iazole); 126.79 (C-2); 144.65 (C-3); 144.95 (CH-th iazole); 167.78 (th iazole C-2);
170.57, 169.92, 169.75, 169.42 (CH3CO). For 1c (C21H25NO10S) calculated: relative m olecu-
lar m ass 483.49, m on oisotopic m ass 483.12. MS (ESI), m/z: 484.2 [M + H]+. For C21H25NO10
S
(483.5) calculated: 52.17% C, 5.21% H, 2.90% N; foun d: 51.97% C, 5.32% H, 2.81% N.
(E)-4-(2,3:4,6-Di-O-isopropyliden e-α-D-m an n opyran osyl)-1-(th iazol-2-yl)but-2-en -1-on e (1e)
Th e title com poun d was prepared in th e sam e m an n er as described in th e precedin g experi-
m en t. Reaction of 1-(2,3;4,6-di-O-isopropyliden e-α-D-m an n opyran osyl)prop-2-en e7 (0.2 g,
0.7 m m ol), dich lorom eth an e (5 m l) an d 2-ph osph oran yliden e-1-(th iazol-2-yl)eth an -1-on e11
(0.46 g, 1.19 m m ol) afforded 0.2 g (72%) of oily 1e. RF 0.72 (petroleum eth er–eth yl acetate
2:1). [α]D + 12.0 (c 1.0, CHCl3). 1H NMR (C6D6–CD3OD 9:1): 1.16 s, 3 H ((CH3)2C); 1.23 s,
3 H ((CH3)2C); 1.41 s, 3 H ((CH3)2C); 1.42 s, 3 H ((CH3)2C); 2.25–2.18 m , 2 H (H-4a, H-4b);
3.26 ddd, 1 H, J(4′,5′) = 10.5, J(5′,6′a) = 10.3, J(5′,6′b) = 5.5 (H-5′); 3.55 dd, 1 H, J(6′a,6′b) =
10.8, J(5′,6′a) = 10.3 (H-6′a); 3.71–3.67 m , 1 H (H-2′); 3.78 dd, 1 H, J(6′a,6′b) = 10.8, J(5′,6′b) =
5.5 (H-6′b); 3.88 ddd, 1 H, J(4a,1′) = 12.9, J(4b,1′) = 6.8, J(1′,2′) = 6.0 (H-1′); 3.98 dd, 1 H,
J(3′,4′) = 7.3, J(4′,5′) = 10.5 (H-4′); 4.06 dd, 1 H, J(3′,4′) = 7.3, J(3′,2′) = 7.0 (H-3′); 6.76 d, 1 H,
J = 2.7 (H-th iazole); 7.38 ddd, 1 H, J(2,3) = 15.6, J(3,4a) = 7.5, J(3,4b) = 7.5 (H-3); 7.50 d, 1 H,
J(2,3) = 15.6 (H-2); 7.56 d, 1 H, J = 2.7 (H-th iazole). 13C NMR (C6D6–CD3OD 9:1): 18.72,
25.31, 27.67, 29.19 (4 × (CH3)2C); 35.48 (C-4); 62.17 (C-6′); 64.59 (C-5′); 72.77 (C-4′); 72.87
(C-1′); 75.56 (C-3′); 75.96 (C-2′); 99.51 ((CH3)2C); 109.65 ((CH3)2C); 127.09 (CH-th iazole);
127.52 (C-3); 144.76 (CH-th iazole); 146.39 (C-2); 168.53 (th iazole C-2); 181.48 (C-1). For
1e (C19H25NO6S) calculated: relative m olecular m ass 395.47, m on oisotopic m ass 395.14.
MS (FAB), m/z: 396.1 [M + H]+. For C19H25NO6S (395.5), calculated: 57.70% C, 6.37% H,
3.54% N; foun d: 57.52% C, 6.48% H, 3.44% N.
(E)-4-(Tetra-O-ben zyl-α-D-galactopyran osyl)-1-(th iazol-2-yl)but-2-en -1-on e (1d )
A solution of propen e 8 (10 g, 17.7 m m ol) in dich lorom eth an e (85 m l) an d m eth an ol (15 m l)
was cooled to –75 °C an d ozon ized to persisten t blue coloration . Th en , at th e sam e tem pera-
ture, th e solution was decolorized by in troducin g oxygen . Dim eth yl sulfide (12.9 m l, 10.9 g,
176 m m ol) an d solid NaHCO3 (2.5 g, 29.7 m m ol) were added an d th e reaction m ixture was
stirred at room tem perature for 24 h an d th en filtered. Th e solven ts were evaporated in
vacuo an d ch rom atograph y of th e residue on silica gel afforded 2-(tetra-O-ben zyl-α-D-galacto-
pyran osyl)eth an al (9.7 g, 89%). RF 0.35 (petroleum eth er–eth yl acetate 5:1), iden tical with
th e auth en tic com poun d16. To a solution of th e aldeh yde (5 g, 8.82 m m ol) in ch loroform
(25 m l) was added 2-ph osph oran yliden e-1-(th iazol-2-yl)eth an -1-on e11 (6.85 g, 17.64 m m ol)
an d th e reaction m ixture was stirred at 60 °C for 96 h . Evaporation of th e solven t in vacuo
an d ch rom atograph y on silica gel gave 4.8 g (81%) of oily oxadien e 1d . RF 0.8 (petroleum
eth er–eth yl acetate 5:1). [α]D +48.3 (c 1.0, CHCl3). 1H NMR (CHCl3): 2.59–2.80 m , 2 H (H-4a,
H-4b); 3.70 dd, 1 H, J(6′a,6′b) = 10.6, J(5′,6′a) = 4.7 (H-6′a); 3.87 dd, 1 H, J(6′a,6′b) = 10.6,
J(5′,6′b) = 7.3 (H-6′b); 3.74–4.13 m , 4 H (H-2′, H-3′, H-4′, H-5′); 4.15–4.24 m , 1 H (H-1′);
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Štěpánek et al.:
4.44–4.80 m , 8 H (4 × C6H5-CH2); 7.21–7.41 m , 22 H (4 × C6H5, H-2, H-3); 7.65 d, 1 H, J =
2.9 (H-th iazole); 7.99 d, 1 H, J = 2.9 (H-th iazole). 13C NMR (CHCl3): 31.95 (C-4); 67.39
(C-6′); 70.61 (C-1′); 73.05, 74.32, 76.58 (C-2′, C-3′, C-4′, C-5′, on e of th em overlapped by
C6H5-CH2); 73.47, 76.92, 77.35, 77.76 (4 × C6H5-CH2); 126.55 (CH-th iazole); 127.68–128.70
(20 × C6H5, C-3); 138.23, 138.58, 138.66, 138.67 (4 × ipso C6H5); 144.93 (CH-th iazole);
148.02 (C-2); 168.51 (th iazole C-2); 181.57 (C-1). For 1d (C41H41NO6S) calculated: relative
m olecular m ass 675.84, m on oisotopic m ass 675.27. MS (ESI), m/z: 676.4 [M + H]+. For
C
41H41NO6S (675.8) calculated: 72.86% C, 6.11% H, 2.07% N; foun d: 72.96% C, 6.31% H,
1.95% N.
Cycloaddition of Oxadien es 1a–1e with Ch iral En ol Eth er 9 or 10. Gen eral Procedure
Eu(fod)3 was added to a solution of th e correspon din g oxadien e 1 an d vin yl eth er 9 or 10 in
dry dich lorom eth an e an d th e reaction m ixture was stirred at room tem perature un der argon .
Th e reaction was m on itored by TLC an d after disappearan ce of th e startin g oxadien e it was
an alyzed by HPLC. Th e reaction tim es an d cycloadduct ratios for th e products are given in
Table I. After evaporation of th e solven t in vacuo, th e product was isolated by ch rom atogra-
ph y on silica gel. In th is m an n er, th e followin g com poun ds 11 an d 12 were prepared.
Methyl (S)-2-phenyl-2-({(2R,4R)-4-[(tetra-O-acetyl-α-D-glucopyranosyl)methyl]-6-(thiazol-2-yl)-
3,4-dihydro-2H-pyran-2-yl}oxy)acetate (11a). Reaction of oxadien e 1a (128 m g, 0.27 m m ol),
vin yl eth er 9 (89 m g, 0.46 m m ol) an d Eu(fod)3 (25 m g, 0.026 m m ol) afforded 140 m g (78%)
of com poun d 11a. RF 0.59 (petroleum eth er–dieth yl eth er–dich lorom eth an e 1:1:4). [α]D
+63.6 (c 1.0, CHCl3). 1H NMR (CDCl3) (for n um berin g of atom s see Sch em e 4): 1.77–1.84 m ,
1 H (H-1′′a); 1.88 s, 3 H (CH3CO); 1.97–2.12 m , 19 H (3 × CH3CO); 2.12–2.19 m , 1 H
(H-1′′b); 2.22–2.32 m ,
2 H (H-3eq, H-3ax); 2.53–2.58 m , 1 H (H-4); 3.74 s, 3 H
(CH-COOCH3); 4.04–4.09 m , 1 H (H-5′); 4.15 dd, 1 H, J(5′,6′a) = 2.0, J(6′a,6′b) = 12.3 (H-6′a);
4.28 dd, 1 H, J(5′,6′a) = 4.9, J(6′a,6′b) = 12.3 (H-6′b); 4.31–4.39 m , 1 H (H-1′); 5.03 dd, 1 H,
J(3′,4′) = 9.1, J(4′,5′) = 9.3 (H-4′); 5.07 dd, 1 H, J(1′,2′) = 5.8, J(2′,3′) = 9.6 (H-2′); 5.25 dd, 1 H,
J(2′,3′) = 9.2, J(3′,4′) = 9.3 (H-3′); 5.44 s, 1 H (CH-COOCH3); 5.51 dd, 1 H, J(2,3ax) = 5.9,
J(2,3eq) = 3.1 (H-2); 6.04 d, 1 H, J(4, 5) = 4.3 (H-5); 7.24–7.39 m , 6 H (C6H5, H-th iazole);
7.76 d, 1 H, J = 3.1 (H-th iazole). 13C NMR (CDCl3): 20.52 (CH3CO); 26.63 (C-4); 30.09
(C-1′′); 31.33 (C-3); 52.24 (CH-COOCH3); 61.18 (C-6′); 68.54 (C-5′); 68.67 (C-4′); 69.91
(C-2′); 70.33 (C-3′); 71.98 (C-1′); 77.67 (CH-COOCH3); 97.18 (C-2); 103.92 (C-5); 118.59
(CH-th iazole); 127.03–128.53 (5
× C6H5); 135.99 (ipso C6H5); 142.97 (C-6); 143.18
(CH-th iazole); 163.67 (th iazole C-2); 2 × 169.37, 169.89, 170.58, 170.68 (4 × CH3CO,
CH-COOCH3). For 11a (C32H37NO13S) calculated: relative m olecular m ass 675.71, m on oiso-
topic m ass 675.19. MS (FAB), m/z: 676.2 [M + H]+, 698.3 [M + Na]+. For C32H37NO13S (675.7)
calculated: 56.88% C, 5.52% H, 2.07% N; foun d: 56.74% C, 5.63% H, 1.95% N.
Methyl (S)-2-phenyl-2-({(2R,4R)-4-[(tetra-O-benzyl-α-D-glucopyranosyl)methyl]-6-(thiazol-2-yl)-
3,4-dihydro-2H-pyran-2-yl}oxy)acetate (11b). Reaction of oxadien e 1b (1.45 g, 2.14 m m ol),
vin yl eth er 9 (700 m g, 3.64 m m ol) an d Eu(fod)3 (230 m g, 0.22 m m ol) afforded 1.48 g (80%)
of com poun d 11b. RF 0.18 (petroleum eth er–eth yl acetate 6:1). [α]D +61.3 (c 0.2, CHCl3).
1H NMR (CDCl3): 1.93–1.99 m , 1 H (H-1′′a); 2.05–2.14 m , 1 H (H-1′′b); 2.16–2.23 m , 1 H
(H-3ax); 2.26–2.32 m , 1 H (H-3eq); 2.56–2.65 m , 1 H (H-4); 3.63–3.82 m , 9 H (H-2′, H-3′,
H-4′, H-5′, H-6′a, H-6′b, CH-COOCH3); 4.16–4.23 m , 1 H (H-1′); 4.51–4. 96 m , 8 H (4 ×
C6H5-CH2); 5.49 dd, 1 H, J(2,3eq) = 2.5, J(2,3ax) = 4.5 (H-2); 5.51 s, 1 H (CH-COOCH3);
6.09 d, 1 H, J(4,5) = 3.9 (H-5); 7.19–7.46 m , 26 H (5 × C6H5, H-th iazole); 7.82 d, 1 H, J = 3.2
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Precursors of α-C-(1→3)-Disaccharides
1423
(H-th iazole). 13C NMR (CDCl3): 27.21 (C-4); 30.82 (C-1′′); 32.22 (C-3); 52.29 (CH-COOCH3);
68.99 (C-6′); 72.98 (C-1′); 73.02, 73.48, 74.88, 75.39 (4 × C6H5-CH2); 71.31, 77.25, 77.99,
79.98, 82.33 (C-2′, C-3′, C-4′, C-5′, CH-COOCH3); 97.81 (C-2); 105.02 (C-5); 118.56
(CH-th iazole); 128.50–127.27 (25 × C6H5); 136.06–138.72 (5 × ipso C6H5); 142.95 (C-6);
143.22 (CH-th iazole); 164.14 (th iazole C-2); 170.98 (CH-COOCH3). For 11b (C52H53NO9S)
calculated: relative m olecular m ass 868.06, m on oisotopic m ass 867.34. MS (FAB), m/z: 868.3
[M + H]+. For C52H53NO9S (868.1) calculated: 71.95% C, 6.15% H, 1.61% N; foun d: 72.36% C,
6.11% H, 1.67% N.
Methyl (S)-2-phenyl-2-({(2R,4R)-4-[(tetra-O-acetyl-α-D-galactopyranosyl)methyl]-6-(thiazol-2-yl)-
3,4-dihydro-2H-pyran-2-yl}oxy)acetate (11c). Reaction of oxadien e 1c (500 m g, 1.03 m m ol),
vin yl eth er 9 (332 m g, 1.75 m m ol) an d Eu(fod)3 (107 m g, 0.1 m m ol) afforded 546 m g (78%)
of com poun d 11c. RF 0.59 (petroleum eth er–dieth yl eth er–dich lorom eth an e 1:1:4). [α]D
+71.2 (c 0.3, CHCl3). 1H NMR (CDCl3): 1.63–1.76 m , 2 H (H-1′′a, H-1′′b); 1.96–2.15 m , 13 H,
(4 × CH3CO, H-3ax); 2.29 ddd, 1 H, J(3eq,3ax) = 13.5, J(3eq,4) = 7.1, J(2,3eq) = 1.9 (H-3eq);
2.62 m , 1 H (H-4); 3.76 s, 3 H (CH-COOCH3); 3.90–3.95 m , 1 H (H-5′); 4.08 dd, 1 H,
J(6′a,6′b) = 11.5, J(5′,6′a) = 5,5 (H-6′a); 4.22 dd, 1 H, J(6′a,6′b) = 11.5, J(5′,6′b) = 7.7 (H-6′b);
4.37–4.43 m , 1 H (H-1′); 5.14 dd, 1 H, J(2′,3′) = 9.2, J(3′,4′) = 3.2 (H-3′); 5.27 dd, 1 H, J(2′,3′) =
9.2, J(1′,2′) = 5.1 (H-2′); 5.32–5.36 m , 1 H (H-4′); 5.47 s, 1 H (CH-COOCH3); 5.49–5.52 m ,
1 H (H-2); 6.05 d, 1 H, J(4,5) = 3.8 (H-5); 7.27–7. 44 m , 6 H (C6H5, H-th iazole); 7.77 d, 1 H,
J = 2.9 (H-th iazole). 13C NMR (CDCl3): 20.69 (CH3CO); 26.81 (C-4); 31.19 (C-1′′); 31.33
(C-3); 52.38 (CH-COOCH3); 61.18 (C-6′); 67.47 (C-4′); 67.87 (C-3′); 68.22 (C-5′); 68.31 (C-2′);
70.29 (C-1′); 77.57 (CH-COOCH3); 97.68 (C-2); 105.39 (C-5); 118.59 (CH-th iazole);
128.64–127.14 (5 × C6H5); 136.09 (ipso C6H5); 143.09 (C-6); 143.34 (CH-th iazole); 163.77
(th iazole C-2); 2 × 169.77, 170.05, 170.47, 170.84 (4 × CH3CO, CH-COOCH3). For 11c
(C32H37NO13S) calculated: relative m olecular m ass 675.71, m on oisotopic m ass 675.19. MS
(FAB), m/z: 676.2 [M + H]+, 698.3 [M + Na]+. For C32H37NO13S (675.7) calculated: 56.88% C,
5.52% H, 2.07% N; foun d: 56.93% C, 5.81% H, 1.83% N.
Methyl (S)-2-phenyl-2-({(2R,4R)-4-[(tetra-O-benzyl-α-D-galactopyranosyl)methyl]-6-(thiazol-2-yl)-
3,4-dihydro-2H-pyran-2-yl}oxy)acetate (11d ). Reaction of oxadien e 1d (2.12 g, 3.14 m m ol),
vin yl eth er 9 (1 g, 5.34 m m ol) an d Eu(fod)3 (0.33 g, 0.31 m m ol) afforded 2.25 g (83%) of
com poun d 11d . RF 0.30 (petroleum eth er–eth yl acetate 3:1). [α]D +53.7 (c 0.14, CHCl3).
1H NMR (CDCl3): 1.64–1.78 m , 1 H (H-1′′a); 1.90–2.06 m , 2 H (H-1′′b, H-3ax); 2.30 ddd, 1 H,
J(3eq,3ax) = 13.8, J(3eq,4) = 6.7, J(2,3eq) = 2.4 (H-3eq); 2.48–2. 65 m , 1 H (H-4); 3.63–3.82 m ,
9 H (H-2′, H-3′, H-4′, H-5′, H-6′a, H-6′b, CH-COOCH3); 4.02–4. 21 m , 1 H (H-1′); 4.45–4.79 m ,
8 H (4 × C6H5-CH2); 5.41 dd, 1 H, J(2,3ax) = 5.6, J(2,3eq) = 2.4 (H-2); 5.49 s, 1 H
(CH-COOCH3); 6.04 d, 1 H, J(4,5) = 3.5 (H-5); 7.18–7. 51 m , 26 H (5 × C6H5, CH-th iazole);
7.78 d, 1 H, J = 3.2 (H-th iazole). 13C NMR (CDCl3): 27.58 (C-4); 33.48 (C-1′′); 33.54 (C-3);
52.63 (CH-COOCH3); 67.86 (C-6′); 72.53 (C-1′); 73.24, 73.44, 73.59, 73.63 (4 × C6H5-CH2);
74.62, 77.25, 77.32, 77.42, 77.75 (C-2′, C-3′, C-4′, C-5′, CH-COOCH3); 97.56 (C-2); 105.19
(C-5); 118.82 (CH-th iazole); 127.98–128.85 (25 × C6H5); 136.45, 138.51, 138.71, 138.79,
138.84 (5 × ipso C6H5); 143.41 (C-6); 143.49 (CH-th iazole); 164.44 (C-2 th iazole); 171.24
(CH-COOCH3). For 11d (C52H53NO9S) calculated: relative m olecular m ass 868.06,
m on oisotopic m ass 867.34. MS (FAB), m/z: 868.3 [M + H]+. For C52H53NO9S (868.1) calcu-
lated: 71.95% C, 6.15% H, 1.61% N; foun d: 72.23% C, 6.11% H, 1.48% N.
Methyl (S)-2-phenyl-2-({(2R,4R)-4-[(2,3:4,6-di-O-isopropylidene-α-D-mannopyranosyl)methyl]-
6-(thiazol-2-yl)-3,4-dihydro-2H-pyran-2-yl}oxy)acetate (11e). Reaction of oxadien e 1e (490 m g,
1.24 m m ol), vin yl eth er 9 (405 m g, 2.11 m m ol) an d Eu(fod)3 (130 m g, 0.124 m m ol) af-
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Štěpánek et al.:
forded 590 m g (83%) of com poun d 11e. RF 0.4 (petroleum eth er–eth yl acetate 2:1). [α]D
+59.6 (c 0.2, CHCl3). 1H NMR (CDCl3): 1.32 s, 3 H ((CH3)2C); 1.44 s, 3 H ((CH3)2C); 1.49 s,
3 H ((CH3)2C); 1.55 s, 3 H ((CH3)2C); 1.82–1.95 m , 2 H (H-1′′a, H-1′′b); 2.01–2.09 m 1 H
(H-3ax); 2.25–2.32 m , 1 H (H-3eq); 2.65–2.74 m , 1 H (H-4); 3.37–3.44 m , 1 H (H-6′a);
3.72–3.79 m , 4 H (H-5′, CH-COOCH3); 3.89–3.98 m , 3 H (H-6′b, H-3′, H-2′); 4.10 dd, 1 H, J =
7.6, J = 7.2 (H-4′); 4.16–4.22 m , 1 H (H-1′); 5.48–5.51 m , 2 H (H-2, CH-COOCH3); 6.07 d,
1 H, J(4,5) = 3.1 (H-5); 7.27–7.51 m , 6 H (5 × C6H5, H-th iazole); 7.77 d, 1 H (H-th iazole).
13C NMR (CDCl3): 18.92 (C-4); 25.49, 26.47, 27.79, 29.06 (4 × (CH3)2C); 32.65 (C-1′); 37.19
(C-3); 52.39 (CH-COOCH3); 62.73 (C-6′); 62.58 (C-3′); 71.87 (C-2′); 72.62 (C-4′); 75.18 (C-5′);
75.26 (C-1′); 77.62 (CH-COOCH3); 97.79 (C-2); 99.56 (CH3)2C); 103.86 (C-5); 109.34
(CH3)2C); 118.63 (CH-th iazole); 127.25, 128.48, 128.64, 128.76, 128.96 (5 × C6H5); 136.06
(ipso C6H5); 143.25 (CH-th iazole); 143.35 (C-6); 169.95 (C-2 th iazole); 170.94 (CH-COOCH3).
For 11e (C30H37NO9S) calculated: relative m olecular m ass 587.69, m on oisotopic m ass 587.22.
MS (ESI), m/z: 610.4 [M + Na]+. For C30H37NO9S (587.7) calculated: 61.31% C, 6.35% H,
2.38% N; foun d: 61.58% C, 6.11% H, 2.07% N.
Methyl (R)-2-phenyl-2-({(2S,4S)-4-[(tetra-O-acetyl-α-D-glucopyranosyl)methyl]-6-(thiazol-2-yl)-
3,4-dihydro-2H-pyran-2-yl}oxy)acetate (12a). Reaction of oxadien e 1a (130 m g, 0.27 m m ol),
vin yl eth er 10 (89 m g, 0.46 m m ol) an d Eu(fod)3 (25 m g, 0.026 m m ol) afforded 137 m g
(75%) of com poun d 12a. RF 0.59 (petroleum eth er–dieth yl eth er–dich lorom eth an e 1:1:4).
[α]D +15.9 (c 1.0, CHCl3). 1H NMR (CDCl3): 1.71–1.79 m , 1 H (H-1′′a); 1.93–2.09 m , 13 H
(4 × CH3CO, H-3ax); 2.12–2.22 m , 1 H (H-1′′b); 2.24–2.32 m , 1 H (H-3eq); 2.54–2.63 m , 1 H
(H-4); 3.67–3.78 m , 4 H (CH-COOCH3, H-5′); 3.93–3.07 m , 1 H (H-6′a); 4.20 dd, 1 H,
J(6a′,6b′) = 12.3, J(5′,6′b) = 4.7 (H-6′b); 4.31–4.39 m , 1 H (H-1′); 4.98 dd, 1 H, J(3′,4′) = 9.0,
J(4′,5′) = 8.9 (H-4′); 5.06 dd, 1 H, J(1′,2′) = 5.7, J(2′,3′) = 9.2 (H-2′); 5.22 dd, 1 H, J(2′,3′) = 9.0,
J(3′,4′) = 9.0 (H-3′); 5.44 s, 1 H (CH-COOCH3); 5.46–5.52 m , 1 H (H-2); 6.07 d, 1 H, J(4,5) =
3.8 (H-5); 7.23–7.41 m , 6 H (C6H5, H-th iazole); 7.74 d, 1 H, J = 2.9 (H-th iazole). 13C NMR
(CDCl3): 20.51 (CH3CO); 26.50 (C-4); 30.62 (C-1′′); 31.14 (C-3); 52.26 (CH-COOCH3); 61.82
(C-6′); 68.36 (C-4′); 68.83 (C-5′); 69.97 (C-2′); 70.18 (C-3′); 71.09 (C-1′); 77.58
(CH-COOCH3); 97.45 (C-2); 105.06 (C-5); 118.52 (CH-th iazole); 126.92–128.51 (5 × C6H5);
135.99 (ipso C6H5); 142.99 (C-6); 143.24 (CH-th iazole); 163.55 (th iazole C-2); 169.32,
169.48, 169.81, 170.52, 170.69 (4 × CH3CO, CH-COOCH3). For 12a (C32H37NO13S) calcu-
lated: relative m olecular m ass 675.71, m on oisotopic m ass 675.19. MS (FAB), m/z: 676.2 [M +
H]+, 698.3 [M + Na]+. For C32H37NO13S (675.7) calculated: 56.88% C, 5.52% H, 2.07% N;
foun d: 56.93% C, 5.43% H, 1.96% N.
Methyl (R)-2-phenyl-2-({(2S,4S)-4-[(tetra-O-benzyl-α-D-glucopyranosyl)methyl]-6-(thiazol-2-yl)-
3,4-dihydro-2H-pyran-2-yl}oxy)acetate (12b). Reaction of oxadien e 1b (150 m g, 0.22 m m ol),
vin yl eth er 10 (73 m g, 0.38 m m ol) an d Eu(fod)3 (24 m g, 0.023 m m ol) afforded 150 m g
(78%) of com poun d 12b. RF 0.19 (petroleum eth er–eth yl acetate 6:1). [α]D +19.0 (c 0.079,
CHCl3). 1H NMR (CDCl3): 1.83–1.97 m , 2 H (H-1′′a, H-3ax); 2.02–2.13 m , 1 H (H-1′′b);
2.28–2.36 m , 1 H (H-3eq); 2.56–2.66 m , 1 H (H-4); 3.47–3.80 m , 9 H (H-2′, H-3′, H-4′, H-5′,
H-6′a, H-6′b, CH-COOCH3); 4.15–4.23 m , 1 H (H-1′); 4.42–4. 93 m , 8 H (4 × C6H5-CH2);
5.41–5.47 m , 1 H (H-2); 5.50 s, 1 H (CH-COOCH3); 6.01 d, 1 H, J(4,5) = 3.5 (H-5); 7.09–7.46
m , 26 H (5 × C6H5, H-th iazol); 7.74 d, 1 H, J = 3.1 (H-th iazol). 13C NMR (CDCl3): 27.05
(C-4); 30.17 (C-1′′); 31.82 (C-3); 52.37 (CH-COOCH3); 68.79 (C-6′); 71.35 (C-3′); 72.11 (C-1′);
72.93, 73.47, 74.91, 75.42 (4 × C6H5-CH2); 77.79, 77.95, 77.99, 79.68, 82.31 (C-2′, C-4′, C-5′,
CH-COOCH3); 98.34 (C-2); 106.92 (C-5); 118.50 (CH-th iazol); 128.58–128.56 (25 × C6H5);
136.06–138.72 (5 × ipso C6H5); 142.86 (CH-th iazol); 142.88 (C-6); 164.02 (th iazol C-2);
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Precursors of α-C-(1→3)-Disaccharides
1425
170.95 (CH-COOCH3). For 12b (C52H53NO9S) calculated: relative m olecular m ass 868.06,
m on oisotopic m ass 867.34. MS (FAB), m/z: 868.3 [M + H]+. For C52H53NO9S (868.1) calcu-
lated: 71.95% C, 6.15% H, 1.61% N; foun d: 72.13% C, 6.04% H, 1.43% N.
Methyl (R)-2-phenyl-2-({(2S,4S)-4-[(tetra-O-acetyl-α-D-galactopyranosyl)methyl]-6-(thiazol-2-yl)-
3,4-dihydro-2H-pyran-2-yl}oxy)acetate (12c). Reaction of oxadien e 1c (500 m g, 1.03 m m ol),
vin yl eth er 10 (337 m g, 1.75 m m ol) an d Eu(fod)3 (107 m g, 0.103 m m ol) afforded 470 m g
(71%) of com poun d 12c. RF 0.51 (petroleum eth er–dieth yl eth er–dich lorom eth an e 1:1:4).
[α]D +22.2 (c 0.2, CHCl3). 1H NMR (CDCl3): 1.73–1.86 m , 2 H (H-1′′a, H-1′′b); 1.90–2.20 m ,
13 H (4 × CH3CO, H-3ax); 2.27–2.35 m , 1 H (H-3eq); 2.56–2.63 m , 1 H (H-4); 3.75 s, 3 H
(CH-COOCH3); 4.09–4.29 m , 3 H (H-5′, H-6′a, H-6′b); 4.36–4.44 m , 1 H (H-1′); 5.14 dd, 1 H,
J(2′,3′) = 9.4, J(3′,4′) = 2.9 (H-3′); 5.27 dd, 1 H, J(2′,3′) = 9.4, J(1′,2′) = 5.3 (H-2′); 5.40–5.45 m ,
2 H (CH-COOCH3, H-5′); 5.50–5.56 m , 1 H (H-2); 6.05 d, 1 H, J(4,5) = 3.7 (H-5); 7.26–7.39 m ,
6 H (C6H5, H-th iazole); 7.77 d, 1 H, J = 2.5 (H-th iazole). 13C NMR (CDCl3): 20.71 (4 ×
CH3CO); 26.86 (C-4); 30.88 (C-1′′); 31.93 (C-3); 52.35 (CH-COOCH3); 62.71 (C-6′);
67.94–68.01 (C-2′, C-3′, C-4′, C-5′); 71.34 (C-1′); 77.89 (CH-COOCH3); 97.57 (C-2); 104.01
(C-5); 118.68 (CH-th iazole); 127.15, 127.23, 128.60, 128.66, 128.85 (5 × C6H5); 136.07 (ipso
C6H5); 143.25 (CH-th iazole); 143.14 (C-6); 163.85 (C-2 th iazole); 169.72, 170.12, 170.57,
170.86 (4 × CH3CO, CH-COOCH3). For 12c (C32H37NO13S) calculated: relative m olecular
m ass 675.71, m on oisotopic m ass 675.19. MS (FAB), m/z: 676.2 [M + H]+, 698.3 [M + Na]+. For
C
32H37NO13S (675.7) calculated: 56.88% C, 5.52% H, 2.07% N; foun d: 56.64% C, 5.59% H,
1.84% N.
Methyl (R)-2-phenyl-2-({(2S,4S)-4-[(tetra-O-benzyl-α-D-galactopyranosyl)methyl]-6-(thiazol-2-yl)-
3,4-dihydro-2H-pyran-2-yl}oxy)acetate (12d ). Reaction of oxadien e 1d (110 m g, 0.16 m m ol),
vin yl eth er 10 (52 m g, 0.27 m m ol) an d Eu(fod)3 (9 m g, 0.016 m m ol) afforded 113 m g (83%)
of com poun d 12d . RF 0.28 (petroleum eth er–eth yl acetate 3:1). [α]D +13.8 (c 0.26, CHCl3).
1H NMR (CDCl3): 1.58–1.72 m , 1 H (H-1′′a); 1.85 ddd, 1 H, J(3ax,4) = 13.5, J(3ax,3eq) = 13.2,
J(2,3ax) = 6.5 (H-3ax); 2.00–2.12 m , 1 H (H-1′′b); 2.30 ddd, 1 H, J(3ax,3eq) = 13.2, J(3eq,4) =
6.7, J(2,3eq) = 2.1 (H-3eq); 2.60–2.74 m , 1 H (H-4); 3.59–4.00 m , 9 H (H-2′, H-3′, H-4′, H-5′,
H-6′a, H-6′b, CH-COOCH3); 4.06–4.21 m , 1 H (H-1′); 4.45–4.79 m , 8 H (4 × C6H5-CH2);
5.42 dd, 1 H, J(2,3ax) = 6.2, J(2,3eq) = 2.1 (H-2); 5.48 s, 1 H (CH-COOCH3); 6.02 d, 1 H,
J(4,5) = 3.5 (H-5); 7.18–7.44 m , 26 H (5 × C6H5, H-th iazole); 7.76 d, 1 H, J = 3.2 (H-th iazole).
13C NMR (CDCl3): 27.43 (C-4); 32.09 (C-1′′); 32.95 (C-3); 52.60 (CH-COOCH3); 67.74 (C-6′);
72.30 (C-1′); 73.24, 73.41, 73.51, 73.59 (4 × C6H5-CH2); 74.55, 77.14, 77.31, 77.73, 77.99
(C-2′, C-3′, C-4′, C-5′, CH-COOCH3); 98.76 (C-2); 106.80 (C-5); 118.75 (CH-th iazole);
127.56–128.79 (25 × C6H5); 136.53, 138.46, 138.63, 138.77, 138.86 (5 × ipso C6H5); 143.32
(C-6); 143.50 (CH-th iazole); 164.41 (C-2 th iazole); 171.14 (CH-COOCH3). For 12d
(C52H53NO9S) calculated: relative m olecular m ass 868.06, m on oisotopic m ass 867.34.
MS (FAB), m/z: 868.3 [M + H]+. For C52H53NO9S (868.1) calculated: 71.95% C, 6.15% H,
1.61% N; foun d: 72.14% C, 6.26% H, 1.50% N.
Methyl (R)-2-phenyl-2-({(2S,4S)-4-[(2,3:4,6-di-O-isopropylidene-α-D-mannopyranosyl)methyl]-
6-(thiazol-2-yl)-3,4-dihydro-2H-pyran-2-yl}oxy)acetate (12e). Reaction of oxadien e 1e (490 m g,
1.24 m m ol), vin yl eth er 10 (405 m g, 2.11 m m ol) an d Eu(fod)3 (130 m g, 0.124 m m ol)
afforded 600 m g (85%) of com poun d 12e. RF 0.4 (petroleum eth er–eth yl acetate 2:1). [α]D
+17.6 (c 0.24, CHCl3). 1H NMR (CDCl3): 1.34 s, 3 H ((CH3)2C); 1.46 s, 3 H ((CH3)2C); 1.54 s,
3 H ((CH3)2C); 1.58 s, 3 H ((CH3)2C); 1.82–1.95 m , 2 H (H-1′′a, H-1′′b); 2.02–2.08 m , 2 H
(H-3ax); 2.25–2.32 m , 1 H (H-3eq); 2.66–2.73 m , 1 H (H-4); 3.37–3.45 m , 1 H (H-6′a);
3.71–3.79 m , 4 H (H-5′, CH-COOCH3); 3.88–3.99 m , 3 H (H-6′b, H-3′, H-2′); 4.11 dd, 1 H,
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Štěpánek et al.:
(H-1′); 5.45–5.52 m , 2 (H-2,
J(3′,4′) = 7.6, J(4′,5′) = 7.6 (H-4′); 4.16–4.22 m , 1
H
H
CH-COOCH3); 6.07 d, 1 H, J(4,5) = 3.9 (H-5); 7.25–7.52 m , 6 H (C6H5, H-th iazole); 7.78 d, 1 H
(H-th iazole). 13C NMR (CDCl3): 18.86 (C-4); 25.52, 26.22, 28.44, 29.09 (4 × (CH3)2C); 32.72
(C-1′′); 37.30 (C-3); 52.37 (CH-COOCH3); 62.79 (C-6′); 63.66 (C-3′); 71.93 (C-2′); 72.77
(C-4′); 74.01 (C-5′); 75.01 (C-1′); 77.38 (CH-COOCH3); 97.85 (C-2); 99.57 ((CH3)2C); 103.95
(C-5); 109.36 ((CH3)2C); 118.63 (CH-th iazole); 127.50, 128.47, 128.81, 129.02, 128.74
(C6H5); 136.14 (ipso C6H5); 143.28 (CH-th iazole); 143.35 (C-6′); 169.84 (C-2 th iazole); 170.94
(CH-COOCH3). For 12e (C30H37NO9S) calculated: relative m olecular m ass 587.69, m on o-
isotopic m ass 587.22. MS (ESI), m/z: 610.4 [M + Na]+. For C30H37NO9S (587.7) calculated:
61.31% C, 6.35% H, 2.38% N; foun d: 61.43% C, 6.16% H, 2.07% N.
Meth yl (S)-2-Ph en yl-2-({(2R,4S,6S)-4-[(tetra-O-acetyl-α-D-galactopyran osyl)m eth yl]-
6-(th iazol-2-yl)tetrah ydropyran -2-yl}oxy)acetate (13)
Com poun d 11c (100 m g, 0.15 m m ol) in m eth an ol (4 m l) was h ydrogen ated over Pd/C
(10%; 60 m g) un der atm osph eric pressure for 12 h . Th e catalyst was rem oved by filtration ,
th e solven t evaporated in vacuo an d th e residue ch rom atograph ed on silica gel. Yield 80 m g
(80%) of com poun d 13. RF 0.63 (petroleum eth er–eth yl acetate 1:4). [α]D +200 (c 0.013,
CHCl3). 1H NMR (CDCl3): 1.25–1.55 m , 3 H (H-1′′a, H-3ax, H-5ax); 1.74–1.83 m , 1 H
(H-1′′b); 1.95–2.15 m , 13 H (H-4, 4 × CH3CO); 2.18–2.22 m , 1 H (H-3eq); 2.30–2.36 m , 1 H
(H-5eq); 3.73 s, 1 H (CH-COOCH3); 4.05–4.14 m , 2 H (H-5′, H-6′a); 4.23–4.30 m , 1 H
(H-6′b); 4.32–4.39 m , 1 H (H-1′); 4.81 dd, 1 H, J(5ax,6) = 11.0, J(5eq,6) = 1.9 (H-6); 4.87 dd,
1 H, J(2,3ax) = 9.0, J(2,3eq) = 1.2 (H-2); 5.15–5.19 m , 1 H (H-3′); 5.20–5.24 m , 1 H (H-2′);
5.32–5.43 m , 1 H (H-4′); 5.53 s, 1 H (CH-COOCH3); 7.30 d, 1 H, J = 3.2 (H-th iazole);
7.32–7.46 m , 5 H (C6H5); 7.73 d, 1 H, J = 3.2 (H-th iazole). 13C NMR (CDCl3): 20.63–20.74
(4 × CH3CO); 30.69 (C-4); 32.05 (C-1′′); 36.25 (C-5); 37.61 (C-3); 52.26 (CH-COOCH3); 61.28
(C-6′); 67.36 (C-2′); 67.74 (C-3′); 68.29 (C-4′); 68.59 (C-5′); 69.23 (C-1′); 75.33 (C-6); 76.75
(CH-COOCH3); 100.46 (C-2); 118.95 (CH-th iazole); 127.41, 128.54, 128.62 (C6H5); 136.13
(ipso C6H5); 142.16 (CH-th iazole); 169.67, 169.83, 169.99, 170.64, 171.14, 171.23 (4 ×
CH3CO, CH-COOCH3, C-2 th iazole). For 13 (C32H39NO13S) calculated: relative m olecular
m ass 677.73, m on oisotopic m ass 677.21. MS (FAB), m/z: 610.4 [M + Na]+. For C32H39NO13
S
(677.7) calculated: 56.71% C, 5.80% H, 2.07% N; foun d: 56.86% C, 5.69% H, 1.93% N.
Meth yl (S)-2-Ph en yl-2-({(2R,4S,6S)-4-[(α-D-galactopyran osyl)m eth yl]-
6-(th iazol-2-yl)tetrah ydropyran -2-yl}oxy)acetate (14)
Potassium cyan ide (53 m g, 0.81 m m ol) was added to a solution of com poun d 13 (850 m g,
1.26 m m ol) in m eth an ol (15 m l) an d th e reaction m ixture was stirred at room tem perature
for 1 h . After evaporation of th e solven t in vacuo, th e residue was ch rom atograph ed on
silica gel, affordin g 590 m g (93%) of com poun d 14 wh ich crystallized from m eth an ol with
on e m olecule of solven t, m .p. 206–208°C (m eth an ol). RF 0.45 (ch loroform –MeOH 20:1).
[α]D +18.1 (c 1.18, MeOH). 1H NMR (CD3OD3): 1.13–1.40 m , 3 H (H-3ax, H-4, H-5ax);
1.48–1.55 m , 1 H (H-1′′a); 1.81–1.89 m , 1 H (H-1′′b); 2.11–2.20 m , 1 H (H-3eq); 2.33–2.40 m ,
1 H (H-5eq.); 3.72 s, 3 H (CH-COOCH3); 3.28–3.89 m , 6 H (H-2′, H-3′, H-4′, H-5′, H-6′a,
H-6′b); 4.11–4.20 m , 1 H (H-1′); 4.85–4.89 m , 1 H (H-6); 4.93–4.96 m , 1 H (H-2); 5.54 s, 1 H
(CH-COOCH3); 7.34–7.46 m , 5 H (C6H5); 7.53 d, 1 H, J = 3.0 (H-th iazole); 7.75 d, 1 H,
J = 2.9 (H-th iazole). 13C NMR (CDCl3): 31.60 (C-4); 32.29 (C-1′′); 39.13 (C-5); 52.75
Collect. Czech. Chem. Commun. (Vol. 70) (2005)

Precursors of α-C-(1→3)-Disaccharides
1427
(CH-COOCH3); 62.42 (C-6′); 70.19, 71.85, 72.97, 74.15, 76.36, 78.83 (C-6, CH-COOCH3,
C-5′, C-4′, C-3′, C-2′, C-1′); 102.30 (C-2); 120.58 (CH-th iazole); 128.39, 128.47, 129.49,
129.58, 129.72 (C6H5); 137.99 (ipso C6H5); 142.78 (CH-th iazole); 173.08 (th iazole C-2);
173.84 (CH-COOCH3). For 14 (C24H31NO9S) calculated: relative m olecular m ass 509.58,
m on oisotopic m ass 509.17. MS (FAB), m/z: 510.2 [M + H]+. For C24H31NO9S (509.6) calcu-
lated: 56.57% C, 6.13% H, 2.57% N; foun d: 56.42% C, 6.22% H, 2.46% N.
X-ray Structure An alysis of Com poun d 14
Th e diffraction -quality crystals of com poun d 18 were grown from m eth an ol at room tem -
perature. Selected colourless crystal was m oun ted on glass fibres in ran dom orien tation us-
in g silicon e fat. Diffraction data were collected usin g Non ius Kappa CCD diffractom eter
(En raf–Non ius) at 150(1) K (Cryostream Cooler Oxford Cryosytem ) an d an alyzed usin g th e
HKL program package17. Th e structures were solved by th e direct, an d refin ed by full-m atrix
least-squares tech n iques (SIR92 18, SHELXL97 19). Scatterin g factors for th e n eutral atom s
used were in cluded in th e program SHELXL97. Th e h ydrogen atom s on n on -C atom s were
foun d on diferen ce Fourier m ap an d refin ed isotropically; th e h ydrogen on es on C-atom s
were kept in th eoretical position s (SHELXL97). Fin al geom etric calculation s were carried out
with SHELXL97 an d recen t version of th e PLATON program 20
Pertin en t crystallograph ic data for com poun d 14:
.
C
25H34NO10S, MW = 540.59,
m on oclin ic, space group P21 (No. 4), Z = 2, un it cell param eters a = 12.5130(3) Å,
b = 8.1850(2) Å, c = 13.6220(3) Å, α = γ = 90°, β = 103.808(1)°, V = 1354.83(6) Å–3, Dcalc
=
1.325 g cm –3, F(000) = 574, λ (MoKα) = 0.71073 Å, µ = 0.175 m m –1, θ in ran ge from 3.08 to
27.47° (6173 m easured reflection s, 6171 un ique data), R1 = 0.0460, wR2 = 0.1268 for 5857
observed reflection s (≥ 4σ(Fo)), goodn ess-of-fit S = 1.058. Th e residual electron den sity was
foun d between –0.606 an d 0.717 e Å–3. In th e crystal, on ly weak h ydrogen bon ds (2.71–3.08 Å)
were observed. Th e MeOH m olecule is con n ected with th e atom O3A (O···O distan ce is
2.71 Å).
CCDC 268332 (structure 14) con tain s th e supplem en tary crystallograph ic data for th is pa-
per. Th ese data can be obtain ed free of ch arge via www.ccdc.cam .ac.uk/con ts/retrievin g.h tm l
(or from th e Cam bridge Crystallograph ic Data Cen tre, 12, Un ion Road, Cam bridge, CB2
1EZ, UK; fax: +44 1223 336033; or deposit@ccdc.cam .ac.uk).
This work was supported by the Ministry of Education, Youth and Sports of the Czech Republic
(grant No. 6046137305), by the Grant Agency of the Czech Republic (grant No. 203/03/0497) and by
resaerch project Z 40550506. We are indebted to Dr Š. Vyskočil, Department of Organic Chemistry,
Faculty of Natural Sciences, Charles University, Prague, for his kind gift of biaryl ligands for the prep-
aration of chiral catalysts.
REFERENCES
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1995; c) Vogel P., Ferrito R., Kraehenbuehl K., Baudat A. in: Carbohydrate Mimics, Concept
and Methods (Y. Chapleur, Ed.), p. 19. Wiley-VCH, Weinheim 1998; d) Du Y.,
Collect. Czech. Chem. Commun. (Vol. 70) (2005)

1428
Štěpánek et al.:
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van der Boom J. H.: Rec. Trav. Chim. Pays-Bas 1990, 109, 583.
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17. a) Otwinowski Z., Minor W.: HKL Denzo and Scalepack Program Package. Nonius BV, Delft
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platon/.
Collect. Czech. Chem. Commun. (Vol. 70) (2005)

Erratu m
Paper publish ed in 2005, Vol. 70, No. 9, pp. 1411–1428:
Please replace th e wron g Sch em e 2 on page 1414 with th e followin g:
OH
HO
4´
OAc
AcO
OAc
6´
5´
AcO
AcO
(ii)
(i)
O
O
HO
1´
O
AcO
2´
HO
3´
AcO
6:1
AcO
3
OAc
1
2
6
(iii)
(iv)
OBn
OAc
BnO
AcO
AcO
(v)
(vi)
O
O
1c
1d
BnO
BnO
AcO
7
8
(i) allyltrimethylsilane, BF3.Et2O, MeCN, reflux 4 h;
(ii) 1. MeONa/MeOH, 2. crystallization from EtOH/Et2O; (iii) Ac2O, pyridine; (iv) NaH, BnBr, DMF
(v) 1. O3, CH2Cl2, 2. 2 phosphoranylidene-1-(thiazol-2-yl)-ethan-1-one
(vi) 1. O3, CH2Cl2, 2. Me2S, 3. 2 phosphoranylidene-1-(thiazol-2-yl)-ethan-1-one.
SCHEME 2