Ferrier rearrangement promoted by an electrochemically generated zirconium catalyst

Accepted Manuscript

Dragana Stevanović, Anka Pejović, Ivan Damljanović, Aleksandra Minić, Goran A.

Bogdanović, Mirjana Vukićević, Niko S. Radulović, Rastko D. Vukićević

PII:

S0008-6215(15)00037-3

10.1016/j.carres.2015.02.001

CAR 6941

DOI:

Reference:

To appear in: Carbohydrate Research

Received Date: 29 December 2014

Revised Date: 26 January 2015

Accepted Date: 5 February 2015

Please cite this article as: Stevanović D, Pejović A, Damljanović I, Minić A, Bogdanović GA, Vukićević

M, Radulović NS, Vukićević RD, Ferrier rearrangement promoted by an electrochemically generated

zirconium catalyst, Carbohydrate Research (2015), doi: 10.1016/j.carres.2015.02.001.

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ACCEPTED MANUSCRIPT

Ferrier rearrangement promoted by an electrochemically generated

zirconium catalyst

Dragana Stevanović ^a, Anka Pejović^a, Ivan Damljanović^a, Aleksandra Minić^a, Goran A.

Bogdanović^b, Mirjana Vukićević^c, Niko S. Radulović^d,and Rastko D. Vukićević ^a,

^aDepartment of Chemistry, Faculty of Science, University of Kragujevac, R. Domanovića 12,

34000 Kragujevac, Serbia

^bVinča Institute of Nuclear Sciences, Laboratory of Theoretical Physics and Condensed

Matter Physics, University of Belgrade, PO Box 522, 11001 Belgrade, Serbia

^cDepartment of Pharmacy, Faculty of Medicine, University of Kragujevac, S. Markovića 69,

34000 Kragujevac, Serbia

^dDepartment of Chemistry, Faculty of Science and Mathematics, University of Niš,

Višegradska 33, 18000 Niš, Serbia

Corresponding author. Tel.: +381

-

34

62

-

300268; fax: + 381

-

34

-

335040; e

-

mail: vuk@kg.ac.rs

Corresponding author. Tel.: +381

nikoradulovic@yahoo.com

-

-8049210; fax: + 381

-18

-

533 014 ; e

-

-mail:

ACCEPTED MANUSCRIPT

A B S T R A C T

In situ generated zirconium catalyst from a sacrificial zirconium anode was successfully

applied to promote Ferrier rearrangement of 3,4,5-tri-O-acetyl- -glucal and 6-deoxy-3,4-di-

O-acetyl- -glucal (3,4-di-O-acetyl- -rhamnal) in the presence of three thiols and eleven

D

L

thiophenols as nucleophiles. A simple constant current electrolysis (20 mA, 0.4 F mol^-1) of an

acetonitrile solution of lithium perchlorate (0.1 M) containing the corresponding glycal and

S-nucleophiles, using a zirconium anode and a platinum cathode resulted in the successful

synthesis of the corresponding 2,3-unsaturated peracetylated thioglycosides (with an average

anomer ratio α/β = 4.129 in the case of peracetylated

D-glucal and 8.740 in the case of L-

rhamnal). The same procedure proved to be appropriate in synthesizing dihydropyran

derivatives (“C-glycosides”) using allyltrimethylsilane as the nucleophile (only “α-anomers”

were obtained). All new compounds were fully characterized by spectral data, whereas

single-crystal X-ray analysis was performed for two thioglycosides.

Keywords

Peracetylated

D-glucal, Peracetylated L-rhamnal, Thiophenols, Pseudoglycals, Anodic

generation of catalyst, Zirconium.

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1. Introduction

Carbohydrates, as the most abundant natural compounds, have a vast number of

applications in many fields of chemistry and biochemistry.^1-3Due to their low costs,

availability in large quantities and operational versatility they represent one of the most

important classes of enantiomerically pure starting materials in organic synthesis.

Consequently, carbohydrates, particularly monosaccharides, have been intensively employed

as both the direct source of chiral carbon atoms to be embedded into the target product

structure and as powerful tools for stereoselective synthesis (as chiral auxiliaries, as

stereoselective reagents, as chiral ligands of enantioselective catalysts and as organo-

catalysts).^4-9Among many carbohydrate derivatives, unsaturated sugars are particularly

valuable intermediates in organic synthesis since they are capable of undergoing different

transformations, such as hydroxylation, hydrogenation, epoxidation, aminohydroxylation,

ozonolysis, etc.^{4, 5, 10-14}2,3-Unsaturated sugars (pseudoglycals) represent such a type of chiral

synthetic building blocks and an excellent way to synthesize these compounds is an acid

catalyzed allylic rearrangement of glycals in the presence of nucleophiles (Ferrier

rearrangement or Ferrier I reaction). Although the reaction of 3,4,6-tri-O-acetyl-D-glucal with

4-nitrophenol, giving the corresponding pseudoglucal, was known since 1962,¹⁵the reaction

currently known as Ferrier rearrangement has been described in 1969.¹⁶According to this

procedure, transformation of glycals into the corresponding 2,3-unsaturated glycosides can be

smoothly performed using BF₃·Et₂O as a catalyst. Since then a plethora of reports on this

reaction has appeared, describing Ferrier rearrangements successfully catalyzed by diverse

metallic and non-metallic catalysts, under different reaction conditions; these contributions

are well summarized in several excellent review articles.^{12, 17-20}The reaction proceeds via an

allylic oxocarbenium ion (A, Fig. 1), the formation of which is initiated by the catalytic

action of a Lewis acid (LA), and which undergoes nucleophilic attack of the suitable reagent.

The main driving force of this reaction is the relatively high stability of the formed cation,

achieved through the resonance participation of the lone pair electrons of the endocyclic

oxygen atom, as depicted in Fig. 1.

The catalytic activity of inorganic zirconium compounds (mainly ZrO₂, ZrCl₄, and ZrOCl₂)

in many organic reactions has been well recognized by synthetic chemists. As the

consequence, an array of publications describing synthetic applications of zirconium catalysts

appeared in the literature, which have recently been extensively reviewed.^21-24In continuation

of our investigations into the electrochemical generation of electrophilic reagents capable of

reacting with functionalized olefins^{25, 26}(including glycals^27-30), and the electrochemical

generation of catalysts for so-called C-acylations (from a sacrificial aluminum anode^{31, 32}), we

recently decided to examine whether zirconium species, capable of catalyzing certain

reactions, can be generated from a sacrificial zirconium anode. Any success in this regard

might overcome the apparent contribution to the improvement of a particular synthetic

procedure (Ferrier rearrangement, e.g.), but could be interesting for a wide audience of

readers. Namely, anodic dissolution of some metals represents an excellent alternative to

gradual dosage of its solid salt to the reaction media (when/where it is necessary), since the

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rate of electrochemical generation can be perfectly controlled by the simple control of the

applied current. Our preliminary results attained through the undertaken investigations have

already been reported, and it has been shown that the utilization of this technique allows for

the successful synthesis of β-oxa-, β-aza- and β-thiaketones (by hetero-Michael addition of

the corresponding conjugated carbonyl compounds and O-, N- and S-nucleophiles), as well as

2,3-unsaturated S-glycosides (by Ferrier rearrangement from the corresponding glycals).³³In

the present paper we wish to report on our detailed investigations of the anode generated

zirconium catalyst promoted Ferrier rearrangement of two peracetylated glycals – 3,4,6-tri-O-

acetyl-D-glucal (1) and 6-deoxy-3,4-di-O-acetyl-L-glucal (3,4-di-O-acetyl-L-rhamnal, 2)

using fourteen S-nucleophiles (3a-n) (Scheme 1).

2. Results and discussion

2.1. Synthesis

At the time we decided to examine the possibility of an anodic generation of zirconium

species (of any kind) capable of catalyzing certain organic reactions³³, there were only two

reports on a successful application of ZrCl₄in Ferrier rearrangement^{34, 35}(the third one

appeared in 2013³⁶). These reports prompted us to include this reaction into our studies.

Knowing that most synthetic organic chemists dislike electrochemical techniques

(particularly if the electrochemical method has any alternative among “classical” procedures),

we made efforts to invent straightforward experimental protocols, primarily those requiring

only readily available and ease to handle equipment. Thus, the reaction of glycals 1 and 2

with thiophenols 3a-n, catalyzed by the electrochemically generated zirconium species, was

designed as a simple constant current electrolysis (20 mA) of an acetonitrile solution of

lithium perchlorate containing these reactants, using an undivided electrolytic cell (a simple

round bottom glass tube; see Fig. 2), supplied with a zirconium anode and a platinum

cathode, at room temperature. Therefore, the only “electrochemical” apparatus necessary for

these experiments is a simple, inexpensive direct current supply.

When planning experiments for successful generation of a salt from a sacrificial metal

anode (to be used as a catalyst in a certain reaction) the following should be carefully

considered: (i) the solvent used should be suitable for the envisaged reaction, (ii) the solvent

must be able to dissolve an electrolyte in order to provide electroconductivity, (iii) electrolyte

ions should be inert to reactants and (iv) both the solvent and the electrolyte (conducting salt)

must be less susceptible to oxidation than the given (metal) anode. Very simple

electroanalytical measurements can undoubtedly answer the questions concerning the

conductivity of the solution and susceptibility of components to oxidation, but the choice of

all reaction media components might be done on the basis of a very general chemical

knowledge.

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Figure 1. Ferrier rearrangement

Figure 2. Electrochemical cell for the generation of a zirconium species catalyst from a

sacrificial zirconium anode

Thus, several organic solvents capable of forming electroconductive solutions are

available, and we opted for acetonitrile due to the fact that this solvent has already been used

for carrying out Ferrier rearangement^{34, 35}and its dielectric constant (ε = 38) is high enough

to enable the preparation of electroconductive solutions (several electrolytes are soluble and

undergo electrolytic dissociation in it, even a number of inorganic ones). Acetonitrile is an

aprotic solvent, very resistant to oxidation; the anodic limit in acetonitrile is dependent on the

nature of the electrolyte anion. The perchlorate anion, in its turn, is surely more resistant to

oxidation than any metal, therefore it was the anion of choice (slightly better performances

are exerted only by the tetrafluoroborate and hexafluorophosphate anions, but they are

considerably more expensive). Since reactions catalyzed by zirconium salts mainly proceed at

a 10 mol% load of the catalyst,³⁵we decided to perform one mmol scale experiments with a

0.4 Fmol^-1charge consumption (in order to generate 0.1 mmol of zirconium(IV) species). As

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already reported, our first attempt to perform “an electrochemical Ferrier rearrangement”

(using peracetylated glycal 1 and thiol 3a as reactants, Scheme 1) failed.³³Namely, an

insoluble solid appeared and the electrode voltage increased rapidly, causing an uncontrolled

increase of the solution temperature (up to boiling). This phenomenon can be attributed to the

so-called anodic passivation, arising from a coating of the zirconium oxidation product(s) at

this electrode. To overcome this, the electrolytic cell was placed into an ultrasound bath thus

providing an instantaneous removal of the coated species from the electrode surface and

moving the suspension into the bulk solution. After the necessary electricity was passed

through the solution, the mixture was irradiated for additional 30 min in the same ultrasonic

bath which resulted in the complete consumption of the starting substrate 1. TLC analysis and

¹H NMR spectra of the mixture indicated the presence of several minor and two dominant

products. Separation of the mixture by column chromatography gave anomeric pseudoglycals

1

α- and β-4a (Scheme 1) in a moderate yield (63%). As estimated by H NMR spectroscopy,

the crude mixture and fractions containing 4a were found to contain the two anomers in the

ratio α-4a/β-4a = 75:25 (= 3.000).³³

O

SR

O

SR

AcO

Zr-catalyst

+ RSH

+

AcO

OAc

3a-n

4a-n

1

O

SR

O

SR

+ RSH

+

AcO

OAc

3a-n

2

5a-n

a) CH₂(CH₂)₂CH₃, b) CH₂CO₂CH₃, c) CH₂CH₂CO₂CH₃, d) C₆H₅, e) C₆H₄-CH₃-o,

f) C₆H₄-CH₃-m, g) C₆H₄-CH₃-p, h) C₆H₄C(CH₃)₃-p, i) C₆H₄-F-o, j) C₆H₄-F-m,

k) C₆H₄-F-p, l) C₆H₄-Cl-o, m) C₆H₄-Cl-m, n) C₆H₄-Cl-p

Scheme 1. Synthesis of 2,3-unsaturated alkylthio- and arylthioglycosides from glycals 1

and 2

We extended the preliminary research, which showed that the aliphatic esters 3b and 3c,

thiophenol 3d and thiocresol 3g also reacted in a similar way (even giving higher yields of

the corresponding pseudoglycals 4b-d, g),³³by subjecting additional nine S-nucleophiles to

the above described reaction conditions. Thus, thiocresols 3e and 3f underwent the same

transformations, but, surprisingly, 4-tert-butylthiophenol (3h) and 2-fluorothiophenol (3i)

under the same conditions yielded complex mixtures consisting of several products (TLC),

1

mainly those lacking olefinic protons in their H NMR spectra. Apparently, addition

processes took place in the two cases. It is known that a zirconium catalyst (α-zirconium

sulfophenylphosphonate-methanephosphonate in the presence of LiBr) promotes addition of

ACCEPTED MANUSCRIPT

some nucleophiles (several alcohols) to the double bond of glycals, giving the corresponding

2-deoxyglycosides.³⁶However, in our case, the reaction mixtures were predominantly

composed of four different bis-thiophenylated products 6, as inferred from GC-MS analyses

of the mixtures. The molecular ions of 6 (all four isomers, Scheme 2) suggested that an

addition of the thiophenols took place following the Ferrier rearrangement. Although we

were not able to isolate pure compounds of this type by column chromatography of the

reaction mixtures, such bis-thiophenylated products were previously reported to form under

the Ferrier reaction.³⁷It is thought that minute amounts of water in the media are necessary

for this reaction to proceed as the addition of thiophenols is considered to occur via their

conjugated (Michael) addition to acyclic unsaturated aldehydes formed by hydrolysis of

pseudoglycals. These by-products are largely avoided at 1:1 molar ratios of glycal and thiol.³⁷

Scheme 2. Addition of thiophenol 3h to pseudoglycals α- and β-4h (mass spectrum of the

most abundant stereoisomer of 6h: EIMS, 70 eV, m/z (%): 544(0.8) [M]⁺, 379(17) [M-SR]⁺,

213(100) [M-2SR-H]⁺, 319(47) [M-SR-AcOH], 165(15) [SR]⁺, 153(78) [M-2SR-AcOH-H]⁺,

111(95) [M-2SR-2AcO-H]⁺, 57(37) [C₄H₉], 43(61) [Ac] ⁺).

Based on these considerations, we continued our investigations with a changed reaction

stoichiometry. Further investigations showed that this failure in the synthesis of

pseudoglycals 4h and 4i was in fact a consequence of the applied reaction conditions.

Namely, our first attempts in the electrochemical generation of zirconium catalyst species³³

were aimed to promote hetero-Michael addition. It turned out that this reaction could be

performed successfully only when using reactants in a molar ratio enone/nucleophile = 1:2

and irradiating the mixture after electrolysis for 30 min in an ultrasonic bath. By inertia (and

obviously wrongly), Ferrier rearrangement has been conducted under the same conditions and

the reaction worked well in several cases.³³However, the results obtained with 3h and 3i

forced us to search for reaction conditions which allowed avoiding the addition of the

nucleophile to the initial product. Thus, when glycal 1 reacted with thiophenols 3h and 3i in

the molar ratio 1/3 = 1:1 (with a 5% excess of the nucleophile) and by irradiating the mixture

after electrolysis in an ultrasonic bath for only 10 min (instead of 30 min), the corresponding

pseudoglycals were obtained in high yields (Table 1, entries 8, and 9). Apparently, the

prolonged ultrasonic irradiation and the excess of the nucleophile in some cases lead to the

addition of the latter to the double bond of obtained pseudoglycals via the above proposed

mechanism. It also prompted us to apply the above conditions (1/3 = 1:1, 10 min ultrasound

irradiation) to the reaction of all thiols and thiophenols (3a-n). The obtained results are listed

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in Table 1 and show that this procedure allowed for the synthesis of pseudoglycals 4a-n in

high yields with the marked predomination of α-anomers (average anomer ratio α/β = 4.129).

Table 1.

Synthesis of pseudoglycals 4a-n

Entry Nucleophile

Pseudoglycal

Yield %^a

70

Ratio α:β^b

1

2

4.000

3a

3b

α-, β-4a

85

3.000

α-, β-4b

α-, β-4c

3

4

81

89

3.000

3.762

3c

3d

α-, β-4d

α-, β-4e

α-, β-4f

α-, β-4g

5

6

7

8

85

70

73

4.882

3.762

4.556

3.167

3e

3f

3g

3h

α-, β-4h

α-, β-4i

9

77

5.250

3i

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10

11

12

13

14

70

4.882

3.545

4.882

4.556

3j

α-, β-4j

72

3k

3l

α-, β-4k

O

S

80

78

80

AcO

Cl

α-, β-4l

α-, β-4m

α-, β-4n

3m

3n

^aIsolated yield, based on the starting glycal 1.

^bEstimated by ¹H NMR spectroscopy.

Our investigations were continued by submitting 6-deoxy-3,4-di-O-acetyl-

L-glucal (3,4-di-

O-acetyl- -rhamnal, 2) to the same reaction conditions (Scheme 1). As the data listed in Table

L

2 show, this glycal readily reacted in the almost same manner as 1, allowing for the

successful synthesis of the corresponding pseudoglycals 5a-n. However, this substrate

underwent Ferrier rearrangement with a distinct higher selectivity (the average anomer ratio

α/β = 8.740).

Finally, one C-nucleophile - allyltrimethylsilane (3o) - was also employed in this reaction.

As depicted in Scheme 3, both 1 and 2 gave the corresponding dihydropyran derivatives (so-

called “C-glycosides”) in high yields, but, surprisingly, as the sole diastereoisomers (“α-

anomers”: (2R,3S,6R)-2-acetoxymethyl-6-allyl-3,6-dihydro-2H-pyran-3-yl acetate (4o) and

(2S,3R,6S)-6-allyl-2-methyl-3,6-dihydro-2H-pyran-3-yl acetate (5o), respectively).

Scheme 3. Synthesis of “C-glycosides” 4o and 5o

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We do not yet know the exact chemical composition of the catalyst, i.e., the species

generated at the anode. Since in these experiments the anode potential is not controlled,

oxidation of zirconium should take place in a way to give the product containing zirconium in

the most stable oxidation state, i.e. the species with tetravalent zirconium. Such species must

certainly represent Lewis acids, which, in our opinion, should be either zirconium- or

zirconyl perchlorate (Zr(ClO₄)₄or ZrO(ClO₄)₂, respectively). Zirconyl perchlorate is more

likely, since the used acetonitrile was not anhydrous (see Experimental), and it is well known

that Zr(IV) salts vigorously react with water giving ZrO²⁺salts.^{38, 39}Therefore, additional

investigations (the kind and the scope of which exceeds the scope of this article) are

necessary to answer this question exactly. (Electroanalytical measurements aimed to

elucidate the electrode processes, as well as examinations of the nature of the catalyst are in

progress, and the results will be published elsewhere as a separate communication.)

However, from the synthetics’ point of view, the most important characteristic of these

species is their catalytic activity, whatever the species are. Having in mind the tendency of

both Zr(IV) and ZrO²⁺ions to form mixed complexes containing different oxygen ligands

(hydroxide and alkoxy ions, water, carboxylates),^{39, 40}the catalyst action in this reaction most

likely effected through its capture of an acetate ligand from the allylic position of the glycal,

assisting the formation of oxocarbenium ions 1A or 2A (from glycals 1 and 2, respectively),

as depicted in Scheme 4.

Scheme 4. Plausible reaction mechanism

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Table 2.

Synthesis of pseudoglycals 5a-n

Entry Nucleophile

Pseudoglycal

Yield %^a

77

Ratio α:β^b

1

2

6.692

3a

3b

α-, β-5a

88

6.692

α-, β-5b

α-, β-5c

3

4

85

78

9.000

11.50

3c

3d

α-, β-5d

α-, β-5e

α-, β-5f

α-, β-5g

5

6

7

8

82

83

91

79

13.20

15.67

6.692

11.50

3e

3f

3g

3h

α-, β-5h

α-, β-5i

α-, β-5j

9

85

7.333

4.556

3i

3j

10

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11

12

13

14

96

5.667

11.50

5.667

6.692

3k

3l

α-, β-5k

87

α-, β-5l

96

3m

3n

α-, β-5m

95

α-, β-5n

^aIsolated yield, based on the starting glycal 2.

^bEstimated by ¹H NMR spectroscopy.

The configurations at the anomeric centers of 2,3-unsaturated glycosyl products formed by

the reaction under consideration were previously found to depend upon many factors such as

the substrate, the leaving group, the nucleophile, the catalyst and the reaction conditions.¹⁸

Since C-glycosides are chemically more stable than S-linked analogs, they are less likely to

rearrange under the conditions of their synthesis, and the observed products are therefore

more likely to be those formed under kinetic control. Thus, in the case of C-glycosides, the

observed diastereoselectivity in favor of the α-anomers can be ascribed to a kinetic effect

which favors axial attack at the anomeric center. Because of the reversibility of the reactions

with thiol/thiophenols under the conditions used, the anomeric α,β ratios for S-glycosides are

more likely to represent equilibrium values. Thus, we believe that the α-anomers form faster

and also represent the thermodynamic products.

2.2. Structure assignments of the new compounds

Structural assignment of the synthesized pseudoglycals was based on 1D (¹H and ¹³C) and

2D NMR experiments. Detailed analyses of NMR spectra allowed a complete assignation of

the chemical shifts for all hydrogen and carbon atoms (experimental section). The ratio of α-

1

and β-anomers was determined from the H NMR spectra of the reaction mixtures. The

signals of α- and β-anomeric H-1 hydrogens (4a-n and 5a-n) appeared at different chemical

shifts (at 5.48-5.88 and 5.32-5.76 ppm) as doublets of triplets and doublets of doublets of

doublets, respectively. The preferred conformation of the α-anomers was indicative from the

J_1,2value of ca. 3.2 Hz and J_4,5of ca. 9.5 Hz (the latter being possible only if H-4 and H-5

were both pseudo-axial) to be an equilibrating mixture of the predominant ^OH₅conformation

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5

with a small contribution of the alternate H_Oconformation (Scheme 5), or the solution

conformation could be the same as that observed in the crystal structures of α-4m and α-4n

(section 2.3). In the case of β-anomers, the value of J_4,5of, on average, 7.5 Hz suggests that

5

there is a larger contribution of H_Oin the conformational equilibrium. The chemical shifts

for pseudo-equatorial anomeric protons in the α-anomers were found to be downfield by ca.

0.1 ppm compared to that of pseudo-axial β-anomeric protons (Scheme 5).

AcO

H

O

H

OAc

AcO

SAr

H

SAr

O

AcO

H

^OH₅

⁵H_O

AcO

H

SAr

O

SAr

H

AcO

H

OAc

O

J_1,2~ 1.8 Hz

H

^OH₅

⁵H_O

Scheme 5. Equilibrium between ^OH₅and ⁵H_Oconformers of α-4 and β-4 pseudoglycals.

Different appearances (as dt and ddd) of these signals originate from the differing values of

vicinal, allylic and homoallylic coupling constants of the anomeric protons with H-2-4. The

values of vicinal coupling constants J_1,2for the α-anomers were around 3.2 Hz, while the

values of allylic and homoallylic coupling constants (J_1,3and J_1,4) were lower and mutually

similar (~ 1.7 Hz). On the other hand, β-anomers displayed slightly higher values of both

homoallylic and allylic coupling constants (J_1,3~ 2.5 Hz and J_1,4~ 2.0 Hz) compared to the

vicinal one (J_1,2~ 1.8 Hz). Due to a relatively small difference in the values of the mentioned

coupling constants of H-1 for α- and β-anomers, the assignment should be primarily relied on

chemical shift comparison rather than J_1,2.

A careful analysis of the assigned ¹³C NMR data (for a systematic comparison of these

values see Table 1 in Supplementary data) revealed a general pattern concerning the chemical

shifts of C-5 for the corresponding anomers. The shifts of C-5 of the α-4a-n series were

found to be invariably shifted upfield by ca. 7.4 ppm compared to the values of this shift in

the pseudoglycals of the β-4a-n series. Similarly, C-5 of α-5a-n resonated at ca. 7.8 ppm

higher field in comparison to C-5 in β-5a-n. At this point, it appears that the difference in the

shift of C-5 (of more than 7 ppm) could be considered as highly indicative of the

stereochemistry at C-1. We would like to propose this to be used as an additional argument

for the discernment between the α- and β-pseudoglycals.

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2.3. X-ray crystallographic analysis of 4m and 4n

The structures of 4m and 4n were confirmed by single crystal X-ray diffraction analysis

and a perspective ORTEP⁴¹plot is shown in Fig. 3. Both molecules crystallize in non-

centrosymmetric space groups and the X-ray data allowed determination of the absolute

configuration of both structures [the Flack parameters⁴²for 4m and 4n are −0.09(7) and

0.08(10), respectively]. Both molecules have very similar conformations except for the –

O2−C7(=O3) −C8 fragment and the C11-C16 phenyl ring which have significantly different

orientation in regard to the O1 six-membered ring (see Fig. 3). The shortest and the longest

C−C bonds in both crystal structures are located within the O1-ring [the C2−C3/C4−C5 bond

lengths in 4m and 4n are 1.306(4)/1.510(4) and 1.305(5)/1.534(5) Å, respectively].

Figure 3. Molecular structures of α-4m (a) and α-4n (b)

3. Conclusion

In conclusion, we described herein a new, proper and successful method for Ferrier

rearrangement of two peracetylated glycals (3,4,5-tri-O-acetyl-D-glucal, 1 and 6-deoxy-3,4-

di-O-acetyl- -glucal, 2), i.e., a new method for the preparation of the corresponding 2,3-

L

unsaturated thioglucosides, extremely valuable intermediates in the synthesis of both sugar

and non-sugar compounds. The synthesis proceeds with moderate stereoselectivity, providing

mainly the corresponding α-anomeric 2,3-unsaturated glycals (α/β = 3.00-13.20). The

described protocol, which includes the electrochemical generation of the catalyst from a

sacrificial zirconium anode, is easily performable in any organic laboratory since it does not

require complex and expensive equipment.

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4. Experimental

4.1. General remarks

All chemicals were of best commercial quality available and used as received, except that

the solvents were purified by distillation. NMR spectra were recorded on a Varian Gemini

1

200 apparatus (200 MHz) and a Bruker Avance III 400 spectrometer (400 MHz for H,

100 MHz for ¹³C), using CDCl₃as the solvent and TMS as the internal standard. Chemical

shifts are expressed in δ (ppm). 2D experiments (¹H–¹H COSY, NOESY, HSQC and HMBC)

and selective homodecoupling experiments were run on the Bruker Avance III 400

spectrometer with the usual pulse sequences. Microanalyses of carbon, hydrogen and sulfur

were carried out with a Carlo Erba 1106 model microanalyzer. The GC/MS analyses were

performed on a Hewlett–Packard 6890N gas chromatograph equipped with fused silica

capillary column DB-5MS (5% phenylmethylsiloxane, 30 m × 0.25 mm, film thickness

0.25 µm, Agilent Technologies, USA) and coupled with a 5975B mass selective detector

from the same company. Silica gel 60 on Al plates, layer thickness 0.2 mm (Merck) was used

for TLC, whereas column chromatography was performed on silica gel (0.063–20 mm,

Fluka). А bottom round glass tube (φ = 30 mm), supplied with a zirconium anode (a spiral

φ = 20 mm, made from a φ = 2 mm wire or a cuboid zirconium stick 5×5×80 mm) and a

platinum cathode (a spiral φ = 10 mm, made from a φ = 1 mm wire) was used as the

electrolytic cell (see Fig. 2). A Uniwatt, Beha Labor-Netzgerät (NG 394) was used as the

direct current supply. As the ultrasound bath an Elmasonic S30 (Elma, Germany) apparatus

was used (at a frequency of 37 kHz, with an effective ultrasonic power of 30 W and a peak of

240 W).

4.2. General procedure

The electrolytic cell was filled with 10 mL of an acetonitrile solution of LiClO₄(0.1 M), 1

mmol of glycal 1 or 2 and 1.05 mmol of the corresponding nucleophile 3a-o. The cell was

placed in the ultrasound bath and constant current electrolysis (20 mA) was run 32 min (0.4 F

mol^-1), at room temperature. After the electrolysis was finished, the reaction mixture was left

10 min in the same bath and the solvent subsequently evaporated. The residue was diluted

with 20 mL of water, the obtained mixture extracted with three 20 mL portions of ethyl

acetate and the collected organic layers dried overnight (anhydrous sodium sulfate). After

evaporation of the solvent the crude reaction product was purified by column

chromatography to give the corresponding pseudoglycals 4a-o and 5a-o, respectively. All

predominant diastereoisomers (α-anomers) were isolated as pure compounds. β-Anomers

were isolated in pure form in only five cases (β-4h, β-4i, β-4k, β-4n, and β-5m). The NMR

spectral data for the other β-anomers were estimated from the spectra of anomer mixtures.

4.3. Structure assignments of the new compounds

ACCEPTED MANUSCRIPT

Spectral data of the known compounds were in complete agreement with those published

previously (4a,^{33, 43, 44}4d,^{33, 43, 45}4g,^{33, 43, 45}4o,^{33, 44}, 5d⁴⁶and 5o⁴⁷), whereas the data

confirming the structures of the new ones follow.

4.3.1 o-Tolyl 4,6-di-O-acetyl-2,3-dideoxy-1-thio-α-D-erythro-hex-2-enopyranoside (α-

4e).

Transparent colourless crystals; mp. 51 °C; IR (KBr, ν, cm^-1): 2952, 2927, 1737, 1378,

1

1238, 1070, 1059, 1038, 786; H NMR (400 MHz, CDCl₃) δ 7.66 – 7.59 (m, 1H, H-6’), 7.22

– 7.13 (m, 3H, H-3’, 4’, 5’), 6.08 (ddd, J = 10.1, 3.2, 1.9 Hz, 1H, H-2), 5.87 (dt, J = 10.1, 1.8

Hz, 1H, H-3), 5.73 (dt, J = 3.3, 1.7 Hz, 1H, H-1), 5.38 (dq, J = 9.4, 2.0 Hz, 1H, H-4), 4.45

(ddd, J = 9.4, 5.8, 2.5 Hz, 1H, H-5), 4.29 (dd, J = 12.1, 5.8 Hz, 1H, C-6HaHb), 4.18 (dd, J =

12.1, 2.5 Hz, 1H, C-6HaHb), 2.44 (s, 3H, -CH₃), 2.11 (s, 3H, CH₃-CO-O-), 2.04 (s, 3H, CH₃-

CO-OCH₂-); ¹³C NMR (101 MHz, CDCl₃) δ 170.7 (CH₃-CO-OCH₂-), 170.3 (CH₃-CO-O-),

139.3 (C-2’), 134.2 (C-1’), 132.3 (C-6’), 130.3 (C-3’), 128.9 (C-2), 127.7 (C-4’), 127.5 (C-3),

126.7 (C-5’), 83.3 (C-1), 67.6 (C-5), 65.2 (C-4), 63.1 (C-6), 21.0 (CH₃-CO-O-), 20.8 (-CH₃),

20.7 (CH₃-CO-OCH₂-); Anal. Calcd for C₁₇H₂₀O₅S: C, 60.70; H, 5.99; O, 23.78; S, 9.53%.

Found: C, 60.65; H, 6.11; S, 9.48%.

4.3.2 o-Tolyl 4,6-di-O-acetyl-2,3-dideoxy-1-thio-β-D-erythro-hex-2-enopyranoside (β-4e).

¹H NMR (400 MHz, CDCl₃) δ 7.65 – 7.60 (m, 1H, H-6’), 7.20 – 7.11 (m, 3H, H-3’, 4’, 5’),

5.98 (dt, J = 10.2, 1.8 Hz, 1H, H-2), 5.83 (dt, J = 10.2, 2.4 Hz, 1H, H-3), 5.63 (ddd, J = 2.4,

2.0, 1.8 Hz, 1H, H-1), 5.21 (dddd, J = 7.5, 2.4, 2.0, 1.8 Hz, 1H, H-4), 4.29 (dd, J = 12.0, 5.6

Hz, 1H, C-6HaHb), 4.25 (dd, J = 12.0, 4.1 Hz, 1H, C-6HaHb), 3.90 (ddd, J = 7.5, 5.6, 4.1

Hz, 1H, H-5), 2.42 (s, 3H, -CH₃), 2.07 (s, 3H, CH₃-CO-OCH₂-), 2.06 (s, 3H, CH₃-CO-O-);

¹³C NMR (101 MHz, CDCl₃) δ 170.7 (CH₃-CO-OCH₂-), 170.1 (CH₃-CO-O-), 140.0 (C-2’),

132.9 (C-6’), 131.5 (C-1’), 130.3 (C-3’), 129.9 (C-2), 127.9 (C-4’), 127.2 (C-3), 126.4 (C-5’),

81.4 (C-1), 74.9 (C-5), 64.7 (C-4), 63.3 (C-6), 21.0 (-CH₃), 20.9 (CH₃-CO-O-), 20.7 (CH₃-

CO-OCH₂-).

4.3.3 m-Tolyl 4,6-di-O-acetyl-2,3-dideoxy-1-thio-α-D-erythro-hex-2-enopyranoside (α-

4f).

Colourless oil; IR (neat, ν, cm^-1): 3054, 3014, 2954, 1739, 1592, 1475, 1369, 1222, 1078,

1

1047, 789; H NMR (200 MHz, CDCl₃) δ 7.39 – 7.31 (m, 2H, H-2’, 6’), 7.20 (pseudo t, J =

7.8 Hz, 1H, H-5’), 7.09 (pseudo dsexset, J = 7.5, 0.7 Hz, 1H, H-4’), 6.06 (ddd, J = 10.1, 3.2,

1.9 Hz, 1H, H-2), 5.85 (dt, J = 10.1, 1.7 Hz, 1H, H-3), 5.76 (dt, J = 3.2, 1.6 Hz, 1H, H-1),

5.38 (dq, J = 9.4, 2.0 Hz, 1H, H-4), 4.46 (ddd, J = 9.4, 5.5, 2.7 Hz, 1H, H-5), 4.31 (dd, J =

12.1, 5.5 Hz, 1H, C-6HaHb), 4.21 (dd, J = 12.0, 2.7 Hz, 1H, C-6HaHb), 2.34 (s, 3H, -CH₃),

2.11 (s, 3H, CH₃-CO-O-), 2.07 (s, 3H, CH₃-CO-OCH₂-); ¹³C NMR (50 MHz, CDCl₃) δ 170.7

(CH₃-CO-OCH₂-), 170.2 (CH₃-CO-O-), 138.7 (C-3’), 134.5 (C-1’), 132.2, 128.7, 128.7,

128.6, 128.4, 127.5 (C-2’, 4’, 5’, 6’ and C-2, 3), 83.7 (C-1), 67.3 (C-5), 65.1 (C-4), 63.0 (C-

6), 21.3 (-CH₃), 20.9 (CH₃-CO-O-), 20.7 (CH₃-CO-OCH₂-); Anal. Calcd for C₁₇H₂₀O₅S: C,

60.70; H, 5.99; O, 23.78; S, 9.53%. Found: C, 60.74; H, 5.91; S, 9.58%.

ACCEPTED MANUSCRIPT

4.3.4 m-Tolyl 4,6-di-O-acetyl-2,3-dideoxy-1-thio-β-D-erythro-hex-2-enopyranoside (β-

4f).

¹H NMR (200 MHz, CDCl₃) δ 7.39 – 7.31 (m, 2H, H-2’, 6’), 7.18 (pseudo t, J = 7.2 Hz, 1H,

H-5’), 7.09 (pseudo dsextet, J = 7.5, 0.7 Hz, 1H, H-4’), 5.97 (dt, J = 10.2, 1.7 Hz, 1H, H-2),

5.82 (dt, J = 10.2, 2.4 Hz, 1H, H-3), 5.64 (ddd, J = 2.4, 2.0, 1.7 Hz, 1H, H-1), 5.21 (dddd, J =

7.4, 2.4, 2.0, 1.7 Hz, 1H, H-4), 4.32 (dd, J = 12.0, 5.2 Hz, 1H, C-6HaHb), 4.24 (dd, J = 12.0,

4.5 Hz, 1H, C-6HaHb), 3.92 (ddd, J = 7.4, 5.2, 4.5 Hz, 1H, H-5), 2.34 (s, 3H, -CH₃), 2.09 (s,

3H, CH₃-CO-OCH₂-), 2.07 (s, 3H, CH₃-CO-O-).

4.3.5

p-tert-Butylphenyl

4,6-di-O-acetyl-2,3-dideoxy-1-thio-α-D-erythro-hex-2-

enopyranoside (α-4h).

Colourless crystals; mp. 51 °C. IR (KBr, ν, cm^-1): 2961, 2905, 2870, 1740, 1592, 1368, 1223,

1

1078, 1048, 830, 788; H NMR (400 MHz, CDCl₃) δ 7.51 – 7.45 (m, AA’MM’, 2H, H-2’),

7.36 – 7.30 (m, AA’MM’, 2H, H-3’), 6.05 (ddd, J = 10.1, 3.2, 1.9 Hz, 1H, H-2), 5.84 (dt, J =

10.1, 1.8 Hz, 1H, H-3), 5.71 (dt, J = 3.2, 1.7 Hz, 1H, H-1), 5.38 (dq, J = 9.5, 2.0 Hz, 1H, H-

4), 4.48 (ddd, J = 9.5, 5.7, 2.6 Hz, 1H, H-5), 4.29 (dd, J = 12.1, 5.7 Hz, 1H, C-6HaHb), 4.22

(dd, J = 12.1, 2.6 Hz, 1H, C-6HaHb), 2.10 (s, 3H, CH₃-CO-O-), 2.07 (s, 3H, CH₃-CO-OCH₂-

), 1.31 (s, 9H, 3 × CH₃, -C(CH₃)₃); ¹³C NMR (101 MHz, CDCl₃) δ 170.7 (CH₃-CO-OCH₂-),

170.3 (CH₃-CO-O-), 151.1 (C-4’), 132.0 (C-2’), 131.2 (C-1’), 128.8 (C-2), 127.5 (C-3),

126.0 (C-3’), 84.0 (C-1), 67.4 (C-5), 65.3 (C-4), 63.2 (C-6), 34.6 (-C(CH₃)₃), 31.3 (-

C(CH₃)₃), 21.0 (CH₃-CO-O-), 20.8 (CH₃-CO-OCH₂-); Anal. Calcd for C₂₀H₂₆O₅S: C, 63.47;

H, 6.92; O, 21.14; S, 8.47%. Found: C, 63.37; H, 6.97; S, 8.49%.

4.3.6

p-tert-Butylphenyl

4,6-di-O-acetyl-2,3-dideoxy-1-thio-β-D-erythro-hex-2-

enopyranoside (β-4h).

¹H NMR (400 MHz, CDCl₃) δ 7.50 – 7.43 (m, AA’MM’, 2H, H-2’), 7.35 – 7.30 (m,

AA’MM’, 2H, H-3’), 5.97 (dt, J = 10.2, 1.8 Hz, 1H, H-2), 5.81 (dt, J = 10.2, 2.5 Hz, 1H, H-

3), 5.59 (ddd, J = 2.5, 2.0, 1.8 Hz, 1H, H-1), 5.18 (dddd, J = 7.4, 2.5, 2.0, 1.8 Hz, 1H, H-4),

4.30 (dd, J = 11.9, 5.7 Hz, 1H, C-6HaHb), 4.26 (dd, J = 11.9, 4.1 Hz, 1H, C-6HaHb), 3.90

(ddd, J = 7.4, 5.7, 4.1 Hz, 1H, H-5), 2.08 (s, 3H, CH₃-CO-OCH₂-), 2.05 (s, 3H, CH₃-CO-O-),

1.31 (s, 9H, 3 × CH₃, -C(CH₃)₃); ¹³C NMR (101 MHz, CDCl₃) δ 170.7 (CH₃-CO-OCH₂-),

170.1 (CH₃-CO-O-), 151.4 (C-4’), 132.8 (C-2’), 130.0 (C-2), 129.3 (C-1’), 127.1 (C-3),

125.8 (C-3’), 81.8 (C-1), 74.9 (C-5), 64.7 (C-4), 63.4 (C-6), 31.3 (-C(CH₃)₃), 29.7 (-

C(CH₃)₃), 21.0 (CH₃-CO-O-), 20.8 (CH₃-CO-OCH₂-).

4.3.7

o-Fluorophenyl

4,6-di-O-acetyl-2,3-dideoxy-1-thio-α-D-erythro-hex-2-

enopyranoside (α-4i).

Microcrystalline whitish solid; mp. 82 °C; IR (KBr, ν, cm^-1): 2977, 2952, 2920, 2851, 1745,

1

1645, 1475, 1383, 1242, 1224, 1068, 1043, 783, 764; H NMR (200 MHz, CDCl₃) δ 7.61 (td,

J_H-H= 7.9, 1.8 Hz, 1H, H-5’), 7.31 (dddd, J_H-H= 8.9, 7.9, 1.8 Hz, J_H-F= 5.1 Hz, 1H, H-4’),

7.17 – 7.03 (m, 2H, H-3’, 6’), 6.09 (ddd, J = 10.1, 3.1, 1.9 Hz, 1H, H-2), 5.90 (dt, J = 10.1,

1.7 Hz, 1H, H-3), 5.78 (dt, J = 3.1, 1.6 Hz, 1H, H-1), 5.40 (dq, J = 9.5, 1.9 Hz, 1H, H-4), 4.49

ACCEPTED MANUSCRIPT

(ddd, J = 9.5, 5.3, 2.5 Hz, 1H, H-5), 4.29 (dd, J = 12.2, 5.3 Hz, 1H, C-6HaHb), 4.16 (dd, J =

12.2, 2.5 Hz, 1H, C-6HaHb), 2.12 (s, 3H, CH₃-CO-O-), 2.05 (s, 3H, CH₃-CO-OCH₂-); ¹³C

1

NMR (50 MHz, CDCl₃) δ 170.6 (CH₃-CO-OCH₂-), 170.2 (CH₃-CO-O-), 162.0 (d, J_H-F

=

4

3

246.1 Hz, C-2’), 135.1 (d, J_H-F= 0.8 Hz, C-5’), 130.1 (d, J_H-F= 8.0 Hz, C-6’), 128.2, 128.1

3

2

(C-2, 3), 124.6 (d, J_H-F= 3.9 Hz, C-4’), 121.0 (d, J_H-F= 18.2 Hz, C-1’), 115.8 (d, J_H-F

=

4

23.0 Hz, C-3’), 82.9 (d, J_H-F= 1.7 Hz, C-1), 67.4 (C-5), 65.0 (C-4), 62.8 (C-6), 20.9 (CH₃-

CO-O-), 20.6 (CH₃-CO-OCH₂-); Anal. Calcd for C₁₆H₁₇FO₅S: C, 56.46; H, 5.03; F, 5.58; O,

23.50; S, 9.42%. Found: C, 56.37; H, 4.92; S, 9.37%.

4.3.8

o-Fluorophenyl

4,6-di-O-acetyl-2,3-dideoxy-1-thio-β-D-erythro-hex-2-

enopyranoside (β-4i).

¹H NMR (400 MHz, CDCl₃) δ 7.63 (td, J = 7.6, 1.8 Hz, 1H, H-5’), 7.32 (dddd, J_H-H= 8.1,

7.6, 1.8 Hz, J_H-F= 5.1 Hz,1H, H-4’), 7.14 – 7.05 (m, 2H, H-3’, 6’), 6.00 (dt, J = 10.2, 1.8 Hz,

1H, H-2), 5.82 (dt, J = 10.2, 2.4 Hz, 1H, H-3), 5.65 (ddd, J = 2.4, 2.0, 1.8 Hz, 1H, H-1), 5.11

(dddd, J = 7.4, 2.4, 2.0, 1.8 Hz, 1H, H-4), 4.34 – 4.25 (m, ABX, 2H, C-6HaHb), 3.89

(pseudo dt, J = 7.4, 4.8 Hz, 1H, H-5), 2.09 (s, 3H, CH₃-CO-OCH₂-), 2.06 (s, 3H, CH₃-CO-O-

); ¹³C NMR (101 MHz, CDCl₃) δ 170.7 (CH₃-CO-OCH₂-), 170.1 (CH₃-CO-O-), 162.1 (d,

4

3

¹J_H-F=246.7 Hz, C-2’), 135.9 (d, J_H-F= 0.5 Hz, C-5’), 130.5 (d, J_H-F= 8.0 Hz, C-4’), 129.5

(C-2), 128.2 (d, ²J_H-F= 10.5 Hz, C-1’), 127.6 (C-3), 124.3 (d, ³J_H-F= 3.8 Hz, C-6’), 115.8 (d,

²J_H-F= 23.1 Hz, C-3’), 80.8 (d, J_H-F= 1.7 Hz, C-1), 74.8 (C-5), 64.3 (C-4), 63.2 (C-6), 21.0

4

(CH₃-CO-O-), 20.8 (CH₃-CO-OCH₂-).

4.3.9

m-Fluorophenyl

4,6-di-O-acetyl-2,3-dideoxy-1-thio-α-D-erythro-hex-2-

enopyranoside (α-4j).

Microcrystalline whitish solid; mp. 58 °C; IR (KBr, ν, cm^-1): 3071, 2995, 2927, 1742, 1597,

1

1580, 1475, 1371, 1255, 1238, 1219, 1085, 1071, 1034, 881, 786; H NMR (200 MHz,

CDCl₃) δ 7.39 – 7.21 (m, 3H, Ar), 7.06 – 6.91 (m, 1H, Ar), 6.05 (ddd, J = 10.1, 3.1, 1.8 Hz,

1H, H-2), 5.89 (dt, J = 10.1, 1.7 Hz, 1H, H-3), 5.78 (dt, J = 3.1, 1.8 Hz, 1H, H-1), 5.37 (dq, J

= 9.4, 1.9 Hz, 1H, H-4), 4.46 (ddd, J = 9.4, 5.8, 3.3 Hz, 1H, H-5), 4.29 (dd, J = 12.0, 5.8 Hz,

1H, C-6HaHb), 4.20 (dd, J = 12.0, 3.3 Hz, 1H, C-6HaHb), 2.12 (s, 3H, CH₃-CO-O-), 2.09 (s,

3H, CH₃-CO-OCH₂-). ¹³C NMR (50 MHz, CDCl₃) δ 170.7 (CH₃-CO-OCH₂-), 170.1 (CH₃-

1

3

CO-O-), 162.5 (d, J_H-F= 248.6 Hz, C-3’), 136.9 (d, J_H-F= 8.0 Hz, C-1’), 130.0 (d, J_H-F

=

8.5 Hz, C-5’), 128.1 (C-2), 128.0 (C-3), 126.9 (d, ⁴J_H-F= 3.1 Hz, C-6’), 118.4 (d, ²J_H-F= 22.6

Hz, C-2’), 114.5 (d, J_H-F= 21.2 Hz, C-4’), 83.3 (C-1), 67.4 (C-5), 65.1 (C-4), 63.0 (C-6),

2

20.9 (CH₃-CO-O-), 20.6 (CH₃-CO-OCH₂-); Anal. Calcd for C₁₆H₁₇FO₅S: C, 56.46; H, 5.03;

F, 5.58; O, 23.50; S, 9.42%. Found: C, 56.45; H, 5.03; S, 9.44%.

4.3.10

m-Fluorophenyl

4,6-di-O-acetyl-2,3-dideoxy-1-thio-β-D-erythro-hex-2-

enopyranoside (β-4j).

¹H NMR (400 MHz, CDCl₃) δ 7.36 – 7.30 (m, 1H, H-2’), 7.30 – 7.21 (m, 2H, H-5’, 6’), 7.03

– 6.93 (m, 1H, H-4’), 5.96 (dt, J = 10.2, 1.7 Hz, 1H, H-2), 5.86 (dt, J = 10.2, 2.4 Hz, 1H, H-

3), 5.67 (ddd, J = 2.4, 2.0, 1.7 Hz, 1H, H-1), 5.22 (dddd, J = 7.6, 2.4, 2.0, 1.7 Hz, 1H, H-4),

4.34 – 4.28 (m, ABX, 2H, C-6HaHb), 3.95 (pseudo dt, J = 7.6, 4.8 Hz, 1H, H-5), 2.11 (s, 3H,

ACCEPTED MANUSCRIPT

CH₃-CO-OCH₂-), 2.08 (s, 3H, CH₃-CO-O-); ¹³C NMR (101 MHz, CDCl₃) δ 170.8 (CH₃-CO-

1

3

OCH₂-), 170.1 (CH₃-CO-O-), 162.5 (d, J_H-F= 247.9 Hz, C-3’), 135.4 (d, J_H-F= 8.0 Hz, C-

3

4

1’) 129.9 (d, J_H-F= 8.3 Hz, C-5’), 129.4 (C-2), 127.7 (C-3), 127.5 (d, J_H-F= 3.1 Hz, C-6’),

118.8 (d, ²J_H-F= 22.8 Hz, C-2’), 114.8 (d, ²J_H-F= 21.2 Hz, C-4’), 81.2 (C-1), 74.9 (C-5), 64.4

(C-4), 63.1 (C-6), 21.0 (CH₃-CO-O-), 20.7 (CH₃-CO-OCH₂-).

4.3.11

p-Fluorophenyl

4,6-di-O-acetyl-2,3-dideoxy-1-thio-α-D-erythro-hex-2-

enopyranoside (α-4k).

Yellowish oil; IR (neat, ν, cm^-1): 3096, 3068, 2955, 1738, 1589, 1490, 1369, 1219, 1077,

1046, 1014, 831; ¹H NMR (200 MHz, CDCl₃) δ 7.62 – 7.47 (m, AA’MM’, 2H, H-2’), 7.12 –

6.91 (m, AA’MM’, 2H, H-3’), 6.05 (ddd, J = 10.1, 3.1, 1.9 Hz, 1H, H-2), 5.87 (dt, J = 10.1,

1.7 Hz, 1H, H-3), 5.66 (dt, J = 3.1, 1.6 Hz, 1H, H-1), 5.38 (dq, J = 9.5, 1.9 Hz, 1H, H-4), 4.47

(ddd, J = 9.5, 4.4, 3.7 Hz, 1H, H-5), 4.28 (dd, J = 12.2, 4.4 Hz, 1H, C-6HaHb), 4.23 (dd, J =

12.2, 3.7 Hz, 1H, C-6HaHb), 2.12 (s, 3H, CH₃-CO-O-), 2.10 (s, 3H, CH₃-CO-OCH₂-); ¹³C

NMR (50 MHz, CDCl₃) δ 170.6 (CH₃-CO-OCH₂-), 170.2 (CH₃-CO-O-), 162.7 (d, J = 248.2

Hz, C-4’), 134.5 (d, J = 8.2 Hz, C-2’), 129. 7 (d, J = 3.4 Hz, C-1’), 128.3 (C-2), 127.8 (C-3),

116.0 (d, J = 21.9 Hz, C-3’), 84.1 (C-1), 67.3 (C-5), 65.1 (C-4), 63.2 (C-6), 20.9 (CH₃-CO-O-

), 20.7 (CH₃-CO-OCH₂-); Anal. Calcd for C₁₆H₁₇FO₅S: C, 56.46; H, 5.03; F, 5.58; O, 23.50;

S, 9.42%. Found: C, 56.42; H, 5.05; S, 9.44%.

4.3.12

p-Fluorophenyl

4,6-di-O-acetyl-2,3-dideoxy-1-thio-β-D-erythro-hex-2-

enopyranoside (β-4k).

¹H NMR (200 MHz, CDCl₃) δ 7.59 – 7.46 (m, AA’MM’, 2H, H-2’), 7.08 – 6.93 (m,

AA’MM’, 2H, H-3’), 5.93 (dt, J = 10.1, 1.7 Hz, 1H, H-2), 5.79 (dt, J = 10.1, 2.2 Hz, 1H, H-

3), 5.55 (ddd, J = 2.2, 2.1, 1.7 Hz, 1H, H-1), 5.13 (dddd, J = 7.6, 2.3, 2.2, 1.7 Hz, 1H, H-4),

4.27 – 4.23 (m, ABX, 2H, C-6HaHb), 3.88 (pseudo dt, J = 7.6, 4.6 Hz, 1H, H-5), 2.10 (s, 3H,

CH₃-CO-OCH₂-), 2.06 (s, 3H, CH₃-CO-O-).

4.3.13

o-Chlorophenyl

4,6-di-O-acetyl-2,3-dideoxy-1-thio-α-D-erythro-hex-2-

enopyranoside (α-4l).

Microcrystalline whitish solid; mp. 63 °C. IR (KBr, ν, cm^-1): 2953, 2927, 2852, 1735, 1455,

1384, 1252, 1238, 1222, 1069, 1035, 787, 757; ¹H NMR (200 MHz, CDCl₃) δ 7.75 – 7.64 (m,

ABMX, 1H, H-3’), 7.46 – 7.35 (m, ABMX, 1H, H-6’), 7.31 – 7.15 (m, ABMX, 2H, H-4’,

5’), 6.10 (ddd, J = 9.9, 3.3, 1.9 Hz, 1H, H-2), 5.91 (dt, J = 9.9, 1.7 Hz, 1H, H-3), 5.87 (dt, J =

3.3, 1.6 Hz, 1H, H-1), 5.41 (dq, J = 9.4, 1.9 Hz, 1H, H-4), 4.45 (ddd, J = 9.4, 5.4, 2.4 Hz, 1H,

H-5), 4.31 (dd, J = 12.1, 5.4 Hz, 1H, C-6HaHb), 4.16 (dd, J = 12.1, 2.4 Hz, 1H, C-6HaHb),

2.12 (s, 3H, CH₃-CO-O-), 2.03 (s, 3H, CH₃-CO-OCH₂-); ¹³C NMR (50 MHz, CDCl₃) δ 170.6

(CH₃-CO-OCH₂-), 170.2 (CH₃-CO-O-), 135.3 (C-2’), 133.9 (C-1’), 132.5 (C-3’), 129.7 (C-

6’), 128.4 (C-2), 128.3 (C-3), 128.1 (C-5’), 127.3 (C-4’), 82.3 (C-1), 67.7 (C-5), 64.9 (C-4),

62.8 (C-6), 20.9 (CH₃-CO-O-), 20.7 (CH₃-CO-OCH₂-); Anal. Calcd for C₁₆H₁₇ClO₅S: C,

53.86; H, 4.80; Cl, 9.94; O, 22.42; S, 8.99%. Found: C, 53.91; H, 4.76; S, 9.07%.

ACCEPTED MANUSCRIPT

4.3.14

o-Chlorophenyl

4,6-di-O-acetyl-2,3-dideoxy-1-thio-β-D-erythro-hex-2-

enopyranoside (β-4l).

¹H NMR (400 MHz, CDCl₃) δ 7.75 – 7.69 (m, ABMX, 1H, H-3’), 7.46 – 7.36 (m, ABMX,

1H, H-6’), 7.24 – 7.15 (m, ABMX, 2H, H-4’, 5’), 6.05 (dt, J = 10.2, 1.8 Hz, 1H, H-2), 5.90

(dt, J = 10.2, 2.5 Hz, 1H, H-3), 5.76 (ddd, J = 2.5, 2.2, 1.8 Hz, 1H, H-1), 5.23 (dddd, J = 7.1,

2.5, 2.2, 1.8 Hz, 1H, H-4), 4.34 – 4.29 (m, ABX, 2H, C-6HaHb), 3.97 (pseudo dt, J = 7.1,

5.2 Hz, 1H, H-5), 2.08 (s, 3H, CH₃-CO-OCH₂-), 2.07 (s, 3H, CH₃-CO-O-); ¹³C NMR (101

MHz, CDCl₃) δ 170.7 (CH₃-CO-OCH₂-), 170.2(CH₃-CO-O-), 135.2 (C-2’), 132.9 (C-1’),

132.6 (C-3’), 129.7 (C-6’), 129.3 (C-2), 128.5 (C-5’), 127.5 (C-3), 127.1 (C-4’), 80.3 (C-1),

74.7 (C-5), 64.4 (C-4), 63.2 (C-6), 21.0 (CH₃-CO-O-), 20.8 (CH₃-CO-OCH₂-).

4.3.15

m-Chlorophenyl

4,6-di-O-acetyl-2,3-dideoxy-1-thio-α-D-erythro-hex-2-

enopyranoside (α-4m).

Colourless crystals; mp. 69 °C; IR (KBr, ν, cm^-1): 2991, 2954, 2929, 1742, 1729, 1578, 1403,

1

1384, 1377, 1228, 1207, 1068, 1048, 1015, 784, 773; H NMR (200 MHz, CDCl₃) δ 7.58

(pseudo td, J = 1.7, 0.6 Hz, 1H, H-2’), 7.48 – 7.36 (m, 1H, Ar), 7.30 – 7.21 (m, 2H, Ar), 6.05

(ddd, J = 10.1, 3.1, 1.8 Hz, 1H, H-2), 5.88 (dt, J = 10.1, 1.7 Hz, 1H, H-3), 5.77 (dt, J = 3.1,

1.9 Hz, 1H, H-1), 5.36 (dq, J = 9.4, 1.9 Hz, 1H, H-4), 4.44 (ddd, J = 9.4, 5.5, 3.4 Hz, 1H, H-

5), 4.29 (dd, J = 12.1, 5.5 Hz, 1H, C-6HaHb), 4.23 (dd, J = 12.1, 3.4 Hz, 1H, C-6HaHb),

2.12 (s, 3H, CH₃-CO-O-), 2.09 (s, 3H, CH₃-CO-OCH₂-); ¹³C NMR (50 MHz, CDCl₃) δ 170.6

(CH₃-CO-OCH₂-), 170.1 (CH₃-CO-O-), 136.8 (C-3’), 134.5 (C-1’), 131.2, 129.9, 129.5,

128.1, 128.0, 127.7 (C-2’, 4’, 5’, 6’ and C-2, 3), 83.4 (C-1), 67.5 (C-5), 65.0 (C-4), 63.0 (C-

6), 20.9 (CH₃-CO-O-), 20.7 (CH₃-CO-OCH₂-); Anal. Calcd for C₁₆H₁₇ClO₅S: C, 53.86; H,

4.80; Cl, 9.94; O, 22.42; S, 8.99%. Found: C, 53.79; H, 4.84; S, 8.95%.

4.3.16

m-Chlorophenyl

4,6-di-O-acetyl-2,3-dideoxy-1-thio-β-D-erythro-hex-2-

enopyranoside (β-4m).

¹H NMR (200 MHz, CDCl₃) δ 7.60 – 7.56 (m, 1H, Ar), 7.40 – 7.36 (m, 1H, Ar), 7.25 – 7.18

(m, 2H, Ar), 5.95 (dt, J = 10.2, 1.6 Hz, 1H, H-2), 5.82 (dt, J = 10.2, 2.2 Hz, 1H, H-3), 5.67

(ddd, J = 2.2, 2.0, 1.6 Hz, 1H, H-1), 5.22 (dddd, J = 7.5, 2.2, 2.0, 1.6 Hz, 1H, H-4), 4.31 –

4.26 (m, ABX, 2H, C-6HaHb), 3.95 (pseudo dt, J = 7.5, 4.8 Hz, 1H, H-5), 2.12 (s, 3H, CH₃-

CO-OCH₂-), 2.07 (s, 3H, CH₃-CO-O-).

4.3.17

p-Chlorophenyl

4,6-di-O-acetyl-2,3-dideoxy-1-thio-α-D-erythro-hex-2-

enopyranoside (α-4n).

Colourless crystals; mp. 71 °C; IR (KBr, ν, cm^-1): 2960, 2927, 2903, 1746, 1731, 1478, 1374,

1

1060, 1043, 1014, 830, 818, 785; H NMR (400 MHz, CDCl₃) δ 7.51 – 7.46 (m, AA’MM’,

2H, H-2’), 7.31 – 7.26 (m, AA’MM’, 2H, H-3’), 6.04 (ddd, J = 10.1, 3.2, 1.9 Hz, 1H, H-2),

5.88 (dt, J = 10.1, 1.8 Hz, 1H, H-3), 5.71 (dt, J = 3.2, 1.7 Hz, 1H, H-1), 5.38 (dq, J = 9.5, 2.0

Hz, 1H, H-4), 4.44 (ddd, J = 9.5, 5.6, 2.9 Hz, 1H, H-5), 4.27 (dd, J = 12.1, 5.6 Hz, 1H, C-

6HaHb), 4.22 (dd, J = 12.1, 2.9 Hz, 1H, C-6HaHb), 2.11 (s, 3H, CH₃-CO-O-), 2.08 (s, 3H,

CH₃-CO-OCH₂-); ¹³C NMR (101 MHz, CDCl₃) δ 170.7 (CH₃-CO-OCH₂-), 170.3 (CH₃-CO-

ACCEPTED MANUSCRIPT

O-), 134.0 (C-4’), 133.3 (C-1’), 133.1 (C-2’), 129.1 (C-3’), 128.2 (C-2), 128.0 (C-3), 83.7 (C-

1), 67.4 (C-5), 65.1 (C-4), 63.1 (C-6), 21.0 (CH₃-CO-O-), 20.8 (CH₃-CO-OCH₂-); Anal.

Calcd for C₁₆H₁₇ClO₅S: C, 53.86; H, 4.80; Cl, 9.94; O, 22.42; S, 8.99%. Found: C, 53.84; H,

4.78; S, 9.04%.

4.3.18

p-Chlorophenyl

4,6-di-O-acetyl-2,3-dideoxy-1-thio-β-D-erythro-hex-2-

enopyranoside (β-4n).

¹H NMR (400 MHz, CDCl₃) δ 7.50 – 7.45 (m, AA’MM’, 2H, H-2’), 7.30 – 7.25 (m,

AA’MM’, 2H, H-3’), 5.93 (dt, J = 10.2, 1.8 Hz, 1H, H-2), 5.83 (dt, J = 10.2, 2.4 Hz, 1H, H-

3), 5.60 (ddd, J = 2.4, 2.0, 1.8 Hz, 1H, H-1), 5.18 (dddd, J = 7.5, 2.4, 2.0, 1.7 Hz, 1H, H-4),

4.31 – 4.28 (m, ABX, 2H, C-6HaHb), 3.91 (ddd, J = 7.5, 5.1, 4.4 Hz, 1H, H-5), 2.10 (s, 3H,

CH₃-CO-OCH₂-), 2.07 (s, 3H, CH₃-CO-O-); ¹³C NMR (101 MHz, CDCl₃) δ 170.7 (CH₃-CO-

OCH₂-), 170.1 (CH₃-CO-O-), 134.3 (C-4’), 134.1 (C-2’), 131.1 (C-1’), 129.5 (C-2), 128.9

(C-3’), 127.6 (C-3), 81.3(C-1), 74.9 (C-5), 64.4 (C-4), 63.2 (C-6), 21.0 (CH₃-CO-O-), 20.8

(CH₃-CO-OCH₂-).

4.3.19 Butyl 4-O-acetyl-1-thio-2,4,6-tridideoxy-α-L-erythro-hex-2-enopyranoside (α-5a).

Colourless oil; IR (neat, ν, cm^-1): 2958, 2931, 2874, 1741, 1372, 1231, 1091, 1060, 1039,

916, 792; ¹H NMR (200 MHz, CDCl₃) δ 5.91 (ddd, J = 10.1, 3.0, 1.8 Hz, 1H, H-2), 5.73 (dt,

J = 10.1, 1.7 Hz, 1H, H-3), 5.48 (dt, J = 3.0, 1.8 Hz, 1H, H-1), 5.11 (dq, J = 9.0, 1.9 Hz, 1H,

H-4), 4.15 (dq, J = 9.0, 6.3 Hz, 1H, H-5), 2.81 – 2.55 (m, 2H, SCH₂), 2.09 (s, 3H, OCOCH₃),

1.71 – 1.52 (m, 2H, CH₂), 1.52 – 1.31 (m, 2H, CH₂), 1.23 (d, J = 6.3 Hz, 3H, CH₃), 0.92 (t, J

= 7.2 Hz, 3H, CH₃); ¹³C NMR (50 MHz, CDCl₃) δ 170.5 (CH₃-CO-O-), 129.2, 127.1 (C-2,

3), 80.2 (C-1), 70.8 (C-4), 64.9 (C-5), 32.2 (CH₂), 31.8 (CH₂), 21.9 (CH₂CH₃), 21.0 (CH₃-

CO-O-), 17.9 (CH₃), 13.6 (CH₂CH₃); Anal. Calcd for C₁₂H₂₀O₃S: C, 58.98; H, 8.25; O,

19.64; S, 13.12%. Found: C, 59.07; H, 8.31; S, 13.07%.

4.3.20 Methyl glycolyl (2’-Methoxy-2’-oxoethyl) 4-O-acetyl-1-thio-2,4,6-tridideoxy-α-

L-

erythro-hex-2-enopyranoside (α-5b).

Colourless oil; IR (neat, ν, cm^-1): 2981, 2953, 2936, 1734, 1436, 1372, 1280, 1231, 1090,

1064, 1039, 917, 782; ¹H NMR (200 MHz, CDCl₃) δ 5.92 (ddd, J = 10.1, 2.9, 1.7 Hz, 1H, H-

2), 5.80 (dt, J = 10.1, 1.6 Hz, 1H, H-3), 5.66 (ddd, J = 2.9, 2.1, 1.6 Hz, 1H, H-1), 5.12 (dq, J

= 9.0, 1.8 Hz, 1H, H-4), 4.11 (dq, J = 9.0, 6.2 Hz, 1H, H-5), 3.75 (s, 3H, COOCH₃), 3.50 (d, J

= 15.1 Hz, 1H, SCHaHbCO), 3.29 (d, J = 15.1 Hz, 1H, SCHaHbCO), 2.10 (s, 3H,

OCOCH₃), 1.23 (d, J = 6.2 Hz, 3H, CH₃); ¹³C NMR (50 MHz, CDCl₃) δ 170.8 (-CO-O-CH₃),

170.3 (CH₃-CO-O-), 128.3, 127.9 (C-2, 3), 79.8 (C-1), 70.6 (C-4), 65.2 (C-5), 52.4 (-CO-O-

CH₃), 32.7 (CH₂), 20.9 (CH₃-CO-O-), 17.8 (CH₃); Anal. Calcd for C₁₁H₁₆O₅S: C, 50.75; H,

6.20; O, 30.73; S, 12.32%. Found: C, 50.67; H, 6.11; S, 12.38%.

4.3.21 3’-Methoxy-3’-oxopropyl 4-O-acetyl-1-thio-2,4,6-tridideoxy-α-

enopyranoside (α-5c).

L-erythro-hex-2-

ACCEPTED MANUSCRIPT

Yellow viscous oil; IR (neat, ν, cm^-1): 2979, 2953, 2935, 1734, 1436, 1372, 1231, 1148,

1

1090, 1061, 1039, 916, 785; H NMR (200 MHz, CDCl₃) δ 5.89 (ddd, J = 10.1, 2.9, 1.8 Hz,

1H, H-2), 5.75 (dt, J = 10.2, 1.7 Hz, 1H, H-3), 5.51 (dt, J = 2.9, 2.1 Hz, 1H, H-1), 5.11 (dq, J

= 9.0, 1.9 Hz, 1H, H-4), 4.12 (dq, J = 9.0, 6.3 Hz, 1H, H-5), 3.71 (s, 3H, COCH₃), 3.04 – 2.60

(m, A₂B_2,4H, SCH₂CH₂CO), 2.09 (s, 3H, OCOCH₃), 1.24 (d, J = 6.3 Hz, 3H, CH₃); ¹³C

NMR (50 MHz, CDCl₃) δ 172.2 (-CO-O-CH₃), 170.4 (CH₃-CO-O-), 128.7, 127.6 (C-2, 3),

80.6 (C-1), 70.7 (C-4), 65.0 (C-5), 51.7 (-CO-O-CH₃), 35.3 (SCH₂CH₂CO), 27.2

(SCH₂CH₂CO), 21.0 (O-CO-CH₃), 17.8 (CH₃); Anal. Calcd for C₁₂H₁₈O₅S: C, 52.54; H,

6.61; O, 29.16; S, 11.69%. Found: C, 52.48; H, 6.70; S, 11.73%.

4.3.22 o-Tolyl 4-O-acetyl-1-thio-2,4,6-tridideoxy-α-L-erythro-hex-2-enopyranoside (α-

5e).

Microcrystalline colourless solid; mp. 46 °C; IR (KBr, ν, cm^-1): 3017, 2978, 2932, 2898,

1738, 1469, 1454, 1375, 1241, 1091, 1057, 1042, 781; ¹H NMR (200 MHz, CDCl₃) δ 7.66 –

7.55 (m, 1H, H-6’), 7.22 – 7.12 (m, 3H, H-3’, 4’, 5’), 6.05 (ddd, J = 10.1, 3.1, 1.9 Hz, 1H, H-

2), 5.83 (dt, J = 10.1, 1.7 Hz, 1H, H-3), 5.69 (dt, J = 3.2, 1.6 Hz, 1H, H-1), 5.15 (dq, J = 9.0,

1.9 Hz, 1H, H-4), 4.27 (dq, J = 9.0, 6.2 Hz, 1H, H-5), 2.42 (s, 3H, CH₃), 2.11 (s, 3H,

OCOCH₃), 1.26 (d, J = 6.2 Hz, 3H, CH₃); ¹³C NMR (50 MHz, CDCl₃) δ 170.4 (CH₃-CO-O-),

139.0 (C-2’), 134.7 (C-1’), 131.7, 130.1, 128.8, 127.9, 127.3, 126.6 (C-3’, 4’, 5’, 6’ and C-2,

3), 83.1 (C-1), 70.7 (C-4), 65.6 (C-5), 21.0 (OCOCH₃), 20.7 (CH₃), 18.0 (CH₃); Anal. Calcd

for C₁₅H₁₈O₃S: C, 64.72; H, 6.52; O, 17.24; S, 11.52%. Found: C, 64.66; H, 6.61; S, 11.47%.

4.3.23 o-Tolyl 4-O-acetyl-1-thio-2,4,6-tridideoxy-β-L-erythro-hex-2-enopyranoside (β-

5e).

¹H NMR (200 MHz, CDCl₃) δ 7.67 – 7.55 (m, 1H, H-6’), 7.24 – 7.12 (m, 3H, H-3’, 4’, 5’),

5.95 (dt, J = 10.2, 1.7 Hz, 1H, H-2), 5.80 (dt, J = 10.2, 2.2 Hz, 1H, H-3), 5.61 (ddd, J = 2.5,

2.2, 1.7 Hz, 1H, H-1), 5.04 (dddd, J = 7.4, 2.5, 2.2, 1.7 Hz, 1H, H-4), 3.78 (dq, J = 7.4, 6.3

Hz, 1H, H-5), 2.42 (s, 3H, CH₃), 2.07 (s, 3H, OCOCH₃), 1.33 (d, J = 6.3 Hz, 3H, CH₃).

4.3.24 m-Tolyl 4-O-acetyl-1-thio-2,4,6-tridideoxy-α-L-erythro-hex-2-enopyranoside (α-

5f).

Colourless oil; IR (neat, ν, cm^-1): 3052, 2979, 2932, 1743, 1592, 1475, 1372, 1235, 1092,

1063, 1041, 787; ¹H NMR (200 MHz, CDCl₃) δ 7.36 – 7.29 (m, 2H, H-2’, 6’), 7.20 (pseudo t,

J = 7.8 Hz, 1H, H-5’), 7.07 (pseudo dsextet, J = 7.5, 0.7 Hz, 1H, 4’), 6.02 (ddd, J = 10.1, 3.1,

1.9 Hz, 1H, H-2), 5.82 (dt, J = 10.1, 1.7 Hz, 1H, H-3), 5.71 (dt, J = 3.1, 1.6 Hz, 1H, H-1),

5.15 (dq, J = 9.1, 1.9 Hz, 1H, H-4), 4.27 (dq, J = 9.1, 6.2 Hz, 1H, H-5), 2.34 (s, 3H, CH₃),

2.11 (s, 3H, OCOCH₃), 1.28 (d, J = 6.2 Hz, 3H, CH₃); ¹³C NMR (50 MHz, CDCl₃) δ 170.4

(CH₃-CO-O-), 138.7 (C-3’), 135.1 (C-1’), 132.0, 128.7, 128.6, 128.3, 128.2, 128.0 (C-2’, 4’,

5’, 6’ and C-2, 3), 83.6 (C-1), 70.7 (C-4), 65.4 (C-5), 21.3 (CH₃), 21.1 (OCOCH₃), 18.0

(CH₃); Anal. Calcd for C₁₅H₁₈O₃S: C, 64.72; H, 6.52; O, 17.24; S, 11.52%. Found: C, 64.74;

H, 6.50; S, 11.51%.

ACCEPTED MANUSCRIPT

4.3.25 m-Tolyl 4-O-acetyl-1-thio-2,4,6-tridideoxy-β-L-erythro-hex-2-enopyranoside (β-

5f).

¹H NMR (200 MHz, CDCl₃) δ 7.36 – 7.29 (m, 2H, H-2’, 6’), 7.20 (pseudo t, J = 7.8 Hz, 1H,

H-5’), 7.07 (pseudo dsextet, J = 7.5, 0.7 Hz, 1H, H-4’), 5.93 (dt, J = 10.2, 1.7 Hz, 1H, H-2),

5.77 (dt, J = 10.2, 2.4 Hz, 1H, H-3), 5.60 (ddd, J = 2.4, 2.0, 1.7 Hz, 1H, H-1), 5.02 (dddd, J =

7.9, 2.4, 2.0, 1.7 Hz, 1H, H-4), 3.78 (dq, J = 7.9, 6.4 Hz, 1H, H-5), 2.34 (s, 3H, CH₃), 2.06 (s,

3H, OCOCH₃), 1.34 (d, J = 6.4 Hz, 3H, CH₃).

4.3.26 p-Tolyl 4-O-acetyl-1-thio-2,4,6-tridideoxy-α-L-erythro-hex-2-enopyranoside (α-

5g).

Whitish microcrystalline solid; mp. 77 °C; IR (KBr, ν, cm^-1): 2982, 2970, 2929, 2874, 1728,

1

1494, 1396, 1373, 1237, 1096, 1071, 1042, 805, 779; H NMR (200 MHz, CDCl₃) δ 7.45 –

7.37 (m, AA’MM’, 2H, H-2’), 7.12 (m, AA’MM’, 2H, H-3’), 6.02 (ddd, J = 10.1, 3.1, 1.9

Hz, 1H, H-2), 5.81 (dt, J = 10.1, 1.7 Hz, 1H, H-3), 5.64 (dt, J = 3.1, 1.7 Hz, 1H, H-1), 5.14

(dq, J = 9.1, 1.9 Hz, 1H, H-4), 4.28 (dq, J = 9.1, 6.3 Hz, 1H, H-5), 2.33 (s, 3H, CH₃), 2.11 (s,

3H, OCOCH₃), 1.27 (d, J = 6.3 Hz, 3H, CH₃); ¹³C NMR (50 MHz, CDCl₃) δ 170.4 (CH₃-CO-

O-), 137.5 (C-4’), 132.0 (C-2’), 131.6 (C-1’), 129.7 (C-3’), 128.6, 127.9 (C-2, 3), 84.0 (C-1),

70.7 (C-4), 65.3 (C-5), 21.1 (2C, CH₃, OCOCH₃), 18.0 (CH₃); Anal. Calcd for C₁₅H₁₈O₃S: C,

64.72; H, 6.52; O, 17.24; S, 11.52%. Found: C, 64.81; H, 6.50; S, 11.57%.

4.3.27 p-Tolyl 4-O-acetyl-1-thio-2,4,6-tridideoxy-β-L-erythro-hex-2-enopyranoside (β-

5g).

¹H NMR (200 MHz, CDCl₃) δ 7.45 – 7.37 (m, AA’MM’, 2H, H-2’), 7.16 – 7.08 (m,

AA’MM’, 2H, H-3’), 5.90 (dt, J = 10.2, 1.7 Hz, 1H, H-2), 5.74 (dt, J = 10.2, 2.2 Hz, 1H, H-

3), 5.53 (ddd, J = 2.5, 2.2, 1.7 Hz, 1H, H-1), 4.99 (dddd, J = 7.7, 2.5, 2.2, 1.7 Hz, 1H, H-4),

3.73 (dq, J = 7.7, 6.3 Hz, 1H, H-5), 2.33 (s, 3H, CH₃), 2.05 (s, 3H, OCOCH₃), 1.32 (d, J = 6.3

Hz, 3H, CH₃).

4.3.28

p-tert-Butylphenyl

4-O-acetyl-1-thio-2,4,6-tridideoxy-α-L-erythro-hex-2-

enopyranoside (α-5h).

Colourless oil; IR (neat, ν, cm^-1): 2963, 2904, 2870, 1741, 1489, 1372, 1231, 1090, 1061,

1

1039, 916, 783; H NMR (200 MHz, CDCl₃) δ 7.49 – 7.42 (m, AA’MM’, 2H, H-2’), 7.37 –

7.29 (m, AA’MM’, 2H, H-3’), 6.02 (ddd, J = 10.1, 3.1, 1.9 Hz, 1H, H-2), 5.81 (dt, J = 10.1,

1.7 Hz, 1H, H-3), 5.67 (dt, J = 3.1, 1.6 Hz, 1H, H-1), 5.15 (dq, J = 9.1, 1.9 Hz, 1H, H-4), 4.29

(dq, J = 9.1, 6.3 Hz, 1H, H-5), 2.11 (s, 3H, OCOCH₃), 1.31 (s, 9H, 3 × CH₃, C(CH₃)₃), 1.28

(d, J = 6.3 Hz, 3H, CH₃); ¹³C NMR (50 MHz, CDCl₃) δ 170.4 (CH₃-CO-O-), 150.6 (C-4’),

131.8 (C-1’), 131.5 (C-2’), 128.7, 127.9 (C-2, 3), 126.0 (C-3’), 83.9 (C-1), 70.7 (C-4), 65.4

(C-5), 34.5 (C(CH₃)₃), 31.2 (C(CH₃)₃), 21.1 (OCOCH₃), 18.0 (CH₃); Anal. Calcd for

C₁₈H₂₄O₃S: C, 67.47; H, 7.55; O, 14.98; S, 10.01%. Found: C, 67.41; H, 7.48; S, 9.93%.

4.3.29

p-tert-Butylphenyl

4-O-acetyl-1-thio-2,4,6-tridideoxy-β-L-erythro-hex-2-

enopyranoside (β-5h).

ACCEPTED MANUSCRIPT

¹H NMR (200 MHz, CDCl₃) δ 7.49 – 7.42 (m, AA’MM’, 2H, H-2’), 7.39 – 7.29 m,

AA’MM’, 2H, H-3’), 5.93 (dt, J = 10.2, 1.7 Hz, 1H, H-2), 5.77 (dt, J = 10.2, 2.3 Hz, 1H, H-

3), 5.56 (ddd, J = 2.5, 2.3, 1.7 Hz, 1H, H-1), 5.02 (dddd, J = 7.6, 2.5, 2.3, 1.7 Hz, 1H, H-4),

3.75 (dq, J = 7.6, 6.4 Hz, 1H, H-5), 2.06 (s, 3H, OCOCH₃), 1.34 (d, J = 6.4 Hz, 3H, CH₃),

1.28 (s, 9H, 3 × CH₃, C(CH₃)₃).

4.3.30

o-Fluorophenyl

4-O-acetyl-1-thio-2,4,6-tridideoxy-α-L-erythro-hex-2-

enopyranoside (α-5i).

Whitish microcrystalline solid; mp. 74 °C; IR (KBr, ν, cm^-1): 2978, 2933, 2893, 1734, 1571,

1474, 1383, 1238, 1093, 1042, 919, 779. 751; ¹H NMR (200 MHz, CDCl₃) δ 7.59 (td, J = 7.8,

2.0 Hz, 1H, H-5’), 7.36 – 7.23 (m, 1H, H-4’), 7.16 – 7.03 (m, 2H, H-3’, H-6’), 6.05 (ddd, J =

10.1, 3.0, 1.9 Hz, 1H, H-2), 5.86 (dt, J = 10.1, 1.6 Hz, 1H, H-3), 5.72 (dt, J = 3.0, 1.6 Hz, 1H,

H-1), 5.15 (dq, J = 9.1, 1.9 Hz, 1H, H-4), 4.31 (dq, J = 9.1, 6.2 Hz, 1H, H-5), 2.12 (s, 3H,

OCOCH₃), 1.24 (d, J = 6.2 Hz, 3H, CH₃); ¹³C NMR (50 MHz, CDCl₃) δ 170.4 (CH₃-CO-O-),

161.9 (d, ¹J_H-F= 245.9 Hz, C-2’), 134.7 (d, ⁴J_H-F= 1.1 Hz, C-5’), 129.8 (d, ³J_H-F= 8.0 Hz, C-

3

2

6’), 128.6, 128.2 (C-2, 3), 124.6 (d, J_H-F= 3.8 Hz, C-4’), 121.7 (d, J_H-F= 18.1 Hz, C-1’),

2

4

115.7 (d, J_H-F= 23.0 Hz, C-3’), 82.9 (d, J_H-F= 1.6 Hz, C-1), 70.6 (C-4), 65.6 (C-5), 21.0

(OCOCH₃), 17.8 (CH₃); Anal. Calcd for C₁₄H₁₅FO₃S: C, 59.56; H, 5.36; F, 6.73; O, 17.00; S,

11.36%. Found: C, 59.48; H, 5.43; S, 11.41%.

4.3.31

o-Fluorophenyl

4-O-acetyl-1-thio-2,4,6-tridideoxy-β-L-erythro-hex-2-

enopyranoside (β-5i).

¹H NMR (200 MHz, CDCl₃) δ 7.67 – 7.57 (m, 1H, H-5’), 7.36 – 7.27 (m, 1H, H-4’), 7.16 –

7.02 (m, 2H, H-3’, 6’), 5.97 (dt, J = 10.2, 1.7 Hz, 1H, H-2), 5.78 (dt, J = 10.2, 2.3 Hz, 1H, H-

3), 5.62 (ddd, J = 2.3, 2.0, 1.7 Hz, 1H, H-1), 4.92 (dddd, J = 7.4, 2.3, 2.0, 1.7 Hz, 1H, H-4),

3.76 (dq, J = 7.4, 6.4 Hz, 1H, H-5), 2.06 (s, 3H, OCOCH₃), 1.32 (d, J = 6.4 Hz, 3H, CH₃).

4.3.32

m-Fluorophenyl

4-O-acetyl-1-thio-2,4,6-tridideoxy-α-L-erythro-hex-2-

enopyranoside (α-5j).

Yellowish oil; IR (neat, ν, cm^-1): 3069, 2980, 2935, 2891, 1740, 1599, 1578, 1474, 1372,

1

1230, 1091, 1059, 1039, 879, 781; H NMR (200 MHz, CDCl₃) δ 7.34 – 7.19 (m, 3H, Ar),

7.03 – 6.88 (m, 1H, Ar), 6.01 (ddd, J = 10.0, 2.9, 1.7 Hz, 1H, H-2), 5.85 (dt, J = 10.1, 1.7 Hz,

1H, H-3), 5.75 (dt, J = 3.1, 2.1 Hz, 1H, H-1), 5.16 (dq, J = 9.1, 1.9 Hz, 1H, H-4), 4.23 (dq, J

= 9.1, 6.2 Hz, 1H, H-5), 2.11 (s, 3H, OCOCH₃), 1.28 (d, J = 6.2 Hz, 3H, CH₃); ¹³C NMR (50

1

3

MHz, CDCl₃) δ 170.4 (CH₃-CO-O-), 162.7 (d, J_H-F= 248.4 Hz, C-3’), 137.9 (d, J_H-F= 7.9

3

4

Hz, C-1’), 130.1 (d, J_H-F= 8.5 Hz, C-5’), 128.6, 128.1 (C-2, 3), 126.3 (d, J_H-F= 3.0 Hz, C-

6’), 117.6 (d, ²J_H-F= 22.8 Hz, C-2’), 114.1 (d, J_H-F= 21.2 Hz, C-4’), 83.3 (C-1), 70.6 (C-4),

2

65.7 (C-5), 21.0 (OCOCH₃), 18.0 (CH₃); Anal. Calcd for C₁₄H₁₅FO₃S: C, 59.56; H, 5.36; F,

6.73; O, 17.00; S, 11.36%. Found: C, 59.64; H, 5.32; S, 11.43%.

4.3.33

m-Fluorophenyl

4-O-acetyl-1-thio-2,4,6-tridideoxy-β-L-erythro-hex-2-

enopyranoside (β-5j).

ACCEPTED MANUSCRIPT

¹H NMR (400 MHz, CDCl₃) δ 7.30 – 7.24 (m, 3H, Ar), 7.01 – 6.94 (m, 1H, H-4’), 5.92 (dt, J

= 10.2, 1.7 Hz, 1H, H-2), 5.83 (dt, J = 10.2, 2.3 Hz, 1H, H-3), 5.65 (ddd, J = 2.5, 2.3, 1.7 Hz,

1H, H-1), 5.04 (dddd, J = 7.4, 2.5, 2.3, 1.7 Hz, 1H, H-4), 3.80 (dq, J = 7.4, 6.4 Hz, 1H, H-5),

2.08 (s, 3H, OCOCH₃), 1.35 (d, J = 6.4 Hz, 3H, CH₃); ¹³C NMR (101 MHz, CDCl₃) δ 170.4

(CH₃-CO-O-), 162.5 (d, ¹J_H-F= 248.4 Hz, C-3’), 135.7 (d, ³J_H-F= 8.0 Hz, C-1’), 130.0 (d, ³J_H-

4

2

_F= 8.4 Hz, C-5’), 129.4 (C-2), 128.3 (C-3), 127.4 (d, J_H-F= 3.0 Hz, C-6’), 118.6 (d, J_H-F

=

2

22.7 Hz, C-2’), 114.6 (d, J_H-F= 21.2 Hz, C-4’), 81.3 (C-1), 73.5 (C-5), 69.6 (C-4), 21.1

(OCOCH₃), 18.5 (CH₃).

4.3.34

p-Fluorophenyl

4-O-acetyl-1-thio-2,4,6-tridideoxy-α-L-erythro-hex-2-

enopyranoside (α-5k).

Colourless oil; IR (neat, ν, cm^-1): 3052, 2979, 2934, 2893, 1739, 1589, 1489, 1371, 1228,

1087, 1062, 1039, 830, 780; ¹H NMR (200 MHz, CDCl₃) δ 7.57 – 7.43 (m, AA’MM’, 2H, H-

2’), 7.10 – 6.94 (m, AA’MM’, 2H, H-3’), 6.01 (ddd, J = 10.1, 3.0, 1.9 Hz, 1H, H-2), 5.83 (dt,

J = 10.1, 1.6 Hz, 1H, H-3), 5.61 (dt, J = 3.0, 2.1 Hz, 1H, H-1), 5.15 (dq, J = 9.1, 1.9 Hz, 1H,

H-4), 4.27 (dq, J = 9.1, 6.3 Hz, 1H, H-5), 2.12 (s, 3H, OCOCH₃), 1.28 (d, J = 6.3 Hz, 3H,

13

1

CH₃); C NMR (50 MHz, CDCl₃) δ 170.4 (CH₃-CO-O-), 162.6 (d, J_H-F= 247.7 Hz, C-4’),

3

4

134.2 (d, J_H-F= 8.2 Hz, C-2’), 130.3 (d, J_H-F= 3.4 Hz, C-1’), 128.3, 128.2 (C-2, 3), 116.0

(d, J_H-F= 21.9 Hz, C-3’), 84.2 (C-1), 70.6 (C-4), 65.4 (C-5), 21.1 (OCOCH₃), 18.0 (CH₃);

2

Anal. Calcd for C₁₄H₁₅FO₃S: C, 59.56; H, 5.36; F, 6.73; O, 17.00; S, 11.36%. Found: C,

59.50; H, 5.33; S, 11.34%.

4.3.35

p-Fluorophenyl

4-O-acetyl-1-thio-2,4,6-tridideoxy-β-L-erythro-hex-2-

enopyranoside (β-5k).

¹H NMR (200 MHz, CDCl₃) δ 7.56 – 7.44 (m, 2H), 7.08 – 6.94 (m, 2H), 5.88 (dt, J = 10.2,

1.7 Hz, 1H, H-2), 5.75 (dt, J = 10.2, 2.2 Hz, 1H, H-3), 5.51 (ddd, J = 2.3, 2.2, 1.7 Hz, 1H, H-

1), 4.95 (dddd, J = 7.8, 2.3, 2.2, 1.7 Hz, 1H, H-4), 3.73 (dq, J = 7.8, 6.3 Hz, 1H, H-5), 2.06 (s,

3H, OCOCH₃), 1.31 (d, J = 6.3 Hz, 3H, CH₃).

4.3.36

o-Chlorophenyl

4-O-acetyl-1-thio-2,4,6-tridideoxy-α-L-erythro-hex-2-

enopyranoside (α-5l).

White microcrystalline solid; mp. 64 °C; IR (KBr, ν, cm^-1): 2978, 2962, 2931, 2851, 1738,

1

1454, 1375, 1237, 1090, 1035, 916, 786, 745. H NMR (200 MHz, CDCl₃) δ 7.71 – 7.65 (m,

ABMX, 1H, H-3’), 7.43 – 7.37 (m, ABMX, 1H, H-6’), 7.30 – 7.14 (m, ABMX, 2H, H-4’,

5’), 6.06 (ddd, J = 10.0, 3.1, 1.8 Hz, 1H, H-2), 5.88 (dt, J = 10.0, 1.7 Hz, 1H, H-3), 5.82 (dt, J

= 3.1, 1.8 Hz, 1H, H-1), 5.16 (dq, J = 9.0, 1.9 Hz, 1H, H-4), 4.27 (dq, J = 9.0, 6.2 Hz, 1H, H-

5), 2.12 (s, 3H, OCOCH₃), 1.25 (d, J = 6.2 Hz, 3H, CH₃); ¹³C NMR (50 MHz, CDCl₃) δ

170.4 (CH₃-CO-O-), 135.1 (C-2’), 134.7 (C-1’), 132.1 (C-6’), 132.0, 129.7, 128.8, 128.1,

127.3 (C-3’, 4’, 5’, 6’ and C-2, 3), 82.4 (C-1), 70.6 (C-4), 65.9 (C-5), 21.0 (OCOCH₃), 18.0

(CH₃); Anal. Calcd for C₁₄H₁₅ClO₃S: C, 56.28; H, 5.06; Cl, 11.87; O, 16.06; S, 10.73%.

Found: C, 56.19; H, 4.96; S, 10.63%.

ACCEPTED MANUSCRIPT

4.3.37

m-Chlorophenyl

4-O-acetyl-1-thio-2,4,6-tridideoxy-α-L-erythro-hex-2-

enopyranoside (α-5m).

Colourless viscous oil; IR (neat, ν, cm^-1): 3057, 2980, 2934, 2891, 1740, 1576, 1462, 1372,

1

1230, 1090, 1062, 1038, 772; H NMR (200 MHz, CDCl₃) δ 7.53 – 7.50 (m, 1H, H-2’), 7.44

– 7.34 (m, 1H, Ar), 7.28 – 7.21 (m, 2H, Ar), 6.01 (ddd, J = 10.1, 3.0, 1.8 Hz, 1H, H-2), 5.85

(dt, J = 10.1, 1.6 Hz, 1H, H-3), 5.74 (dt, J = 3.0, 1.7 Hz, 1H, H-1), 5.16 (dq, J = 9.1, 1.9 Hz,

1H, H-4), 4.23 (dq, J = 9.1, 6.2 Hz, 1H, H-5), 2.12 (s, 3H, OCOCH₃), 1.29 (d, J = 6.2 Hz, 3H,

CH₃); ¹³C NMR (50 MHz, CDCl₃) δ 170.4 (CH₃-CO-O-), 137.5 (C-3’), 134.6 (C-1’), 130.7,

129.9, 129.0, 128.6, 128.1, 127.4 (C-2’, 4’, 5’, 6’ and C-2, 3), 83.4 (C-1), 70.6 (C-4), 65.7 (C-

5), 21.0 (OCOCH₃), 18.0 (CH₃); Anal. Calcd for C₁₄H₁₅ClO₃S: C, 56.28; H, 5.06; Cl, 11.87;

O, 16.06; S, 10.73%. Found: C, 56.27; H, 5.13; S, 10.79%.

4.3.38

m-Chlorophenyl

4-O-acetyl-1-thio-2,4,6-tridideoxy-β-L-erythro-hex-2-

enopyranoside (β-5m).

¹H NMR (400 MHz, CDCl₃) δ 7.56 – 7.51 (m, 1H, H-2’), 7.43 – 7.37 (m, 1H, Ar), 7.28 –

7.20 (m, 2H, Ar), 5.92 (dt, J = 10.2, 1.7 Hz, 1H, H-2), 5.83 (dt, J = 10.2, 2.3 Hz, 1H, H-3),

5.63 (ddd, J = 2.4, 2.3, 1.7 Hz, 1H, H-1), 5.02 (dddd, J = 7.4, 2.4, 2.3, 1.7 Hz, 1H, H-4), 3.80

(dq, J = 7.4, 6.4 Hz, 1H, H-5), 2.08 (s, 3H, OCOCH₃), 1.35 (d, J = 6.4 Hz, 3H, CH₃); ¹³C

NMR (101 MHz, CDCl₃) δ 170.3 (CH₃-CO-O-), 135.1 (C-3’), 133.5 (C-1’), 131.6 (C-2’),

130.0 (C-Ar), 129.8 (C-Ar), 129.4 (C-2), 128.2 (C-3), 127.8 (C-Ar), 81.3 (C-1), 73.5 (C-5),

69.5 (C-4), 21.1 (OCOCH₃), 18.5 (CH₃).

4.3.39

p-Chlorophenyl

4-O-acetyl-1-thio-2,4,6-tridideoxy-α-L-erythro-hex-2-

enopyranoside (α-5n).

White microcrystalline solid; mp. 78 °C; IR (KBr, ν, cm^-1): 2982, 2969, 2931, 2874, 1732,

1479, 1371, 1230, 1092, 1072, 1043, 815, 782. ¹H NMR (400 MHz, CDCl₃) δ 7.47 – 7.42 (m,

AA’MM’, 2H, H-2’), 7.30 – 7.26 (m, AA’MM’, 2H, H-3’), 6.00 (ddd, J = 10.1, 3.1, 1.9 Hz,

1H, H-2), 5.84 (dt, J = 10.1, 1.7 Hz, 1H, H-3), 5.67 (dt, J = 3.1, 1.7 Hz, 1H, H-1), 5.15 (dq, J

= 9.1, 2.0 Hz, 1H, H-4), 4.24 (dq, J = 9.1, 6.3 Hz, 1H, H-5), 2.11 (s, 3H, OCOCH₃), 1.27 (d, J

= 6.3 Hz, 3H, CH₃); ¹³C NMR (101 MHz, CDCl₃) δ 170.5 (CH₃-CO-O-), 133.9 (C-4’), 133.6

(C-1’), 132.7 (C-2’), 129.1 (C-3’), 128.4 (C-3), 128.2 (C-2), 83.7 (C-1), 70.6 (C-4), 65.6 (C-

5), 21.1 (OCOCH₃), 18.0 (CH₃); Anal. Calcd for C₁₄H₁₅ClO₃S: C, 56.28; H, 5.06; Cl, 11.87;

O, 16.06; S, 10.73%. Found: C, 56.21; H, 5.11; S, 10.68%.

4.3.40

p-Chlorophenyl

4-O-acetyl-1-thio-2,4,6-tridideoxy-β-L-erythro-hex-2-

enopyranoside (β-5n).

¹H NMR (400 MHz, CDCl₃) δ 7.49 – 7.40 (m, AA’MM’, 2H, H-2’), 7.32 – 7.23 (m,

AA’MM’, 2H, H-3’), 5.89 (dt, J = 10.2, 1.7 Hz, 1H, H-2), 5.79 (dt, J = 10.2, 2.3 Hz, 1H, H-

3), 5.56 (ddd, J = 2.5, 2.3, 1.7 Hz, 1H, H-1), 4.99 (dddd, J = 7.6, 2.5, 2.3, 1.7 Hz, 1H, H-4),

3.75 (dq, J = 7.6, 6.3 Hz, 1H, H-5), 2.06 (s, 3H, OCOCH₃), 1.32 (d, J = 6.3 Hz, 3H, CH₃).

ACCEPTED MANUSCRIPT

4.4. X-ray crystallographic analysis of 4m and 4n

Single-crystal X-ray diffraction data for 4m and 4n were collected at room temperature on

an Agilent Gemini S diffractometer equipped with Mo Kα radiation (λ = 0.71073 Å). Data

reduction and empirical absorption corrections were performed with CrysAlisPro.⁴⁸Crystal

structure was solved by direct methods, using SIR2002⁴⁹and refined using SHELXL-97

program⁵⁰by full-matrix least-squares on F².

In both crystal structures all H-atoms bound with aromatic C-atoms as well as H-atoms

attached to the C2 and C3 were placed geometrically and refined using a riding model with

C−H = 0.93 Å and U_iso(H) = 1.2 U_eq(C). The hydrogen atoms from methine, methylene and

methyl groups were placed at geometrically idealized positions with C–H distances fixed to

0.98, 0.97 and 0.96 Å respectively. Their isotropic displacement parameters were set equal to

1.2U_eqand 1.5U_eqof the parent C atoms.

Selected crystallographic data for 4m: C₁₆H₁₇ClO₆S, M = 356.81, colorless prismatic

crystals, D_calc= 1.387 Mg/m³, triclinic crystal system, space group P1, Z = 1, final R indicates

R₁/wR₂(I≥2σ_I) = 0.0456/0.1027 (210 parameters and 3810 independent reflections), GOF =

1.055.Selected crystallographic data for 4n: C₁₆H₁₇ClO₆S, M = 356.81, colorless prismatic

crystals, D_calc= 1.360 Mg/m³, monoclinic crystal system, space group P2₁, Z = 2, final R

indicates R₁/wR₂(I≥2σ_I) = 0.0492/0.0943 (210 parameters and 3046 independent reflections),

GOF = 1.049.

Acknowledgments

Financial support from the Ministry of Education, Science and Technological Development

of the Republic of Serbia (Grant No. 172034) is gratefully acknowledged.

Supplementary Material

Comparative tables of the assigned ¹H and ¹³C NMR data for 4a-n and 5a-n.

Crystallographic data for the structural analysis have been deposited with the Cambridge

Crystallographic Data Centre, CCDC Nos. 1012695 and 1012696 for compounds 4m and 4n

respectively.

These

data

can

be

obtained

free

of

charge

via

www.ccdc.cam.ac.uk/data_request/cif.

References

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2nd ed; Elsevier: Amsterdam, 2009

ACCEPTED MANUSCRIPT

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Article Doi

Ferrier rearrangement promoted by an electrochemically generated zirconium catalyst

DOI: 10.1016/j.carres.2015.02.001

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Full text of DOI:10.1016/j.carres.2015.02.001

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