Regioselective benzylation of pentitols, tetritols, and some hexitols via their stannyl ether derivatives: Versatile synthesis of monobenzylalditols

This article was downloaded by: [UQ Library]

On: 05 November 2014, At: 00:54

Publisher: Taylor & Francis

Informa Ltd Registered in England and Wales Registered Number: 1072954 Registered office: Mortimer

House, 37-41 Mortimer Street, London W1T 3JH, UK

Journal of Carbohydrate Chemistry

Publication details, including instructions for authors and subscription information:

http://ww w .tandfonline.com/loi/lcar20

REGIOSELECTIVE BENZYLATION OF PENTITOLS,

TETRITOLS, AND SOME HEXITOLS VIA THEIR STANNYL

ETHER DERIVATIVES: VERSATILE SYNTHESIS OF

MONOBENZYLALDITOLS

Sami Halila ^a, Mohammed Benazza ^b& Gilles Demailly ^a

^aUniversité de Picardie Jules Verne , Laboratoire de Chimie Organique, 33 rue Saint-

Leu, Amiens, F-80039, France

^bUniversité de Picardie Jules Verne , Laboratoire de Chimie Organique, 33 rue Saint-

Leu, Amiens, F-80039, France

Published online: 19 Aug 2006.

To cite this article: Sami Halila , Mohammed Benazza & Gilles Demailly (2001) REGIOSELECTIVE BENZYLATION OF

PENTITOLS, TETRITOLS, AND SOME HEXITOLS VIA THEIR STANNYL ETHER DERIVATIVES: VERSATILE SYNTHESIS OF

MONOBENZYLALDITOLS, Journal of Carbohydrate Chemistry, 20:6, 467-483, DOI: 10.1081/CAR-100106930

To link to this article: http://dx.doi.org/10.1081/CAR-100106930

PLEASE SCROLL DOWN FOR ARTICLE

Taylor & Francis makes every effort to ensure the accuracy of all the information (the “Content”) contained

in the publications on our platform. However, Taylor & Francis, our agents, and our licensors make no

representations or warranties whatsoever as to the accuracy, completeness, or suitability for any purpose of

the Content. Any opinions and views expressed in this publication are the opinions and views of the authors,

and are not the views of or endorsed by Taylor & Francis. The accuracy of the Content should not be relied

upon and should be independently verified with primary sources of information. Taylor and Francis shall

not be liable for any losses, actions, claims, proceedings, demands, costs, expenses, damages, and other

liabilities whatsoever or howsoever caused arising directly or indirectly in connection with, in relation to or

arising out of the use of the Content.

This article may be used for research, teaching, and private study purposes. Any substantial or systematic

reproduction, redistribution, reselling, loan, sub-licensing, systematic supply, or distribution in any

form to anyone is expressly forbidden. Terms & Conditions of access and use can be found at http://

www.tandfonline.com/page/terms-and-conditions

J. CARBOHYDRATE CHEMISTRY, 20(6), 467–483 (2001)

REGIOSELECTIVE BENZYLATION OF

PENTITOLS, TETRITOLS, AND SOME HEXITOLS

VIA THEIR STANNYL ETHER DERIVATIVES:

VERSATILE SYNTHESIS OF

MONOBENZYLALDITOLS

Sami Halila, Mohammed Benazza,* and Gilles Demailly

Laboratoire de Chimie Organique, Université de Picardie Jules Verne,

33 rue Saint-Leu F-80039 Amiens, France

ABSTRACT

The xylitol, ribitol and D-arabinitol were transformed into their tributylstannyl

ether derivatives by reaction with bis-tributyltin oxide [(nBu₃Sn)₂O I] and

azeotropic removal of water. Subsequent benzyl etherification, using BnBr

with solvent or under free solvent conditions, led regioselectively to primary

mono-O-benzylalditol derivatives in satisfactory yields for a direct regioselec-

tive synthesis (ꢀ 52%). This etherification when applied to tetritols and some

hexitols exhibits similar behaviour. With pentitols, an analogous study carried

out with the n-dibutyltin oxide [nBu₂SnO (II)] as the activating reagent showed

contrasting results as regards regioselectivity.

INTRODUCTION

The regioselective etherification and esterification of unprotected polyols is

a useful transformation in organic synthesis.^1,2A range of conditions for the re-

gioselective introduction of a benzyl moiety has been described in the literature.^3–5

With alditols which contain more than three hydroxyl groups, the direct re-

gioselective etherification of the primary alcohol functions are drastically limited,

*Corresponding author. Fax ꢀ33(3)22827562; E-mail: mohammed.benazza@sc.u-picardie.fr

467

www.dekker.com

ORDER

REPRINTS

468

HALILA, BENAZZA, AND DEMAILLY

Scheme 1.

due to random etherification also occurring at the secondary hydroxyl goups. To

avoid this difficulty with xylitol, a prior acetal protection step enables one free pri-

mary hydroxyl group to be conserved,⁶and this can subsequently be esterified,

etherified or thioetherified.⁷

More recently, efficient direct regioselective monoalkylation of symmetric

l,n-alkanediols (n ꢁ 2 to 10) via their dibutylstannylene acetal derivatives (using

Table 1. Benzylation of Pentitols via Their

Conditions

BnBr

Entry

Substrate

Xylitol (1)

Tin-reagent

(eq.)

Salt(eq)

Solvent

1

2

3

4

5

6

7

8

9

(n-Bu₃Sn)₂O (I)

(2.5)

“

(1)

“

(2.5)

(1)

“

(4)

“

-

HCCl₃

without

“

Ribitol (5)

D-Arabinitol (9)

Xylitol (1)

“

HCCl₃

n-Bu₂SnO (II)

(2.5)

“

CsF(2)

-

NBu₄Br (2)

10

Ribitol (5)

-

11

12

13

14

“

(2.5)

“

(4)

“

-

“

D-Arabinitol (9)

(2)

(2.5)

(4)

“

(2.5)

^ppꢁ primaryꢂprimary; ^psꢁ primaryꢂsecondary; *With complex mixture; **peracetylated alditols

ORDER

REPRINTS

VERSATILE SYNTHESIS OF MONOBENZYLALDITOLS

469

nBu₂SnO (II) as the activating reagent) has been reported.^8aFor example, ribose

diethyl dithioacetal has been converted into its 5-O-alkyl ether in good yield (68%)

via the dibutylstannylene acetal.^8b

We have required some monobenzylated pentitols for use in recent thia and

aza heterocyclic synthesis,⁹the stannylene acetal complexes of pentitols being

used as intermediates. Unfortunately, the only targeted primary monobenzyl

derivative obtained was from xylitol.¹⁰

Herein, we report the regioselective primary mono benzylation of the penti-

tols, xylitol, ribitol and D-arabinitol, via their stannyl ether complexes (using

(Bu₃Sn)₂O (I) as activating reagent). Next, this reaction was applied to tetritols,

erythritol and D,L-threitol, and some hexitols, D-mannitol with C₂-symmetry, D-

glucitol and galactitol. The alditol stannyl ether derivatives were prepared by re-

fluxing a mixture of bis-(tributyltin) oxide and alditols in toluene with azeotropic

removal of the water formed.³

RESULTS AND DISCUSSION

The first regioselective pentitol O-benzylation attempt was carried out with

xylitol (1) (Scheme 1) and (nBu₃Sn)₂O (I) under the conditions reported in the

Table 1 (entry 1). The expected 2,3,4,5-tetra-O-acetyl-1-O-benzyl-DL-xylitol (3)

was obtained as the main product (45% yield) after acetylation and chromatogra-

Stannyl Ether or Stannylene Acetal Derivatives

Isolated yields (%)

Substrate

T(°C)

Time(h)

Mono-(%)

di-(%)

tri-(%)

(%)**

reflux

80

90

80

reflux

“

rt

reflux

rt

120

10

20

“

65

“

3

“

(45)

2^pp

(3)

(10)

(52)

(16)

(4)

-

4 (50)

(50)

(20)

(52)

(50)

(60)

(53)

(28)

(10)

(17)

“

(30)

(5)

7

11/12

3

6^pp

8

13

4

(23)

(36)

(33)

(9)

10^pp

2^pp

(5)

“

-

5

“

(23)

(52)

-

14^1,2,5

(8)

(17)

-

“

65

10

65

“

(0)

“

7

“

8

(85)

(47)

(15)

(16)

65

6^pp

(10)

mixture

15^{ps (1,4)}

“

50

65

“

40

65

“

(26)

(31)

(25)

(20)

6^pp

15^{ps (1,4)}

6^pp

15^{ps (1:4)}

10^pp

17^p,s;(4:5)

10^pp

17^p,s;(4:5)

(11) (20)

(8) (17)

(4) (13)

(0) (25)

“

16^(1:4:5)

“

(32)

(51)

(13)

11/12

“

(3)

13

(33)

ORDER

REPRINTS

470

HALILA, BENAZZA, AND DEMAILLY

phy on silica gel. The 1,5-di-O-benzylxylitol derivative 2 was isolated in only a

small amount (3%). The yield of monobenzylated derivative 3 reached 50% in a

short time using solvent free conditions (entry 2). Increasing both reaction temper-

ature (90 °C) and time (20 h) led to the 1,5-di-O-benzyl derivative 2 in good yield

(52%, entry 3).

With the solvent free conditions reported in entry 4, ribitol (5) and the organ-

otin reagent I gave the mono-O-benzylated and di-O-benzylated derivatives 7 and

6 in yields of 52 and 16%, respectively (Scheme 2). The monobenzylation of ribitol

was slower than that of xylitol (entry 2), as 20 h were needed to complete the re-

action. On the other hand, the attempt to favour the dibenzylated derivative 6 at a

higher temperature and a long time (90 °C, 20 h) led to a complex mixture.

The stannyl ether complex of D-arabinitol (9) was submitted to both solvent-

free conditions and using solvent. The solvent-free conditions appear to be drastic

since compound 9 led mainly to a mixture of unidentified benzylated by-products.

However, with chloroform as solvent, the D-arabinitol tin complex refluxed with

BnBr for 65 h (entry 5) led, after acetylation (Scheme 3), to an equimolar mixture

of regioisomeric 1-O-benzyl and 5-O-benzyl-D-arabinitol (or 1-O-benzyl-D-lyxi-

tol) derivatives 11 and 12 in 50% overall yield (ratio determined by ¹³C NMR spec-

troscopy). The further O-benzylation of the second terminal primary alcohol group

in the corresponding monoprotected tin complexes is slower. Only a 20% yield of

the 2,3,4-tri-O-acetyl-1,5-di-O-benzyl-D-arabinitol (10) was obtained after 5 days

in refluxing HCCl₃.

Compared with previous results obtained with the stannylene acetal interme-

diate (obtained with organotin oxide II as the activating reagent), xylitol appears

to follow the same behaviour. Both the primary-primary di-O-benzylated and the

primary mono-O-benzylated derivatives 2 and 3 were obtained mainly under con-

ditions shown in entries 6 to 8, respectively.¹⁰The use of only 1 equivalent of

nBu₂SnO favoured a selective formation of targeted mono-O-benzyl xylitol 3 in

Scheme 2.

ORDER

REPRINTS

VERSATILE SYNTHESIS OF MONOBENZYLALDITOLS

471

Scheme 3.

good yield (60%, entry 6); the benzylation of secondary hydroxyl groups was ex-

cluded. Furthermore, under the same conditions, but in the presence of added ce-

sium fluoride (2 equiv, entry 7), the benzylation occurred much faster (5 h instead

of 65 h for complete reaction) without heating and with approximately the same re-

giochemistry. This salt effect was previously reported by Naguashima et al.¹¹Sur-

prisingly, tetrabutylammonium bromide (entry 9), which was conveniently used

under nonpolar conditions, led to an unexpected decrease in reaction rate, and to a

complex mixture when DMF was used as the aprotic polar solvent. Finally, the

complete benzylation of both primary positions seems to depend on the organ-

otin/substrate ratio used. Thus, 2.5 equiv of II (entry 8) instead of 1 equiv led to

1,5-di-O-benzylated derivative in 52% yield.

It should be emphasized, that use of added salt or base to the xylitol stannyl

ether and benzyl bromide led to complex mixtures.

In comparison to xylitol, ribitol and D-arabinitol O-benzylation via the stan-

nylene acetal (obtained with organotin reagent II) led, in addition to normally

formed primary O-benzylated derivatives (6, 7, 10, 11 and 12), to some unexpected

primary-secondary di-O-benzylated by-products (15, 16 and 17). The amount of

secondary O-benzyl substitution seems to depend on the pentitol substrate; under

moderate conditions, unsymmetrical D-arabinitol (9) gave, after acetylation of the

crude product, a regioisomeric mixture of primary mono-O-benzyl derivatives 11

and 12 in 25% overall yield (one of them is in twofold majority) plus 1,2,3-tri-O-

acetyl-4,5-di-O-benzyl-D-arabinitol (17) in a yield of 13% (entry 13). Only traces

of primary di-O-benzyl derivative 10 (4%) and 1,4,5-tri-O-benzyl derivative 16

(3%) were isolated. With a large excess of BnBr (4 equiv, entry 14) the obtained

yields of 4,5-di-O-benzylated and 1,4,5-tri-O-benzylated derivatives 17 and 16

were, respectively, 25 and 33%. Only a small amount of substrate remained (13%).

ORDER

REPRINTS

472

HALILA, BENAZZA, AND DEMAILLY

This result suggests that D-arabinitol was first transformed primarily into a mixture

of regioisomeric mono-O-benzyl derivatives, 5-O-benzyl-D-arabinitol as major

product and 1-O-benzyl-D-arabinitol as minor product, the former then undergoing

regioselective O-benzylation of the secondary hydroxyl group at C-4. Further

etherification took place subsequently at the primary C-1 alcohol.

It is of interest to note that a different regioselectivity behaviour was adopted

by the stannylene acetal complex of ribitol (obtained with organotin complex II).

While the vicinal 4,5-di-O-benzyl derivative 17 was formed from D-arabinitol, un-

der the same conditions ribitol stannylene acetal as intermediate led to primary-

secondary 1,4-di-O-benzyl derivative 15 (entry 11 to 13). No tri-O-benzylated

derivative was detected.

In compound 17, the secondary and the primary benzyl groups at C-4 and C-

5 positions, respectively, were located by NMR spectroscopy (Table 2, 3 and 4).

1

The H NMR spectrum showed a large coupling constant of 6.9 Hz for anti-3,4-

methine and a weak coupling constant of 3.7 Hz for syn-2,3-methine. These values

Table 2. ¹H Chemical Shifts (ꢃ) for Peracetylated Mono,

H-1

H-1ꢄ

H-2

H-3

H-4

H-4ꢄ

H-5

2 (xylo)

3.49(dd) 3.55(dd) 5.22(dd) 5.57(t)

5.22 (dd)

3.49 (dd)

3 “

4 “

2.40(dd) 2.36(dd) 5.13(m)

3.80(dd

5.44(dd) 5.22(m)

5.10(dd)

4.24(dd)

3.80(dd)

4.13(dd) 5.10(dd) 5.20(t)

6 (ribo)

3.52(dd) 3.62(dd) 5.27(dd) 5.38(t)

5.27(dd)

3.52(dd)

7 “

8 “

3.48(dd) 3.58(dd) 5.25(m)

4.40(dd) 4.63(dd) 5.66(dd) 5.80(t)

5.33(dd) 5.20(m)

4.09(dd)

4.40(dd)

5.66(dd)

10 (arabino) 3.53(dd) 3.55(dd) 5.46(m)

5.43(dd) 5.16(m)

5.88(dd) 5.57(m)

3.48(dd)

4.41(dd)

13 “

4.29(dd) 4.59(dd) 5.77(m)

14 (xylo)

15 (ribo)

3.61(d)

3.77(m)

5.50(dd) 5.34(m)

3.38(dd)

4.10(dd)

3.59(dd)

3.50(dd)

3.55(dd) 3.62(dd) 5.40(m

5.40(m)

5.20(m)

16 (arabino) 3.55(dd) 3.59(dd) 5.48(m)

17 “

19 (threo)

20 “

21 “

25 (erythro)

26 “

27 “

31(manno)

32 “

35

5.43(dd) 3.73(m)

5.34(dd) 3.70(m)

4.00(dd) 4.23(dd) 5.50(m)

3.42(dd) 3.44(dd) 5.13(m)

3.55(m)

3.70(m)

3.50(dd) 3.55(dd) 5.18(m)

3.51(dd) 3.56(dd) 5.24(m)

3.68(dd) 3.75(dd) 5.42(m)

3.43(dd) 3.52(dd) 5.07(m)

3.43(dd) 3.52(dd) 5.05(m)

3.41(dd) 3.45(dd) 5.06(m)

4.36(dd) 4.55(dd) 5.50(m)

5.28(m)

3.83(m)

4.00(m)

5.25(m)

3.70(m)

3.99(m)

5.46(d)

5.46(s)

3.92(dd)

4.02(dd)

3.7(m)

4.15(dd)

4.18(dd)

3.80(dd)

5.46(d)

5.41(s)

4.21(dd)

4.15(dd)

3.70(m)

4.27(dd)

4.30(dd)

3.83(dd)

3.55(m)

3,70(m)

5.14(m)

5.40(m)

5.07(m)

5.03(m)

5.19(m)

5.50(dd)

5.17(t)

5.41(dd) 5.59(dd)

38

5.88(d)

5.33(s)

5.88(d)

5.33(s)

40 (galacto)

41

3.38(d)

5.17(t)

5.21(m)

5.35(dd) 5.30(dd)

5.19(m)

ORDER

REPRINTS

VERSATILE SYNTHESIS OF MONOBENZYLALDITOLS

473

are consistent with the planar zig-zag conformation previously proposed for per-

acetylated¹²and 1,5-dihalogenated D-arabinitol derivatives.¹³Subsequently, the

vicinal 4,5-di-O-benzyl positions were indicated by ¹³C NMR shift correlation.

The same study was carried out for the tribenzylated and dibenzylated derivatives

16 and 10; these produced the same J_3,4-J_2,3anti-syn methine sequence.

The synthesis in satisfactory yields of primary monobenzylated pentitols via

their stannyl ether derivatives, allowed us to expand this reaction to tetritols and

some hexitols (Tables 5 and 6). Thus, we showed that with tetritol stannyl ether

complexes, the monobenzylation occurred in good yields using solvent-free con-

ditions. Furthermore, we observed that the rate of primary regioselective O-benzy-

lation of D,L-threitol (18) was faster than of erythritol (24). In fact, while only 5 h

were needed to obtain the 1-O-benzyl-D,L-threitol derivative 19 in 54% yield (en-

try 1, Table 6), 20 h were required to obtain 1-O-benzyl-D,L-erythritol derivative

25 in 50% yield (entry 3). On the other hand, in both cases, 1,3-di-O-benzylated

derivatives were isolated as by-product in minor yields. With erythritol, the yield

Di, and Tri-O-benzylated Alditol Derivatives (in CDCl₃)

H-5ꢄ

H-6

H-6ꢄ

CH₃

CH₂(Bn)

Ph(Bn)

3.55 (dd)

2.02(s) (6H);

1.99(s, 3H)

2; 1.98; 1.93

1.84(s, 6H);

1.89(s, 3H)

1.92(s, 6H);

1.99(s, 3H)

2.03; 1.98; 1.95

2(s, 6H);

4.45(s)(4H)

7.29(m)(10H)

3.92(dd)

4.13(dd)

3.62(dd)

4.46(s, 4H)

7.29(m, 10H)

4.29(dd)

4.63(dd)

4.44(s, 2H)

-

7.24 (m, 5H)

-

2.1(s,9H)

3.60(dd)

4.54(dd)

2.05; 1.98; 1.92

2.07(m, 12H)

4.45(m,4H)

7.20(m, 10H)

3.49(dd)

4.30(dd)

3.61(dd)

3.62(dd)

2.10(s, 6H)

2.02; 2; 1.96

2; 1.96

2.01; 1.98; 1.91

1.89; 1.91; 1.95

1.29; 1.98

4.49(s, 6H)

4.38(s, 4H)

4.48(m, 6H)

4.55(m, 4H)

4.36(dd, 2H)

4.47(d); 4.40(d)

4.81(dd); 4.68(dd)

4.45(dd)

4.50(dd); 4.12(dd)

4.74(dd); 4.78(dd)

4.47(d); 4.40(d)

4.47(dd)

7.30(m, 15H)

7.24(m, 5H)

7.27(m, 15H)

7.26(m, 10H)

7.19(m, 5H)

7.25(m, 10H)

7.3(m)

7.24(m)

7.25(m)

7.39(m)

7.24(m)

2.08

1.94; 1.96; 2.00

1.98(s, 6H)

2.07

2.10(m, 12H)

2.03(m, 15H)

1.98(m, 12H)

2.13; 2.11; 2.03

2.01; 1.96

3.43(dd)

4.01(dd)

3.58(dd)

4.36(dd)

3.38(d)

3.52(dd)

4.17(dd)

3.62(dd)

4.55(dd)

3.38(d)

7.25(m)

7.23(m)

4.43(m, 4H)

4.34(dd); 4.42(dd)

7.23(m)

7.24(m)

3.77(dd)

4.20(dd)

2.01; 1.94

ORDER

REPRINTS

474

HALILA, BENAZZA, AND DEMAILLY

Table 3. Coupling Constants (Hz) for Peracetylated Mono, Di, and Tri-O-benzylated Alditol

Derivatives (in CDCl₃)

Coupling constants (Hz)

Compd.

J_1,1ꢄJ_1,2J_1ꢄ,2J_2,3J_3,4J_3,4ꢄJ_4,4ꢄJ_4,5J_4,5ꢄJ_5,5ꢄJ_5,6J_5,6ꢄJ_6,6ꢄ

2(xylo)

3 “

4 “

10.6 4.6 5.2 5.4 5.4

10.7 4.8 4.7 5.4 5.4

4.6 5.2

4.6 6.2

6.2 4.3

10.6

11.9

12

6.2 4.3 5.3 5.3

6(ribo)

7 “

8 “

12.6 6.2 3.7 5.4 5.4

10.7 5.8 4.0 5.2 5.2

12.3 3.3 6.1 5.7 5.7

6.2 3.7

6.4 3.0

3.3 6.1

12.6

12.2

12.3

10(arabino) 10.3 7.3 3.8 3.1 7.9

7.4 5.7

5.1 2.6

10.8

12.4

13 “

11.9 6.9 4.6 2.3 8.6

14(xylo)

15(ribo)

-

5.0 5.0 6.2 4.4

5.2 4.0

5.3 3.4

6.0 4.2

5.0 4.2

10.8

12.2

10.3

10.5 5.7 3.2

-

16(arabino) 10.7 7.5 3.5 4.4 5.8

17 “

19(threo)

20 “

21 “

11.8 6.3 5.0 3.7 6.9

4.0 4.0 0.0 5.3 3.1 12.1

10.5 5.9 3.9 0.0 6.1 4.5 11.6

10.2 5.7 4.4 5.0 10.4

-

25(erythro) 10.7 5.4 4.3 5.8 6.2

3

12.5

26 “

27 “

10.8 5.5 4.3 5.6 6.6 2.7 12.7

10.7 5.4 4.3 5.8 5.7 4.2 11.0

31(manno) 10.8 5.4 3.9 8.3

-

8.3

8.8

5.4 3.9 10.8

5.2 2.5 12.5

32 “

10.7 5.1 3.8 9.3 2.0

35(glu)

38 “

8.6 5.6 3.1 4.2 6.1

4.5

5.9

5.2 2.5 12.5

5.1 2.8 12.4

12.4 5.1 2.8 5.9

-

40(galacto)

41 “

-

6

5

6

5

0

9.9

-

0

10.5

6

-

8.1 4.2 11.1

of 1,3 primary-secondary di-O-benzyl derivative 26 reached 50% using a large ex-

cess of BnBr (entry 4). Furthermore, with both D,L-threitol and erythritol, simulta-

neous use of a large excess of BnBr and a long reaction time (20 h) led mainly to

the tribenzylated derivatives 21 (62%, entry 2) and 27 (60%, entry 5), respectively.

Finally the more complex hexitols namely, D-mannitol (30), D-glucitol (34)

and galactitol (39), transformed to their stannyl ether derivatives, led after benzy-

lation, to the corresponding monobenzyl ethers 32, 36/37 and 41 in reasonable

yields (45 to 48%) (entries 6 to 9, Table 6).

In conclusion, from a synthetic point of view, the most interesting result to

note in this work is the generalized regioselective benzylation (via the tributyl-

stannyl ether complex) at only one primary position of alditols, and often under

ORDER

REPRINTS

VERSATILE SYNTHESIS OF MONOBENZYLALDITOLS

475

solvent-free conditions. The monobenzylated derivatives were obtained in satis-

factory yields for a direct regioselective synthesis (47 to 54%). Current work is di-

rected towards studying the reactivity of alditols organotin complexes towards

other electrophiles.

EXPERIMENTAL

General methods. Melting points were determined with a Buchi 535 ap-

paratus and are uncorrected. ¹H and ¹³C NMR spectra were recorded in CDCl₃on

Bruker 300 WB spectrometer; chemical shifts are reported in ꢃ (ppm) relative to

Me₄Si. Coupling constants, assigned by double irradiation, are in Hz. All ¹³C NMR

signals were assigned though C,H-correlated spectra. TLC was performed on sil-

ica Gel 60 F₂₅₄230 mesh (E. Merck) with hexane-EtOAc as eluent, and zones were

detected by vanillin-H₂SO₄reagent. The silica gel used in column chromatography

was 35–70 m (Amicon). Mass spectroscopy analyses were performed by the “Ser-

vice d’Analyse de la Faculté de Pharmacie, Laboratoire de Chimie Thérapeutique

U.R.A. au CNRS, (Université de Reims Champagne Ardenne)”. Elemental analy-

ses were performed by the “Service de Microanalyse du CNRS” (Laboratoire de

Bioorganique, Université de Reims Champagne Ardenne”.

General procedure for O-benzylation via the stannyl ether complex.

The alditol (0.2 g) was allowed to react with the (nBu₃Sn)₂O (I) in refluxing

toluene (20 mL). After azeotropic removal of water over 5 h the solvent was evap-

orated under vacuum. The syrup obtained was dried and submitted to O-benzyla-

tion under conditions reported in Tables 1 and 2. The crude product was dried and

peracetylated with excess of acetic anhydride in pyridine at room temperature. Af-

ter extraction following the usual procedure, the syrup obtained was treated with

aqueous KF¹⁴(20%) overnight. The organotin residue was filtered and the crude

product was chromatographed on silica gel with a mixture of hexane-ethyl acetate

as eluent. From the alditols studied, the following products were isolated in the re-

ported yields under optimal conditions of monobenzylated derivatives (see Tables

1 and 2).

From xylitol (1) (for conditions see entry 2, Table 1):

2,3,4-Tri-O-acetyl-1,5-di-O-benzylxylitol (2). Syrup; Yield 60 mg (10%);

R_f0.49 in 5:2 hexane-EtOAc; MS: m/z 459, M (C₂₅H₃₀O₈) 458.50;

Anal. Calcd for C₂₅H₃₀O₈: C, 65.49; H, 6.60; O, 27.92. Found: C, 65.77; H,

6.68.

2,3,4,5-Tetra-O-acetyl-1-O-benzyl-D,L-xylitol (3). Syrup; Yield 270 mg

(50%); R_f0.37 in 5:2 hexane-EtOAc; MS: m/z 411 [M ꢀ 1], M (C₂₀H₂₆O₉) 410.42.

Anal. Calcd for C₂₀H₂₆O₉: C, 58.53; H, 6.39; O, 35.09. Found: C, 58.90; H,

6.42.

The di-O-benzyl derivative 2 was obtained in major part (50%) in conditions

reported in entry 4.

ORDER

REPRINTS

476

HALILA, BENAZZA, AND DEMAILLY

Table 4. ¹³C Chemical Shifts (ꢃ) for Peracetylated Mono,

Compd

C-1

C-2

C-3

C-4

C-5

C-6

CO(Ac)

2

3

68.1

67.7

70.5

69.3

69.9

70.3

70.5

69.3

68.1

61.8

169.4; 170.1

169.6; 169.8;

170; 170.2

168.5; 168.7;

169

169.4; 169.9;

170.6

169.3; 169.7;

169.8; 170.5

169.8; 169.5;

170.2

4

60.9

67.9

67.7

61.8

68.3

68.2

69.4

69.7

69.8

69.0

68.2

70.2

70.3

69.3

70.3

68.2

69.4

69.7

69.8

69.3

60.9

67.9

61.9

61.8

6

7

8

10

169.6; 169.8;

170; 170.2

169.51; 169.77;

170.34

11/ 12

67.90, 67.72,

62.02 or

61.62

68.71 68.18 68.71 67.90, 67.72,

62.02 or

61.62

13

14

15

16

17

62.9

68.2

76.2

70.7

70.2

69.2

70.0

69.4

71.2

71.8

70.5

70.0

69.4

68.7

71.1

73.9

76.0

75.6

61.9

62.5

68.2

61.2

68.7

69.0

170.4; 170.6;

170.7

170.1

69.7

66.9

64.4

62.7

169.5; 168.7;

168.3

169.9; 170.1

169.7; 169.9;

170.3

169.85; 169.74

170.29; 170.62

19

20

67.6

67.68

71.49 77.46 62.87

21

68.72

71.26 75.85 67.36

169.48

25

26

27

60.97

62.67

68.42

68.81 69.19 66.63

75.18 71.18 67.86

76.91 72.08 69.75

168.88; 169.59

169.04

169.5

29

68.39

68.32 68.56 68.56 68.32

68.5 68.9 68.9 68.5

68.39

169.68; 169.93

31

32

62.7

68.21

62.7

61.84

170.9; 170.4

169.65; 169.92;

170.53

68.49 68.04 67.56 67.84

33

67.64

68.99 69.75 70.48 68.99

67.92

169.77; 170.23

36/37

67.21 or 67.72

-

60.49 or 169.20

60.77

40

41

68.3

67.6

68.4

67.9

68.4

68.3

62.21

169.37; 168.82

170.24; 169.74

67.63 67.63 67.63 67.63

* In mixture with 12; ** In mixture with 11

ORDER

REPRINTS

VERSATILE SYNTHESIS OF MONOBENZYLALDITOLS

477

Di, and Tri-O-benzylated Alditol Derivatives (in CDCl₃)

Me(Ac)

CH₂(Bn)

73.2

Ph (Bn)

C-ipso

137.5

20.5; 20.7

20.5; 20.6;

20.7

128.3; 127.7

73.3

137.4

19.3; 19.4;

19.5

20.9; 20.7

-

128.3; 128; 127.7

128

-

73.1

137.6

137.5

20.6; 20.7;

20.9

20.2; 20.4

-

20.5; 20.9;

20.7

20.49

73.3

128.3; 127.7

128.30; 127.73

137.4

73.25

137.32

-

20.8; 20.9;

21

-

20.9; 20.8

73.5; 73.1;

72.5

69.6; 69.0

128.3; 127.9;

127.7

127.1; 126.8

137.9; 137.7

136.5; 136.2

137.9

19.7; 19.5

20.9; 20.7

20.6

73.4; 73.2;

72.4

73.5; 72.5

128.3; 128.1;

127.7

128.3; 128.1;

127.8

137.7; 137.4

20.59; 20.51

20.76; 20.94

73.1

73.21

127.62; 128.29

127.65; 127.83;

127.95; 128.35

126.88; 127.11;

127.24; 127.56

137.45

137.68

20.20

72.27; 72.42;

72.58

137.18;

137.30;

137.58

137.53

19.67; 19.79

20.90

21.13

72.22

127.39; 126.71

128.2

73.13; 73.39;

73.43

137.3

20.60; 20.91

73.22

127.66; 127.78;

128.28

137.53

21.2; 20.9

20.55; 20.77;

20.89

73.26

127.82; 128.29

137.43

20.77; 20.63

20.58

73.07; 73.29

73.20

127.8

127.27

137.61

136.37;

136.58

136.61

137.48

19.88; 19.66

20.55

72.35

73.32

127.36; 126.79

128.31; 127.73

ORDER

REPRINTS

478

HALILA, BENAZZA, AND DEMAILLY

Table 5. Summary of Benzylated Tetritol and Hexitol Derivatives Obtained via the

Corresponding Stannyl Ether Complexes

Substrate

Isolated Products*

19 R₁ꢁ Bn; R ꢁ R₂ꢁ R₃ꢁ Ac

OH

OR₁

HO

RO

20 R₁ꢁ R₃ꢁ Bn; R ꢁ R₂ꢁ Ac

21 R₁ꢁ R₂ꢁ R₃ꢁ Bn; R ꢁ Ac

23 R₁ꢁ R₂ꢁ R₃ꢁ R ꢁ Ac

OH

OR₃

OR₂

D,L-Threitol (18)

OH

OR₁

OR

OR₃

OR₂

25 R₁ꢁ Bn; R ꢁ R₂ꢁ R₃ꢁ Ac

26 R₁ꢁ R₃ꢁ Bn; R ꢁ R₂ꢁ Ac

27 R₁ꢁ R₂ꢁ R₃ꢁ Bn; R ꢁ Ac

29 R₁ꢁ R₂ꢁ R₃ꢁ R ꢁ Ac

Erythritol (24)

OR₁

RO

31 R₁ꢁ R₂ꢁ Bn; R ꢁ Ac

32 R₁ꢁ Bn; R₂ꢁ R ꢁ Ac

33 R₁ꢁ R₂ꢁ R ꢁ Ac

OR

OR₂

OR

OR₂

D-Malnnitol (30)

OR₁

OR

OR₁

OR

35 R₁ꢁ R₂ꢁ Bn; R ꢁ Ac

36 R₁ꢁ Bn; R₂ꢁ R ꢁ Ac

37 R₁ꢁ R ꢁ Ac; R ꢁ Bn

38 R₁ꢁ R₂ꢁ R ꢁ Ac

RO

OR

OR₂

OR

OR₂

D-Glucitol (34)

OR₁

OR

OR₁

OR

40 R ꢁ R₂ꢁ Bn; R ꢁ Ac

41 R₁ꢁ Bn; R₂ꢁ R ꢁ Ac

42 R₁ꢁ R₂ꢁ R ꢁ Ac

RO

OR

OR₂

OR

OR₂

Galactitol (39)

* After acetylation of crude product

Table 6. Benzylation of Tetritols and Some

Conditions

BnBr

Entry

Substrate

Tin-reagent

(eq)

Solvent

T(°C)

Time(h)

1

2

3

4

5

6

7

8

9

D,L-Threitol (18)

(n-Bu₃Sn)₂O

(1)

(2.5)

(1)

(2.5)

“

(4)

(1.2)

(4)

(1.2)

(4)

“

without

80

“

70

“

5

20

“

Erythritol (24)

“

5

20

240

20

25

30

D-Mannitol (30)

“

D-Glucitol (34)

Galactitol (39)

HCCl₃

without

“

^ppꢁ primary-primary; ^psꢁ primary-secondary; *With complex mixture; **peracetylated alditols

ORDER

REPRINTS

VERSATILE SYNTHESIS OF MONOBENZYLALDITOLS

479

From ribitol (5) (for conditions see entry 4, Table 1) :

2,3,4-Tri-O-acetyl-1,5-di-O-benzylribitol (6). Syrup; Yield 96 mg (16%);

R_f0.67 in 5:3 hexane-EtOAc; MS: m/z 459, M (C₂₅H₃₀O₈) 458.50.

Anal. Calcd for C₂₅H₃₀O₈: C, 65.49; H, 6.60; O, 27.92. Found: C, 65.56; H,

6.65.

2,3,4,5-Tetra-O-acetyl-1-O-benzyl-D,L-ribitol (7). Syrup; Yield 280 mg

(52%); R_f0.55 in 5:2 hexane-EtOAc; MS: m/z 411 [M ꢀ 1], M (C₂₀H₂₆O₉) 410.42.

Anal. Calcd for C₂₀H₂₆O₉: C, 58.53; H, 6.39; O, 35.09. Found: C, 58.72; H,

6.50.

From D-arabinitol (9) (for conditions see entry 5, Table 1) :

2,3,4-Tri-O-acetyl-1,5-di-O-benzyl-D-arabinitol (10). Syrup; Yield 24

mg (4%); R_f0.67 in 5:3 hexane-EtOAc; MS: m/z 459, M (C₂₅H₃₀O₈) 458.50.

Anal. Calcd for C₂₅H₃₀O₈: C, 65.49; H, 6.60; O, 27.92. Found: C, 65.82; H,

6.63.

2,3,4,5-Tetra-O-acetyl-1-O-benzyl-D-arabinitol (11) and 1,2,3,4-tetra-O-

acetyl-5-O-benzyl-D-arabinitol (12). Syrup; Yield 270 mg (50%); R_f0.52 in

5:3 hexane-EtOAc; MS: m/z 411 [M ꢀ 1], M (C₂₀H₂₆O₉) 410.42.

Anal. Calcd C₂₀H₂₆O₉: C, 58.53; H, 6.39; O, 35.09. Found: C, 58.80; H, 6.52.

From D,L-threitol (18) (for conditions see entry 1, Table 6) :

2,3,4-Tri-O-acetyl-1-O-benzyl-D,L-threitol (19). Syrup Yield 299 mg

(54%); R_f0.38 in 6:2 hexane-EtOAc; MS: m/z 339 [M ꢀ 1], M (C₁₇H₂₂O₇) 338.35.

Anal. Calcd for C₁₇H₂₂O₇: C, 60.35; H, 6.55; O, 33.10. Found: C, 60.41; H,

6.63.

2,4-Di-O-acetyl-1,3-di-O-benzyl-D,L-threitol (20). Syrup; Yield 95 mg

(15%); R_f0.41 in 6:2 hexane-EtOAc; MS: m/z 387 [M ꢀ 1], M (C₂₂H₂₆O₆) 386.44.

Hexitols via Their Stannyl Ether Derivatives

Isolated yields (%)

Substrate

Mono-(%)

19

di-(%)

20^{ps (1:3)}

“

26^{ps (1:3)}

“

tri-(%)

(%)**

(54)

(0)

(15)

(17)

(13)

(50)

(15)

(0)

(5)

(23)

(21)

21^1,3,4

(0)

(62)

(0)

(10)

(60)

-

23

“

29

“

33

“

(27)*

“

25

“

27

“

-

(0)*

(36)*

(3)*

(50)

(30)

(5)

“

(0)*

32

“

36/37

41

(45)

(36)

(48)

(47)

31^pp

“

(31)*

(49)*

(29)

35^pp

40^pp

38

42

(25)

ORDER

REPRINTS

480

HALILA, BENAZZA, AND DEMAILLY

Anal. Calcd for C₂₂H₂₆O₆: C, 68.38; H, 6.78; O, 24.84. Found: C, 68.75; H,

6.81.

From D,L-threitol (18) (for conditions see entry 2, Table 5) : The di-O-ben-

zyl derivative 20 was obtained in 17% yield plus:

2-O-acetyl-1,3,4-tri-O-benzyl-D,L-threitol (21). Syrup; Yield 441 mg

(62%); R_f0.56 in 6:2 hexane-EtOAc; MS: m/z 435 [M ꢀ 1], M (C₂₇H₃₀O₅) 434.21.

From erythritol (24) (three sets of conditions):

Entry 3, Table 6: Optimal conditions for primary monobenzylated derivative:

2,3,4-Tri-O-acetyl-1-O-benzyl-D,L-erythritol (25). Syrup; Yield 277 mg

(50%); R_f0.30 in 6:2 hexane-EtOAc; MS: m/z 339[M ꢀ 1], M (C₁₇H₂₂O₇) 338.35.

Anal. Calcd for C₁₇H₂₂O₇: C, 60.35; H, 6.55; O, 33.10. Found: C, 60.83; H,

6.57.

2,4-Di-O-acetyl-1,3-di-O-benzyl-D,L-erythritol (26). Syrup; Yield 82 mg

(13%); Syrup; R_f0.41 in 6:2 hexane-EtOAc; MS: m/z 387 [M ꢀ 1], M (C₂₂H₂₆O₆)

386.44.

Anal. Calcd for C₂₂H₂₆O₆: C, 68.38; H, 6.78; O, 24.84. Found: C, 68.88; H,

6.90.

Entry 4, Table 6: Optimal conditions for 1,3-dibenzylated derivative 26

(50%).

Entry 5, Table 6: Optimal conditions for 1,3,4-tribenzylated derivative 27:

2-O-Acetyl-1,3,4-tri-O-benzyl-D,L-erythritol (27). Syrup; Yield 427 mg

(60%); Syrup; R_f0.58 in 6:2 hexane-EtOAc; MS: m/z 435 [M ꢀ 1], M (C₂₇H₃₀O₅)

434.21.

From D-mannitol (30) (for conditions see entry 6, Table 6):

2,3,4,5,6-Penta-O-acetyl-1-O-benzyl-D-mannitol (32). Syrup; Yield 238

mg (45%); R_f0.44 in 5:3 hexane-EtOAc; MS: m/z 483 [M ꢀ 1], M (C₂₃H₃₀O₁₁)

482.48.

Anal. Calcd for C₂₃H₃₀O₁₁: C, 57.26; H, 6.27; O, 36.48. Found: C, 57.68; H,

6.35.

Under conditions reported in entry 7, the 1,6-dibenzylated derivative was ob-

tained as minor product :

2,3,4,5-Tetra-O-acetyl-1,6-di-O-benzyl-D-mannitol (31). Syrup; Yield

29 mg (5%); R_f0.52 in 5:3 hexane-EtOAc; MS: m/z 531 [M ꢀ 1], M (C₂₈H₃₄O₁₀)

530.56.

Anal. Calcd for C₂₈H₃₄O₁₀: C, 63.39; H, 6.46; O, 30.16. Found: C, 63.45; H,

6.49.

From D-glucitol (34) (for conditions see entry 8, Table 5) :

2,3,4,5,6-Penta-O-acetyl-1-O-benzyl-D-glucitol (36) and 1,2,3,4,5-penta-

O-acetyl-6-O-benzyl-D-glucitol (37). Syrup; Yield 254 mg (48%); R_f0.34 in 5:3

hexane-EtOAc; MS: m/z 483 [M ꢀ 1], M (C₂₃H₃₀O₁₁) 482.48.

ORDER

REPRINTS

VERSATILE SYNTHESIS OF MONOBENZYLALDITOLS

481

Anal. Calcd for C₂₃H₃₀O₁₁: C, 57.26; H, 6.27; O, 36.48. Found: C, 57.73; H,

6.38.

2,3,4,5-Tetra-O-acetyl-1,6-di-O-benzyl-D-glucitol (35). Syrup; Yield 134

mg (23%); R_f0.47 in 5:3 hexane-EtOAc; MS: m/z 531 [M ꢀ 1], M (C₂₈H₃₄O₁₀)

530.56.

Anal. Calcd for C₂₈H₃₄O₁₀: C, 63.39; H, 6.46; O, 30.16. Found: C, 63.72; H,

6.49.

From galactitol (39) (for conditions see entry 9, Table 5):

2,3,4,5-Tetra-O-acetyl-1,6-O-benzylgalactitol (40). Yield 122 mg (21%);

mp 149–151 °C; R_f0.55 in 5:3 hexane-EtOAc; MS: m/z 531 [M ꢀ 1], M

(C₂₈H₃₄O₁₀) 530.56.

Anal. Calcd for C₂₈H₃₄O₁₀: C, 63.39; H, 6.46; O, 30.16. Found: C, 63.68; H,

6.52.

2,3,4,5,6-Penta-O-acetyl-1-O-benzyl-D,L-galactitol (41). Yield 249 mg

(47%); mp 138 °C; R_f0.39 in 5:3 hexane-EtOAc; MS: m/z 483 [M ꢀ 1], M

(C₂₃H₃₀O₁₁) 482.48.

Anal. Calcd for C₂₃H₃₀O₁₁: C, 57.26; H, 6.27; O, 36.48. Found: C, 57.33; H,

6.27.

General procedure for benzyl etherification of pentitols via the stanny-

lene acetal complex. A mixture of pentitols (0.2 g) and dibutyltin oxide in

toluene was refluxed for 16 h with azeotropic removal of water. The white powder

obtained after removal of the solvent was dried under vacuum and treated with ben-

zyl bromide under the conditions reported in Table 1. The crude product obtained

was subsequently acetylated (Ac₂O in pyridine overnight at room temperature).

The syrup obtained after concentration of the solution was dissolved in ethyl ether

and treated with 2,2ꢄ-bipyridyl to precipitate organotin compounds. The filtrate

was concentrated to dryness to give a residue which was processed by column

chromatography on silica gel using a mixture of hexane-AcOEt as eluant.

From xylitol (1): for optimal conditions in monobenzylated derivative 3 see

entry 6, Table 1. The previously described mono and dibenzylated derivatives 3

and 2 were obtained, respectively, in 60 and 5% yields plus:

3,4-Di-O-acetyl-1,2,5-tri-O-benzyl-D,L-xylitol (14). Syrup; Yield 20 mg

(3%); R_f0.65 in 5:2 hexane-EtOAc.

Anal. Calcd for C₃₀H₃₄O₇: C,71.15; H, 6.72; O, 22.13. Found: C,71.02;

H,.6.68.

For optimal conditions in dibenzylated derivative 2 see entry 8, Table 1. The

previously described mono, di and tribenzylated derivatives 3, 2 and 14 were ob-

tained in 28, 52 and 17% yields respectively.

From ribitol (5): for conditions see entry 4, Table 1. The previously described

mono and dibenzylated derivatives 7 and 6 were obtained, respectively, in 31 and

ORDER

REPRINTS

482

HALILA, BENAZZA, AND DEMAILLY

8% yields plus:

2,3,5-Tri-O-acetyl-1,4-di-O-benzyl-D,L-ribitol (15). Syrup; Yield 102

mg (17%); R_f0.62 in 5:3 hexane-EtOAc; MS: m/z 459 [M ꢀ 1], M(C₂₅H₃₀O₈)

458.50.

Anal. Calcd for C₂₅H₃₀O₈: C, 65.49; H, 6.60; O, 27.92. Found: C, 65.67; H,

6.63.

From D-arabinitol (9): for conditions see entry 14, Table 1. The previously

described monobenzylated derivatives 11 and 12 were obtained in 20% overall

yields plus:

2,3-Di-O-acetyl-1,4,5-tri-O-benzyl-D-arabinitol (16). Syrup; Yield 220

mg (33%); R_f0.60 in 5:2 hexane-EtOAc; MS: m/z 507 [M ꢀ 1] M(C₃₀H₂₄O₇)

506.6.

Anal. Calcd for C₃₀H₂₄O₇: C,71.15; H, 6.72; O, 22.13. Found: C,71.23;

H,.6.75.

1,2,3-Tri-O-acetyl-4,5-di-O-benzyl-D-arabinitol (17). Syrup; Yield 151

mg (25%); Syrup; R_f0.47 in 5:2 hexane-EtOAc; MS: m/z 459 [M ꢀ 1]

M(C₂₅H₃₀O₈) 458.5.

ACKNOWLEDGMENTS

The authors thank the Conseil Regional de Picardie for its financial support.

REFERENCES

1. Mukai, C. ; Moharram, S.M.; Hanaoka, M. First total synthesis of (ꢀ)-Secosyrin.

Tetrahedron Lett. 1997, 38, 2511–2512.

2. Letellier, P.; Ralainairina, R.; Beaupère, D.; Uzan, R. Synthesis of new cyclitol

derivatives. Synthesis. 1997, 925–930.

3. a) Grindley, T. B. Applications of tin containing intermediates to carbohydrate chem-

istry. Adv. Carbohydr. Chem. Biochem. 1998, 53, 17–142; b) Grindley, T. B. Appli-

cations of stannyl ether and stannylene acetals to oligosaccharide synthesis. Synthetic

Oligosaccharides: Indispensable Probes for the Life Sciences; Kovàc, P., Ed.; ACS:

Washington, 1994, Chap. 4, pp 51–76; c) David, S.; Hanessian, S. Regioselective ma-

nipulation of hydroxyl groups via organotin derivatives. Tetrahedron. 1985, 41,

643–663.

4. a) Rana, S. S.; Piskorz, C. F.; Barlow, J. J.; Matta, K. L. Selective benzylation of

methyl 2-O-benzyl-ꢅ-L-fucopyranoside and benzyl 2,6-di-O-benzyl-ꢆ-D-galctopy-

ranoside, Carbohydr. Res. 1980, 83, 170–174; b) Eby, R.; Webster, K. T.; Schuerch,

C.; Regioselective alkylation and acylation of carbohydrates engaged in metal com-

plexes. Carbohydr. Res. 1984, 129, 111–120; c) Wessel, H. P.; Iversen, T.; Bundle,

D. R. Acid-catalysed benzylation and allylation by alkyl trichloroacetimidates. J.

Chem. Soc., Perkin Trans. 1. 1985, 2247–2250; d) Flasche, M.; Scharf, H. D. A

ORDER

REPRINTS

VERSATILE SYNTHESIS OF MONOBENZYLALDITOLS

483

straightforward preparation of both enantiomerically pure 2-O-benzyl-erythro-bu-

tanetetrols. Tetrahedron: Asymmetry. 1995, 6, 1543–1546.

5. a) Ichikawa, J.; Asami, M.; Mukaiyama, T. An asymmetric synthesis of glycerol

derivatives by the enantioselective acylation of prochiral glycerol. Chemistry Lett.

1984, 949–952; b) Mukaiyama, T.; Tomioka, I.; Shimizu, M. Asymmetric acylation

of meso-1,2-diols with d-ketopinic acide chloride. Chemistry Lett. 1984, 49–52.

6. Awal, A.; Boyd, A. S. F. ; Buchanan, J. G.; Edgar, A. R. The formation of isopropy-

lidene acetals of erythritol and ribitol under conditions of kinetic control. Carbohydr.

Res. 1990, 205, 173–179.

7. Goodby, J. W.; Haley, J. A.; Watson, M. J.; Mackenzie, G.; S. Kelly, M.; Letellier,

P.; Douillet, O.; Godé, P.; Goethals, G. Ronco, G.; Villa, P. Substitution effects on

the liquid-crystalline properties of D,L-xylitol amphiphiles. Liq. Cryst. 1997, 22,

367–378.

8. a) Mash, E. A.; Kantor, L. T. A.; Waller, S. C. Monobenzylation of 1,n-diols via

dibutylstannylene intermediates. Synth. Commun. 1997, 27, 507–514; b) Qin, H.;

Grindley, T. B. Determination of the configuration of ribitol in the C-polysaccharide

of the streptococcus pneumoniae using a synthetic approach. Can. J. Chem. 1999, 77,

481–494.

9. Glaçon, V.; Benazza, M.; Beaupère, D.; Demailly, G. Heterocyclisation of free or

partially protected alditols via their bis-cyclic sulfate derivatives. Versatile synthesis

of aza and thiodeoxyanhydroalditol with erythro, threo, arabino, gulo, talo, or manno

configuration. Tetrahedron Lett. 2000, 41, 5053–5056.

10. Robert, C. C.; Benazza, M.; Fréchou, C.; Demailly, G. Tin mediated regioselective

etherification and esterification of unprotected xylitol, Carbohydr. Res. 1997, 303,

359–365.

11. Naguashima, N.; Ohno, M. Selective monoalkyltion of acyclic diols by means of

dibutyltin oxide and fluoride salts. Chem. Pharm. Bull. 1991, 39, 1972–1982.

12. Moore, R. E.; Barchi, J. J. Jr.; Bartolini, G. Use of borate complexation in assigning

relative stereochemistry of acyclic polyhydroxylated compounds. J. Org. Chem.

1985, 50, 374–379.

13. a) Benazza, M.; Massoui, M.; Uzan, R.; Demailly, G. Regioselective chlorination

study of unprotected pentitols: syntheses of some 1,5-dichloro-1,5-dideoxypentitol

derivatives. Carbohydr. Res. 1995, 275, 421–431; b) Benazza, M.; Beaupère, D.;

Uzan, R.; Demailly, G. Selective chlorination of pentitols. Carbohydr. Res. 1991,

218, 75–81.

14. Renaud, P.; Lacôte, E.; Quaranta, L. Alternative and mild procedures for the removal

of organotin residues from reaction mixtures. Tetrahedron Lett. 1998, 39, 2123–2126.

Received January 29, 2001

Accepted May 14, 2001

Request Permission or Order Reprints Instantly!

Interested in copying and sharing this article? In most cases, U.S. Copyright

Law requires that you get permission from the article’s rightsholder before

using copyrighted content.

All information and materials found in this article, including but not limited

to text, trademarks, patents, logos, graphics and images (the "Materials"), are

the copyrighted works and other forms of intellectual property of Marcel

Dekker, Inc., or its licensors. All rights not expressly granted are reserved.

Get permission to lawfully reproduce and distribute the Materials or order

reprints quickly and painlessly. Simply click on the "Request

Permission/Reprints Here" link below and follow the instructions. Visit the

U.S. Copyright Office for information on Fair Use limitations of U.S.

copyright law. Please refer to The Association of American Publishers’

(AAP) website for guidelines on Fair Use in the Classroom.

The Materials are for your personal use only and cannot be reformatted,

reposted, resold or distributed by electronic means or otherwise without

permission from Marcel Dekker, Inc. Marcel Dekker, Inc. grants you the

limited right to display the Materials only on your personal computer or

personal wireless device, and to copy and download single copies of such

Materials provided that any copyright, trademark or other notice appearing

on such Materials is also retained by, displayed, copied or downloaded as

part of the Materials and is not removed or obscured, and provided you do

not edit, modify, alter or enhance the Materials. Please refer to our Website

User Agreement for more details.

Order now!

Reprints of this article can also be ordered at

http://www.dekker.com/servlet/product/DOI/101081CAR100106930

Article Doi

Regioselective benzylation of pentitols, tetritols, and some hexitols via their stannyl ether derivatives: Versatile synthesis of monobenzylalditols

DOI: 10.1081/CAR-100106930

Source and publish data:

Authors:

Article abstract of DOI:10.1081/CAR-100106930

Full text of DOI:10.1081/CAR-100106930

Products guided by the article

R&D Labs maybe for 108392-14-9

Relevant to this article

Hot Product