
TY  - JOUR
A1  - Taylor, C. M. 
A1  - Weir, C. A. 
A1  - Jørgensen, C. G. 
T1  - Synthesis of <font size="-2">D</font>-Galactopyranosides of <emph type="2">trans</emph>-4-Hydroxy-<font size="-2">L</font>-proline Utilizing the Sulfoxide Glycosylation Method
JF  - Australian Journal of Chemistry
JO  - Aust. J. Chem.
Y1  - 2002
VL  - 55
IS  - 2
SP  - 135
EP  - 140
KW  - 
UR  - https://doi.org/10.1071/CH01156 
N2  - Phenyl 1-thio-&#946;-D-galactopyranoside (1) was converted into two sulfoxide glycosyl donors: phenyl (2,3,4,6-tetra-O-benzyl)-1-thio-&#946;-D-galactopyranoside S-oxide (3) and phenyl (2,3,4,6-tetra-O-pivaloyl)- 1-thio-&#946;-D-galactopyranoside S-oxide (5). These glycosyl donors were then each reacted with Na- fluorenylmethoxycarbonyl-trans-4-hydroxy-L-proline allyl ester (7). The glycosylation reactions were conducted at -70&#176;C with triflic anhydride as promotor, in the presence of 2,6-di-tert-butyl-4-methylpyridine. In the case of the perbenzylated sulfoxide donor (3), the major product was Na-fluorenylmethoxycarbonyl-trans-4-hydroxy- 4-O-[(2,3,4,6-tetra-O-benzyl)-a-D-galactopyranosyl]-L-proline allyl ester (8a). In dichloromethane, the a-to-&#946; ratio was 3 : 1 and in toluene this improved to 5 : 1, with a combined yield of 41%. In the case of the perpivaloylated sulfoxide donor (5), Na-fluorenylmethoxycarbonyl-trans-4-hydroxy-4-O-[(2,3,4,6-tetra-O-pivaloyl)-&#946;-D- galactopyranosyl]-L-proline allyl ester (9) was obtained as the sole glycoside product in 46% yield. 
ER  -

