jo0600510_si_002.cif (14.58 kB)
1-O-Vinyl Glycosides via Tebbe Olefination, Their Use as Chiral Auxiliaries and Monomers
dataset
posted on 2006-07-21, 00:00 authored by Jialong Yuan, Kristof Lindner, Holger FrauenrathA series of anomerically pure 1-O-formyl glycosides 1 was prepared and converted into the corresponding
1-O-vinyl glycosides 2 by Tebbe olefination. The unsubstituted vinyl glycosides were obtained as
anomerically pure compounds in good yields, and the method of preparation was compatible with the
presence of a variety of functional groups. Remarkably, the anomeric formate group was regioselectively
converted into the corresponding olefin in the presence of acetate and benzoate protecting groups. With
the perspective to use the 1-O-vinyl glycosides as monomers for the preparation of glycosylated poly(vinyl alcohol) derivatives with controlled tacticity, their scope as chiral auxiliaries for a stereodifferentiation in addition reactions to the olefin function was investigated by using the [2+2] cycloaddition
to dichloroketene as a model reaction. In particular, vinyl 2,3,4,6-tetra-O-benzoyl-α-d-mannopyranoside
(2i) exhibited excellent diastereoselectivity. Finally, the 1-O-vinyl glycosides were successfully subjected
to radical homopolymerization in bulk or used as electron-rich comonomers in radical copolymerizations
with maleic anhydride, yielding alternating, glycosylated poly(vinyl alcohol-alt-maleic anhydride).