The synthesis of four dideoxygenated analogues of β-maltosyl-(1→4)-trehalose

Article abstract of DOI:10.1080/07328309808001900

Four derivatives of β-maltosyl-(1→4)-trehalose were prepared, each with two deoxy functions in one of the constitutive disaccharide building blocks. 2,3-Di-O-acetyl-4,6-dideoxy-4,6-diiodo-α-D-galactopyranosyl-(1→4) -1,2,3,6-tetra-O-acetyl-D-glucopyranose (3) was employed as a precursor for the 4''',6'''-dideoxygenated tetrasaccharide 9: coupling of 3 with 2,3,6-tri-O-benzyl-α-D-glucopyranosyl 2,3,6-tri-O-benzylidene-α-D-glucopyranoside (4) furnished the tetrasaccharide 5 which was deiodinated and deprotected to yield the target tetrasaccharide 9. Secondly, the dideoxygenated maltose derivative 3-deoxy-4,6-O-isopropylidene-2-O-pivaloyl-α-D-glucopyranosyl-(1→4) -1,6-anhydro-3-deoxy-2-O-pivaloyl-β-D-glucopyranose (10) was ring-opened to the anomeric acetate 11. A [2+2] block synthesis with 4 in TMS triflate mediated glycosylation gave a tetrasaccharide which was deprotected to the 3'',3'''-dideoxygenated analogue of β-maltosyl-(1→4)-trehalose. For the third tetrasaccharide, 2,3,2',3'-tetra-O-benzyl-α,α-trehalose was iodinated at the primary positions and deiodinated in the presence of palladium-on-carbon, then this acceptor was selectively glycosylated with hepta-O-acetylmaltosyl bromide (20). Removal of protective groups furnished the maltosyl trehalose tetrasaccharide deoxygenated at positions C-6 and C-6'. To prepare a 3,3'-dideoxygenated trehalose, the free hydroxyl groups of 2-O-benzyl-4,6-O-(A)-benzylidene-α-D-glucopyranosyl 2-O-benzyl-4,6-O-(R)-benzylidene-α-D-glucopyranoside (25) were reduced by Barton-McCombie deoxygenation. One of the benzylidene groups was opened reductively with sodium cyanoborohydride. The resulting free hydroxyl group at the 4'-position was glycosylated in a Koenigs-Knorr reaction with 20 to yield the 3,3'-dideoxygenated tetrasaccharide 32, the fourth target oligosaccharide, after deprotection.

Full text of DOI:10.1080/07328309808001900

Journal of Carbohydrate Chemistry
ISSN: 0732-8303 (Print) 1532-2327 (Online) Journal homepage: http://www.tandfonline.com/loi/lcar20
The Synthesis of Four Dideoxygenated Analogues
of β-Maltosyl-(1→4)-Trehalose
Hans Peter Wessel , Rudolf Minder & Michel Trumtel
To cite this article: Hans Peter Wessel , Rudolf Minder & Michel Trumtel (1998) The Synthesis
of Four Dideoxygenated Analogues of β-Maltosyl-(1→4)-Trehalose, Journal of Carbohydrate
Chemistry, 17:8, 1283-1306, DOI: 10.1080/07328309808001900
To link to this article: http://dx.doi.org/10.1080/07328309808001900
Published online: 16 Aug 2006.
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Date: 11 June 2016, At: 01:27