- A 3,4-trans-fused cyclic protecting group facilitates α-selective catalytic synthesis of 2-deoxyglycosides
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A practical approach has been developed to convert glucals and rhamnals into disaccharides or glycoconjugates with high α-selectivity and yields (77-97 %) using a trans-fused cyclic 3,4-O-disiloxane protecting group and TsOH·H2O (1 mol %) as a catalyst. Control of the anomeric selectivity arises from conformational locking of the intermediate oxacarbenium cation. Glucals outperform rhamnals because the C6 side-chain conformation augments the selectivity.
- Balmond, Edward I.,Benito-Alifonso, David,Coe, Diane M.,Alder, Roger W.,McGarrigle, Eoghan M.,Galan, M. Carmen
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supporting information
p. 8190 - 8194
(2014/08/18)
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- Stereocontrolled total synthesis of polygalolide A
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The total synthesis of polygalolide A, a secondary metabolite that was isolated from a Chinese medicinal plant, is reported. A key issue in this synthesis was construction of an oxabicyclo[3.2.1] skeleton, which was solved by the development of an intramo
- Yamada, Hitomi,Adachi, Masaatsu,Isobe, Minoru,Nishikawa, Toshio
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supporting information
p. 1428 - 1435
(2013/07/26)
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- Total synthesis of polygalolide A
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The total synthesis of polygalolide A was accomplished through intramolecular C-glycosylation of glucal modified with siloxyfuran. The siloxyfuran group and siloxy substituent at the C-3 position played crucial roles in allowing direct access to the highl
- Adachi, Masaatsu,Yamada, Hitomi,Isobe, Minoru,Nishikawa, Toshio
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supporting information; experimental part
p. 6532 - 6535
(2012/02/15)
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- One-pot conversion of glycals to cis-1,2-isopropylidene-α-glycosides
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Described is a general method for the conversion of glycals to the corresponding 1,2-cis-isopropylidene-α-glycosides. Epoxidation of glycals with dimethyldioxirane followed by ZnCl2-catalyzed addition of acetone converted a variety of protected glycals into 1,2-cis-isopropylidene-α-glycosides in good yield. The reaction is compatible with a range of protecting groups, including esters, benzyl ethers, and silyl ethers, as well as free hydroxyl groups. This method has been applied to develop a synthesis of protected glucuronic acid 1, a key intermediate in the synthesis of glycosaminoglycans. Compound 1 was produced in seven steps and 32% overall yield.
- Lohman, Gregory J. S.,Seeberger, Peter H.
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p. 7541 - 7543
(2007/10/03)
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