Details
| Original language | English |
|---|---|
| Pages (from-to) | 519-528 |
| Number of pages | 10 |
| Journal | Journal of the Chemical Society - Perkin Transactions 1 |
| Issue number | 4 |
| Publication status | Published - 1999 |
| Externally published | Yes |
Abstract
A high yielding allylic oxidation of 3-O-siIylated glycals 5-10 with the reagent system PhI(OAc)2-TMSN3 is presented. The iodine(m) species generated under these conditions is a lot more effective for generating carbohydrate-derived 3-trialkylsiloxy-2,3-dihydro-4//-pyran-4-ones 11-15 than is [hydroxy(tosyloxy)iodo]benzene, the Koser reagent. Even disaccharide 9 containing the oxidation-labile phenylseleno group is smoothly oxidized to the corresponding enone 15. The hypervalent azido iodine reagent is complementary to the Koser reagent, because 3-O-benzylated or -acylated glycals cannot be oxidized. When the iodine(m)-mediated oxidation of 3-O-silylated or -benzylated glycals is followed by a reduction step, the formal 3-O-deblocking of glycals is achieved. In particular, the Luche reduction of enones obtained from the oxidation of lyxo-configured glycals 24, and 26 is highly selective, and exclusively affords the corresponding lyxo-co n figured glycals 28, and 30. In some cases, these products can be transformed under Mitsunobu conditions into glycals with inverted configuration at C-3 in moderate yield.
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In: Journal of the Chemical Society - Perkin Transactions 1, No. 4, 1999, p. 519-528.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - Simple oxidation of 3-O-silylated glycals
T2 - Application in deblocking 3-0-protected glycals
AU - Kirschning, Andreas
AU - Hary, Ulrike
AU - Plumeier, Claus
AU - Ries, Monika
AU - Rose, Lars
PY - 1999
Y1 - 1999
N2 - A high yielding allylic oxidation of 3-O-siIylated glycals 5-10 with the reagent system PhI(OAc)2-TMSN3 is presented. The iodine(m) species generated under these conditions is a lot more effective for generating carbohydrate-derived 3-trialkylsiloxy-2,3-dihydro-4//-pyran-4-ones 11-15 than is [hydroxy(tosyloxy)iodo]benzene, the Koser reagent. Even disaccharide 9 containing the oxidation-labile phenylseleno group is smoothly oxidized to the corresponding enone 15. The hypervalent azido iodine reagent is complementary to the Koser reagent, because 3-O-benzylated or -acylated glycals cannot be oxidized. When the iodine(m)-mediated oxidation of 3-O-silylated or -benzylated glycals is followed by a reduction step, the formal 3-O-deblocking of glycals is achieved. In particular, the Luche reduction of enones obtained from the oxidation of lyxo-configured glycals 24, and 26 is highly selective, and exclusively affords the corresponding lyxo-co n figured glycals 28, and 30. In some cases, these products can be transformed under Mitsunobu conditions into glycals with inverted configuration at C-3 in moderate yield.
AB - A high yielding allylic oxidation of 3-O-siIylated glycals 5-10 with the reagent system PhI(OAc)2-TMSN3 is presented. The iodine(m) species generated under these conditions is a lot more effective for generating carbohydrate-derived 3-trialkylsiloxy-2,3-dihydro-4//-pyran-4-ones 11-15 than is [hydroxy(tosyloxy)iodo]benzene, the Koser reagent. Even disaccharide 9 containing the oxidation-labile phenylseleno group is smoothly oxidized to the corresponding enone 15. The hypervalent azido iodine reagent is complementary to the Koser reagent, because 3-O-benzylated or -acylated glycals cannot be oxidized. When the iodine(m)-mediated oxidation of 3-O-silylated or -benzylated glycals is followed by a reduction step, the formal 3-O-deblocking of glycals is achieved. In particular, the Luche reduction of enones obtained from the oxidation of lyxo-configured glycals 24, and 26 is highly selective, and exclusively affords the corresponding lyxo-co n figured glycals 28, and 30. In some cases, these products can be transformed under Mitsunobu conditions into glycals with inverted configuration at C-3 in moderate yield.
UR - http://www.scopus.com/inward/record.url?scp=0000671309&partnerID=8YFLogxK
U2 - 10.1039/a807479h
DO - 10.1039/a807479h
M3 - Article
AN - SCOPUS:0000671309
SP - 519
EP - 528
JO - Journal of the Chemical Society - Perkin Transactions 1
JF - Journal of the Chemical Society - Perkin Transactions 1
SN - 0300-922X
IS - 4
ER -