Mild but efficient methods for stereoselective glycosylation with thioglycosides: Activation by [N-phenylselenophthalimide-Mg(ClO4)2] and [PhIO-Mg(ClO4)2]

Synlett

Volumn , Issue 1, 1998, Pages 84-86

  Fukase, Koichi ^a   Nakai, Yoshihiko ^a   Kanoh, Takeshi ^a   Kusumoto, Shoichi ^a  

^a OSAKA UNIVERSITY   (Japan)

Author keywords

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Indexed keywords

EID: 0012862794     PISSN: 09365214     EISSN: None     Source Type: Journal    
DOI: 10.1055/s-1998-1575     Document Type: Article

References (14)

1. Fukase, K.; Hasuoka, A.; Kusumoto, S. Tetrahedron Lett. 1993, 34, 2187.
2. Fukase, K.; Hasuoka, A.; Kinoshita, I.; Aoki, Y.; Kusumoto, S. Tetrahedron 1995, 51, 4923.
3. Fukase, K.; Hasuoka, A.; Kinoshita, I.; Kusumoto, S. Tetrahedron Lett. 1992, 33, 7165.
4. Fukase, K.; Kinoshita, I.; Kanoh, T.; Hasuoka, A.; Kusumoto, S. Tetrahedron 1996, 52, 3897.
5. 9,10 the corresponding α-glucosides were obtained in sufficiently high stereoselectivity but the yields were low because of the formation of the corresponding glycosyl bromide.
6. Shimizu, H.; Ito, Y.; Ogawa, T. Synlett 1994, 535.
7. 2 was reduced to 0.25 equiv to the donor, the reaction took a longer period (ca. 1.5 times) for completion. But no such obvious difference in the reaction rate was observed when the amount of the perchlorate was increased from 0.5 to 1.0 equiv.
8. 4, and concentrated in vacuo. The residue was purified by silica-gel column chromatography to give a product.
9. Fukase, K.; Yoshimura, T.; Kotani, S.; Kusumoto, S. Bull. Chem. Soc. Jpn. 1994, 67, 473.
10. Suda, Y.; Bird, K.; Shiyama, T.; Koshida, S.; Marques, D.; Fukase, K.; Sobel, M.; Kusumoto, S. Tetrahedron Lett. 1996, 37, 1053.
11. 4 is also a good catalyst for α-selective glycosylation.
12. Previously, Houdier et al. reported that bulky 6-O-substituents such as Trt or t-butyldimethylsilyl groups increase significantly the proportion of α product in the iodonium dicollidine perchlorate-promoted glycosylation with pent-5-enyl and thioethyl glycosides: Houdier, S.; Vottero, P. J. A. Carbohydr. Res. 1992, 232, 349. Recently, Boons et al. also reported that the 6-O-Trt group in thioglycosides withstand glycosylation with N-iodosuccinimide (NIS) and a catalytic amount of triflic acid and favors the formation of α-glycosides. A combination of NIS-trimethylsilyl triflate was also shown to be effective.
13. The α-selectivity, as far as given in their paper, is lower than that in our present work: Boons, G.-J.; Bowers, S; Coe, D. M. Tetrahedron Lett. 1997, 38, 3773. Probably because of the cleavage of the Trt group during the reaction, the yields of the glycosylation were generally moderate in these papers.
14. Glycosylation with glycosyl fluorides catalyzed by lanthanide perchlorates: Kim, W.-S.; Hosono, S.; Sasai, H.; Shibasaki, M. Tetrahedron Lett. 1995, 36, 4443.