Glycosyl Trichloroacetimidates
3.2
517
7 Conclusions
The requirement for efficient glycosylation methods, as outlined at the beginning of this chapter, namely convenient diastereocontrolled anomeric O-activation (first step) and subsequent
efficient diastereocontrolled glycosylation promoted by catalytic amounts of a promoter (second step) are essentially completely fulfilled by the trichloroacetimidate method. In terms of
reactivity and applicability toward different acceptors, the O-glycosyl trichloroacetimidates
have generally proven to be outstanding glycosyl donors, which resemble in various respects
the nucleoside diphosphate sugar derivatives used by nature as glycosyl donors. Thus, basecatalyzed generation of O-glycosyl trichloroacetimidates followed by acid-catalyzed glycosylation have become a very competitive alternative to other methods mainly requiring anomeric
oxygen exchange reactions for glycosyl donor generation and at least equimolar amounts of
a promoter system for the glycosylation step. Hence, the trichloroacetimidate method can readily be adapted for large-scale preparations. Recently, related activation systems have attracted
increasing interest, thus widening the scope of this glycosylation method.
Acknowledgement
Our work reported in this chapter was supported by the Deutsche Forschungsgemeinschaft and
the Fonds der Chemischen Industrie.
References
1. Schmidt RR (1986) Angew Chem Int Ed Engl
25:89
2. Schmidt RR, Kinzy W (1994) Adv Carbohydr
Chem Biochem 50:21
3. Schmidt RR, Jung KH (1997) Oligosaccharide
Synthesis via Trichloroacetimidates. In: Hannessian S (ed) Preparative Carbohydrate Chemistry.
Marcel Dekker, p 283
4. Schmidt RR, Jung KH (2000) Trichloroacetimidates. In: Ernst B, Hart GW, Sinaÿ P (eds) Carbohydrates in Chemistry and Biology, Part I:
Chemistry of Saccharides, vol 1. Wiley-VCH,
Weinheim, p 5
5. Paulsen H (1982) Angew Chem Int Ed Engl
21:155
6. Kunz H (1987) Angew Chem Int Ed Engl
26:294; (1993) Pure Appl Chem 65:1223
7. Toshima K, Tatsuta K (1993) Chem Rev
93:1503
8. Schmidt RR, Reichrath M (1979) Angew Chem
Int Ed Engl 18:466
9. Klotz W, Schmidt RR (1994) J Carbohydr Chem
13:1093
10. Schmidt RR, Klotz W (1991) Synlett 168
11. Klotz W, Schmidt RR (1993) Liebigs Ann Chem
683
12. Michel J (1983) PhD thesis, Universität Konstanz
13. Schmidt RR, Michel J (1980) Angew Chem Int
Ed Engl 19:731
14. Pougny JR, Sinaÿ P (1976) Tetrahedron Lett
4073
15. Sinaÿ P (1978) Pure Appl Chem 50:1437
16. Ohashi I, Lear MJ, Yoshimura F, Dirama M
(2004) Org Lett 6:719
17. Chiara JL, Encinas L, Díaz B (2005) Tetrahedron Lett 46:2445
18. Yoshizaki H, Fukuda N, Sato K, Oikawa M,
Fukase K, Suda Y, Kusumoto S (2001) Angew
Chem Int Ed 40:1475
19. Oikawa M, Tanaka T, Fukuda, N, Kusumoto S
(2004) Tetrahedron Lett 45:4039
20. Roussel F, Knerr L, Grathwohl M, Schmidt RR
(2000) Org Lett 2:3043
21. Knerr L, Schmidt RR (2001) The Use of O-Glycosyl Trichloroacetimidates for the Polymer
Supported Synthesis of Oligosaccharides. In:
Seeberger PH (ed) Solid Support Oligosaccha-
3.2
517
7 Conclusions
The requirement for efficient glycosylation methods, as outlined at the beginning of this chapter, namely convenient diastereocontrolled anomeric O-activation (first step) and subsequent
efficient diastereocontrolled glycosylation promoted by catalytic amounts of a promoter (second step) are essentially completely fulfilled by the trichloroacetimidate method. In terms of
reactivity and applicability toward different acceptors, the O-glycosyl trichloroacetimidates
have generally proven to be outstanding glycosyl donors, which resemble in various respects
the nucleoside diphosphate sugar derivatives used by nature as glycosyl donors. Thus, basecatalyzed generation of O-glycosyl trichloroacetimidates followed by acid-catalyzed glycosylation have become a very competitive alternative to other methods mainly requiring anomeric
oxygen exchange reactions for glycosyl donor generation and at least equimolar amounts of
a promoter system for the glycosylation step. Hence, the trichloroacetimidate method can readily be adapted for large-scale preparations. Recently, related activation systems have attracted
increasing interest, thus widening the scope of this glycosylation method.
Acknowledgement
Our work reported in this chapter was supported by the Deutsche Forschungsgemeinschaft and
the Fonds der Chemischen Industrie.
References
1. Schmidt RR (1986) Angew Chem Int Ed Engl
25:89
2. Schmidt RR, Kinzy W (1994) Adv Carbohydr
Chem Biochem 50:21
3. Schmidt RR, Jung KH (1997) Oligosaccharide
Synthesis via Trichloroacetimidates. In: Hannessian S (ed) Preparative Carbohydrate Chemistry.
Marcel Dekker, p 283
4. Schmidt RR, Jung KH (2000) Trichloroacetimidates. In: Ernst B, Hart GW, Sinaÿ P (eds) Carbohydrates in Chemistry and Biology, Part I:
Chemistry of Saccharides, vol 1. Wiley-VCH,
Weinheim, p 5
5. Paulsen H (1982) Angew Chem Int Ed Engl
21:155
6. Kunz H (1987) Angew Chem Int Ed Engl
26:294; (1993) Pure Appl Chem 65:1223
7. Toshima K, Tatsuta K (1993) Chem Rev
93:1503
8. Schmidt RR, Reichrath M (1979) Angew Chem
Int Ed Engl 18:466
9. Klotz W, Schmidt RR (1994) J Carbohydr Chem
13:1093
10. Schmidt RR, Klotz W (1991) Synlett 168
11. Klotz W, Schmidt RR (1993) Liebigs Ann Chem
683
12. Michel J (1983) PhD thesis, Universität Konstanz
13. Schmidt RR, Michel J (1980) Angew Chem Int
Ed Engl 19:731
14. Pougny JR, Sinaÿ P (1976) Tetrahedron Lett
4073
15. Sinaÿ P (1978) Pure Appl Chem 50:1437
16. Ohashi I, Lear MJ, Yoshimura F, Dirama M
(2004) Org Lett 6:719
17. Chiara JL, Encinas L, Díaz B (2005) Tetrahedron Lett 46:2445
18. Yoshizaki H, Fukuda N, Sato K, Oikawa M,
Fukase K, Suda Y, Kusumoto S (2001) Angew
Chem Int Ed 40:1475
19. Oikawa M, Tanaka T, Fukuda, N, Kusumoto S
(2004) Tetrahedron Lett 45:4039
20. Roussel F, Knerr L, Grathwohl M, Schmidt RR
(2000) Org Lett 2:3043
21. Knerr L, Schmidt RR (2001) The Use of O-Glycosyl Trichloroacetimidates for the Polymer
Supported Synthesis of Oligosaccharides. In:
Seeberger PH (ed) Solid Support Oligosaccha-