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Trichloroacetimidate formation

The synthesis and application of 0-glucosyl trichloroacetimidates is focused on 0-benzyl- and 0-acetyl protected derivatives (1,52a) because these two protective groups have proven to be the most valuable in glycoside synthesis. Representative examples of trichloroacetimidate formation are collected in Table I (la- Id). As already outlined (Section III. 1), the glucosyl trichloroacetimidates are obtained in high yields and the diastereoselectivi-... [Pg.34]

Table XXIX demonstrates that various protective-group patterns are compatible with trichloroacetimidate formation, and not only a but also / derivatives may be generated highly selectively, as for instance 29 b-/ (149)... Table XXIX demonstrates that various protective-group patterns are compatible with trichloroacetimidate formation, and not only a but also / derivatives may be generated highly selectively, as for instance 29 b-/ (149)...
Glycosyl donor Trichloroacetimidate formation Glycosyl acceptor0 Reaction conditions Reference... [Pg.108]

II. THE TRICHLOROACETIMIDATE METHOD A. Trichloroacetimidate Formation (Activation Step)... [Pg.289]

Features of the activation step are (1) convenient base-catalyzed trichloroacetimidate formation (2) controlled access to a- or P-compounds by choice of the base (3) thermal... [Pg.295]

R. R. Schmidt and J. Michel, Direct 0-glycosyl trichloroacetimidate formation. Nucleophilicity of the anomeric oxygen atom. Tetrahedron Lett. 25 821 (1984). [Pg.336]

The synthesis of the tetramannose donor 93 (Scheme 13.13) resembled that of Schmidt s syntheses of yeast GPI and rat brain Thy-1 GPI [44, 53], A series of glycosylations started with the formation of the Man(al- 6) bond between trichloro-acetimidate 34 and 6-alcohol 90 in the presence of TMSOTf. Iterative removal of the 02 protecting group and glycosylations with mannosyl donors 91 and 34 completed the tetramannose 92. To achieve the glycosyl donor 93, the allyl group was removed with PdCl2, followed by trichloroacetimidate formation. [Pg.341]

Glycosyl trichloroacetimidate formation and acid-catalyzed glycosyladon of acceptors HOR ... [Pg.458]

O-Glycosyl trichloroacetimidates have become popular because they are easily available, powerful glycosyl donors. Therefore, investigations were undertaken to provide glycosyl donors which follow the principle of 0-glycosyl trichloroacetimidate formation and activation. A short outline of this work is attached here. [Pg.516]

The Trichloroacetimidate Method Derivation of New Principles for Glycoside Synthesis Trichloroacetimidate Formation... [Pg.33]

Deprotonation. The use of DBU in Wittig reaction and Overman rearrangement (in the trichloroacetimidate formation step) is advantageous. [Pg.129]

Figure 3.39 Formation of anomeric pairs of glycosyl trichloroacetimidates and 2,4-dinitrophenolates. Anhydrous caesium carbonate is also used for trichloroacetimidate formation. In the 2,4-dinitrophenolate epimerisat-ion, nucleophilic attack by oxygen rather than sulfur is proposed since sp -hybridised carbon is a hard electrophile. Figure 3.39 Formation of anomeric pairs of glycosyl trichloroacetimidates and 2,4-dinitrophenolates. Anhydrous caesium carbonate is also used for trichloroacetimidate formation. In the 2,4-dinitrophenolate epimerisat-ion, nucleophilic attack by oxygen rather than sulfur is proposed since sp -hybridised carbon is a hard electrophile.
See other pages where Trichloroacetimidate formation is mentioned: [Pg.194]    [Pg.29]    [Pg.30]    [Pg.41]    [Pg.53]    [Pg.58]    [Pg.103]    [Pg.103]    [Pg.283]    [Pg.232]    [Pg.525]    [Pg.615]    [Pg.479]    [Pg.460]    [Pg.460]    [Pg.54]    [Pg.214]    [Pg.511]    [Pg.602]    [Pg.127]    [Pg.479]    [Pg.220]    [Pg.264]    [Pg.54]   
See also in sourсe #XX -- [ Pg.275 ]



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