MOP glycosyl donor

Scheme 2 Synthesis of 1,2-cir glycosides with unprotected MOP-glycosyl donors.

Scheme 3 l,2-/rcwj-Glycoside synthesis using an unprotected MOP glycosyl donor containing a 2-acetamido group. 

Unprotected MOP glycosyl donors are easily prepared in multigram scale from the corresponding peracetyl glycosyl halides, followed by de-O-acetylation. They are usually crystalline and have excellent shelf life. MOP donors 2,13,18,19, 20, and 22, shown in Scheme 5, are typical examples. 

Oligosaccharide Synthesis by Remote Activation O-Protected 3-Methoxy-2-pyridyloxy (MOP) Glycosyl Donors... 

A. General procedure for the preparation of benzylated MOP glycosyl donors 422... 

B. General procedure for glycosylation with protected MOP glycosyl donors using MeOTf as promoter 422... 

Scheme 4 Disaccharide synthesis with 0-benzyl MOP glycosyl donors using Cu(OTf)2 as promoter.

Scheme 5 Synthesis of I,2-cw-glycosyI disaccharides using MOP glycosyl donors.

Scheme 7 shows examples of 1,2 trans-glycosides synthesized from MOP glycosyl donors that have neighboring participating groups. In the presence of Cu(OTf)2, the... 

Scheme 8 Preparation of T-antigen type () serine glycoside using an MOP glycosyl donor.

A. General Procedure for the Preparation of Benzylated MOP Glycosyl Donors... 

B. General Procedure for Gtycosylation with Protected MOP Glycosyl Donors Using MeOTf as Promoter... 

C. General Procedures for Glycosylation with Protected MOP glycosyl Donors Using Cu(OTf)2 as Promoter... 

In the previous chapter, we briefly discussed the relevance of sialyl Le and we showed a synthesis of a protected derivative that was assembled from a MOP glycosyl donor [see Chap. 18]. This complements several other recently reported syntheses. Herein we describe a straightforward synthesis of sialyl Le employing the TOPCAT activation method as shown in Scheme 6. 

Lou, B, Huynh, H K, Hanessian, S, Oligosaccharide synthesis by remote activation O-protected 3-methoxy-2-pyridyloxy (MOP) glycosyl donors. In Preparative Carbohydrate Chemistry, Hanessian, S, Ed., Marcel Dekker, New York, pp. 413-430, 1997. 

Unprotected MOP glycosyl donors are preparatively stable under neutral or basic conditions, but they can be readily activated by MeOTf in the presence of an excess of... 

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