2-amino-2-deoxyglycosides

Additions to glycals can also give products from which glycosylating agents can be made for the specific synthesis of 2-amino-2-deoxyglycosides, and this approach adds to the methods available for making such glycosides... 

SCHEME 3.26 Approaches utilized for the synthesis of 2-amino-2-deoxyglycosides from glycals. 

Reference is made in Chapters 13 and 24 to the synthesis of /8-lactams by the addition of trichloroacetyl isocyanate to glycal derivatives followed by periodate cleavage of the sugar rings, and bis(trichloroethyl)azodicarboxylate adds to such compounds to afford a route to 2-amino-2-deoxyglycosides (Chapter 9). A novel cycloaddition reaction is illustrated in Scheme 6A. ... 

SCHEME 4.5 1,2-Migration in the stereoselective synthesis of 1, 2-tram (amino)-glyco-sides and 2-deoxyglycosides as reported by (a) Danishefsky, (b) Yu, and (c) Lowary. Ac, acetyl All, allyl Bn, benzyl Bz, benzoyl DTBMP, 2,6-di-fert-butyl-4-mcthyl pyridine TBDPS, ferf-butyldiphenylsilyl THF, tetrahydrofuran TIPS, triisopropylsilyl Tol, 4-tolyl. 

The stability toward acid-catalyzed hydrolysis of the 6-amino-6-deoxy-D-glycosides has been reported -" (see, however, Ref. 121). The stability of the 6-amino-6-deoxyglycoside must be at least partly due to the shielding effect of the — NH3+ oup. Likewise, the acid stability of 6-deoxy-6-iodo-D-glucosides has been noted. -"... 

A mixture of D-mycinosyl fluoride, 2 eqs. of cyclohexylmethanol, and powdered 4 A molecular sieves in benzene treated with 5 eqs. Cp ZrCF followed by 5 eqs. AgC104, and stirred at room temp, for 10 min - product. V 92% (a P 1 16). The reaction is rapid and clean, and the Ag(I) salt essential. Stereoselectivity was low in ether or acetonitrile. F.e.s. T. Matsumoto et al.. Tetrahedron Letters 29, 3567-70, 3575-8 (1988) p-3-amino-3-deoxyglycosides with Cp2HfCl2/AgC104 cf. ibid. 3571-4 s.a. Chem. Letters 1989, 437-40. 

---