N-Glycosyl-carbamates, -ureas, -isothiocyanates, -thioureas and Related Compounds

13 iV-Glycosyl-carbamates, -ureas, -isothiocyanates, -thioureas and Related Compounds. - N-Glucosyl cyclic carbamates such as 35 were obtained from silver ion-mediated desulfurization - condensation of peracetylated P-i glucopyranosyl isothiocyanate with a-hydroxy-acids. When applied to aliphatic P-hydroxy-acids, the initially formed cyclic carbamates underwent decarboxylation. 3-Hydroxybutanoic acid thus gave 36, while salicylic acid gave 37. The cyclic carbamates 38, prepared from D-glucose, were employed as chiral auxiliaries. Thus N-acylation, conversion to a boron enolate and condensation with 

Reagents i, NaBH4i ii, BU4NF iii, Tbdms—Cl, Im, DMF iv, Dess-Martin oxidation v, Ph3P=CHa Vi, Swern oxidation vii. PhthNH, PhgP, DEAD viii, Hg, Pd/C ix, NH2NH2. MeOH  

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