Efficient conditions for the synthesis of C-glycosylidene compounds from lactones based on Wittig reactions of cyanomethyl triphenylphosphoranylidene involving microwave heating are described: subsequent stereoselective reduction of the anomeric olefins gave the corresponding C-glycosides in good yields with high stereocontrol.
The first synthesis of 1,4-diazepine 2,5-dione peptides containing a β-aminoacid in which the β carbon is also the anomeric carbon of a furanoid sugar is described. These new anomeric spirosugars obtained with a stereoselective control in the d-gulo, d-manno, d-allo and d-ribo series can be regarded as the first members of a new class of spironucleosides. In the course of our study, two symmetrical