Configurational and conformational studies on some benzylidene derivatives of d-ribose and di-β-d-ribofuranose 1,5′:1′,5-dianhydride

Benzylidenation of D-ribose under diverse conditions yields a variety of products, most of which are formed as mixtures of diastereoisomers. The conformations assumed by the furanose rings in the 2,3-O-benzylidene-β-D-ribose derivatives are discussed in relation to the coupling constants obtained by comparing the experimental and computed n.m.r. spectra.