Abstract
Condensation of 3, 4, 6-tri-O-acetyl-D-glucal and trimethylsilylated nucleobases in the presence of stannic chloride or trimethylsilyl trifluoromethanesulfonate gave anomeric mixtures of 2, 3-dideoxy-D-erythro-hex-2-enopyranosyl nucleosides. The signs of the circular dichroism (CD) spectra of the anomeric 2-hexenopyranosyl nucleosides are opposite to those of usual nucleosides or glucopyranosyl nucleosides. Other examples illustrating the contribution of an unsaturated bond in the sugar portion of nucleosides to the CD spectra are also presented.
