Reinvestigation of the Synthesis of (2R,3R) 2,3-(Cyclohexylidenedioxy)-4-cyclopentenone as Possible Building Block for the Synthesis of Carbocyclic Nucleosides.

An in depth study of the four-steps synthesis of (2R,3R) 2,3-(cyclohexylidenedioxy)-4-cyclopentenone (5) from D-ribonolactone (1) is described. From these experiments we must conclude that the overall yield reported in the literature (65%) is overestimated. All compounds have been throughly investigated by 1H- and 13C-NMR spectroscopy.