A new synthesis is described of 2-deoxy-D-erythro-pentose [2-deoxy-~-ribose, 2-deoxy-~- arabinose (111, starting from D-glucose. The synthesis proceeds through direct olefination of 2, 4-O-ethylidene-~-erythrose (2) by addition of the stabilized ylides generated from dimethylphosphorylmethyl phenyl sulfide (4) and the corresponding sulfoxide 5. These afford the key intermediates, thio-enol ether 7 and cr, p-unsaturated sulfoxide 8, which ...