[(4S,5R)-5-Hydroxymethyl-4-(toluene-4-sulfonyloxy)-tetrahydro-furan-2-yl]-acetic acid ethyl ester

((2R,5R)-4-Oxo-5-trityloxymethyl-tetrahydro-furan-2-yl)-acetic acid ethyl ester

((2R,4R,5R)-4-Hydroxy-5-trityloxymethyl-tetrahydro-furan-2-yl)-acetic acid ethyl ester