Synthetic studies on the carbohydrate part of apoptolidin

1,3-cyclohexadienyl 2-phenylsulfone and 1,3-cycloheptadienyl 2-phenylsulfone which are the precursors for the polypropionate part of apoptolidin, were prepared from the corresponding ketones in kilogram scale. A pyridinium salt strategy made a 5-step, one operation synthesis possible which avoided purification and afforded the final solid products. The process is an economical and environmentally friendly synthesis. The sugar C part was prepared by highly selective methyl addition and iodo-glycosylation from D-glucose. Construction of the sugar D part was achieved from L-rhamnose. Highly beta-selective glycosylation was achieved to give the disaccharide part of apoptolidin by using acetate as a directing group. Also synthetic effort of C21-C28 segment using 1,3-cycloheptadienyl phenylsulfone was described