A compound represented by general formula (1) which is useful for producing 3,4'-dideoxymycaminosyltylonolide useful as an antibacterial substance. In the said formula, A represents optionally protected carbonyl; B represents optionally protected formyl; R¹ represents optionally protected hydroxy; R² represents hydrogen or acyl; W represents hydrogen, hydroxy, lower alkanoyloxy or substituted sulfonyloxy; Y represents hydrogen, halogen, hydroxy or substituted sulfonyloxy; and symbol --- represents either a double or a single bond.