described. The two key intermediates 3 and 55, representing the AB and EFGH ring frameworks, were prepared from 2-deoxy-d-ribose via linear sequences. Brown's asymmetric allylboration and the intramolecular hetero-Michael reaction were successfully applied to the construction of the A ring moiety. Synthesis of the EFGH ring segment 55 was achieved by the SmI2 mediated reductive cyclization, constructing