| abstract |
The invention relates to processes for the preparation of compounds having a fused ring structure of the formula. These compounds include ecteinascidins and spiroamine-1,4-bridge. The 1,4-bridged method is carried out using a 1-labile, 10-hydroxy, 18-protected hydroxy, di-6,8-ene-5 -one condensed ring compound. After formation of the 1,4-bridge, protection at C-18 is removed prior to spiroamine administration. |