Synthesis of the optically active key intermediate of FR901483

Efficient synthesis of the tricyclic key intermediate 2 for (−)-FR901483 1 was accomplished. The precursor of the intramolecular aldol reaction 4b is constructed by the Ugi 4CC reaction and subsequent intramolecular Dieckmann condensation. This approach allows a fully stereocontrolled total synthesis of (−)-FR901483, which would provide various derivatives.