Synthetic studies on CP-225,917 and CP-263,114: access to advanced tetracyclic systems by intramolecular conjugate displacement and [2,3]-Wittig rearrangement.

An advanced intermediate related to the structures of CP-225,917 and CP-263,114 was constructed by a sequence based on the use of Grob-like fragmentation, intramolecular conjugate displacement, and [2,3]-Wittig rearrangement. A variant of the [2,3]-Wittig rearrangement was developed.