Recent developments in the construction of trans-fused polycyclic ethers.

The development of new synthetic methodology for the construction of trans-fused polycyclic ethers has stimulated significant attention since the late 1980s. This review provides an update on work reported between 2000 and 2002, emphasizing the development of iterative, convergent and cascade/two-directional cyclization strategies that provide direct and efficient approaches for the assembly of these complex structures. Recent developments in synthetic methodology have provided the tools necessary to accomplish the first total syntheses of ciguatoxin CTX3C and gambierol. Nonetheless, significant improvements in selectivity and versatility are clearly necessary for progress to be made in the construction of this class of molecules.