The Petasis-Ferrier rearrangement: developments and applications.

In the mid-1990s, Petasis reexamined a promising but infrequently used rearrangement strategy, the so-called Ferrier-type-II reaction, and provided it with a modern update. Previously, Ferrier had developed a strategy where carbohydrate derivatives would undergo a fragmentation/aldol-type recombination sequence, generating a carbocycle, albeit under the promotion of stoichiometric mercury salts. Petasis' new variant showed the promise to effectively and stereoselectively convert a range of cyclic vinyl acetals to useful tetrahydrofurans and tetrahydropyrans, using less toxic promoters. Since these first reports, the 'Petasis-Ferrier rearrangement' has represented a vibrant area of research and innovation for organic chemists. With numerous applications in complex natural product total synthesis, the utility of the reaction has been resoundingly established. Recent developments have extended the reaction to a broader synthetic context, allowing for in situ generation of rearrangement substrates and more liberal interpretation of what fragmentation/recombination reactions warrant the designation of a Petasis-Ferrier rearrangement.