Modified Wittig–Claisen tandem reaction
Modified Wittig–Claisen tandem reaction is a one‑pot cascade that links the Wittig reaction with a Claisen rearrangement. In this sequence, the Wittig step forms an allyl vinyl ether, which then undergoes a Claisen rearrangement to give a γ,δ‑unsaturated ketone or aldehyde. This approach is a useful retrosynthetic tool for assembling complex molecules, and it is especially good for making cyclic ketones that bear a double bond at the γ,δ position.
Two notable applications illustrate its value:
- Paquette and co‑workers combined a Tebbe olefination (a Wittig‑like reaction) with a Claisen rearrangement to construct 4‑cyclooctenone by expanding a six‑membered ring of a 2‑cyclohexanone.
- The tandem Wittig–Claisen sequence has been used to build the spiro[pyrrolidin‑3,3’‑oxindole] framework found in natural products such as horsfiline. Starting from o‑nitrobenzaldehyde, the sequence yields a 4‑pentenal intermediate that can be further converted into horsfiline, an active ingredient in traditional medicine with analgesic effects.
This page was last edited on 3 February 2026, at 08:47 (CET).