We have previously clarified that the strongly electron-withdrawing CF3 group nicely affected base-mediated proton shift of CF3-containing propargylic or allylic alcohols to afford corresponding α,β-unsaturated saturated ketones, respectively, which was applied this time Claisen rearrangement after O-allylation with a group, followed by isomerization allyl vinyl ethers via shift, enabling desir...

The title compound, C(16)H(18)F(6)O(4), was obtained through an unprecedented one-pot reaction sequence involving a Gosteli-Claisen rearrangement and a cyclo-isomerization. The constitution and relative configuration were determined by single-crystal X-ray diffraction analysis. In the crystal, mol-ecules are connected via O-H ⋯ O hydrogen bonds.

A series of ynenyl allyl ethers were rearranged into polysubstituted furans in the presence of a gold(I) catalyst. It is proposed that the transformation involves a Claisen-type rearrangement that allows the efficient creation of quaternary centers under mild experimental conditions.

Synthesis of substituted 1,3-dienes was achieved via gold(I)-catalyzed Claisen rearrangement of allenyl vinyl ethers. The N-heterocyclic carbene gold chloride catalyst (IPrAuCl) was superior in terms of activity and selectivity and afforded the 3,3-product in excellent yields. A proposed cation-π inter-action played a significant role in affecting the reaction rate.

2,2,5-Trisubstituted pyrrolidines are available from allylic pyroglutamates by Ireland-Claisen ester rearrangement followed by Eschenmoser sulfide contraction and reduction in a highly diastereoselective and efficient sequence. Some of the products from this sequence exhibit activity against S. aureus, but are much less active against E. coli.

[structure: see text] Symmetrical and unsymmetrical 2',7'-dichlorofluorescein (DCF) derivatives have been synthesized by means of Mannich reactions and an aromatic Claisen rearrangement. NMR and fluorescence spectroscopic studies reveal the correlation between the conformations, the photoinduced electron transfer mechanism, and fluorescent intensities of these DCF derivatives. Two quenching nit...

The synthesis of dehaloperophoramidine, a non-halogenated derivative of the marine natural product perophoramidine, and its biological activity towards HCT116, HT29 and LoVo colorectal carcinoma cells is reported. A [3,3]-Claisen rearrangement and an epoxide opening/allylsilylation reaction installed the contiguous all-carbon quaternary stereocentres with the required relative stereochemistry.

The Claisen rearrangement of sugar derived allyl vinyl ether, Wittig olefination and intramolecular acetalization reactions were used as key steps in the first stereoselective total synthesis of neosemburin and isoneosemburin through the formation of a 3-C-branched sugar precursor as a key intermediate.

[reaction: see text] Two different routes to the tricyclic core of Garcinia-derived natural products are described. The first approach is based on a tandem Claisen/Diels-Alder rearrangement and delivers the desired lactone 14. The second approach, employing a Wessely oxidation/Diels-Alder protocol, leads to the same caged heterocycle, albeit with modified constitution.

Intricate caged molecular frameworks are assembled by an atom economical process via a Diels-Alder (DA) reaction, a Claisen rearrangement, a ring-closing metathesis (RCM) and an alkenyl Grignard addition. The introduction of olefinic moieties in the pentacycloundecane (PCUD) framework at appropriate positions followed by RCM led to the formation of novel heptacyclic cage systems.