Claisen rearrangements anionic oxy

Anionic oxy-Claisen rearrangement.2 The [3,3] Claisen rearrangement of en-olates of a-allyloxy ketones is markedly dependent on the nature of the metal hydride used, and to a less extent, the solvent. An example is the rearrangement of a-(allyloxy)propiophenone (1) to the a-hydroxy ketone 2. The rearrangement... 

In analogy with the oxy-Cope rearrangement, it has been called an anionic oxy-Claisen rearrangement. Like the anionic oxy-Cope reaction, this reaction shows a high sensitivity to the metal cation and solvent. The reaction rate is in the order K > Na > Li and THF > toluene. 

The enolate derived from 2-vinyl-6-acyldihydropyran S-c/i provides cyclooctadienone via anionic oxy-Claisen rearrangement (Scheme 11)7 ... 

The Cope, oxy-Cope, and anionic oxy-Cope rearrangements belong to the category of [3,3J-sigmatropic rearrangements. Since it is a concerted process, the arrow pushing here is only illustrative. Cf. Claisen rearrangement. 

C Anionic oxy-Cope rearrangement 4d Claisen rearrangement of allyl vinyl ethers... 

In this case, the ability to use a sulfide in place of a sulfoxide, with the oxidation-state adjustment and subsequent Mislow-Evans to occur later, provided a solution to the recalcitrant Claisen rearrangement. This strategy f Scheme 18.51) was particularly appealing in this case, because terminal thioethers are known to be strongly activating for [3,3]-sigmatropic anionic oxy-Cope rearrangements. ... 

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