Propargyl vinyl ether Claisen substrate

The Claisen rearrangement of propargyl vinyl ethers directly delivers the allene no equilibrium is observed. This reaction was also successful with complex substrates in order to show this, of numerous examples [375, 513-536], the compounds 159 [537] and 161 [538] are depicted (Scheme 1.71). 

Dihydro-2-hydroxypyrans are formed from propargyl vinyl ethers in a Au(I)-catalysed Claisen rearrangement - heterocyclisation sequence in wet dioxane. Stereochemical features in the substrate are retained in the product. Incorporation of an alkanol function adjacent to the O atom results in the formation of spiroketals (Scheme 3) <06JA8132>. [3-Hydroxyallenes... 

Figure 11.14 Energy profile of the Rh-catalyzed Claisen rearrangement of propargyl vinyl ethers initiated by coordination at the alkyne. Red and gray depict the cis and the trans orientations, respectively, of CO relative to substrate at the Rh center. Energies were calculated relative to the most stable Rh(l)-vinyl ether complex at the M05-2X/LANL2DZ level.

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