Iridium Catalyst Claisen rearrangement

An iridium(lll)-catalyzed tandem Claisen rearrangement-intramolecular hydroaryloxylation protocol has been described that allows the transformation of allyl aryl ethers to dihydrobenzofurans under mild conditions (Scheme 95) <2005TL1237>. An in rl/ -generated PPh3AuOTf complex also proved to be an efficient catalyst for this transformation <2006SL1278>. 

The cinnamyl ethers were treated with an iridium catalyst to furnish the corresponding vinyl ethers (Eq. 3.1.12). The utility of this catalyst was demonstrated in the stereoselective synthesis of aUyl vinyl ethers. 2,3,3-Trimethyl-4-pentenal was obtained in 51% yield when the isomerization of the diaUyl ether to give the aUyl vinyl ether was followed by heating to proceed the Claisen rearrangement (Eq. 3.1.13). 

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