Rearrangements in Five-Membered Heteroaromatic Rings

Claisen Rearrangements in Five-Membered Heteroaromatic Rings 

In the corresponding 2-S-allylindoles, rearrangement occurs as expected to give 3-allyl-2-thiooxindole derivatives even when the 3-position is already 

Claisen Rearrangements in Derivatives of Furfuryl Alcohol Analogues 

The corresponding rearrangement of substrates derived from furan-3-methanol is much more sluggish (70JCS(C)220). The intermediate vinyl ethers, for example 43, are easily isolated, and require a temperature of 160°C for rearrangement to occur (74JIC900). 

Finally, in the series of monocyclic azoles, 5-allyloxytetrazoles 44 undergo Claisen rearrangement on heating to 100-150°C to give the expected tetrazolones 45 (67JOC2956). 

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II. Claisen Rearrangements in Five-Membered Heteroaromatic Rings.20S... 

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