Amino-Claisen rearrangement. V. Rearrangement of substituted tetrahydroquinolines involving competitive Cope rearrangement in a reaction intermediate.

A competitive Cope rearrangement was observed during Claisen rearrangement of substituted tetrahydroquinolines. It was found that the introduction of an ethyl group onto the methylene of the migrating allylic moiety greatly accelerated the Cope rearrangement. At the same time, replacement of the 1-ethyl-2-propenyl group on the aromatic ring by a 1-propenyl (allyl) group was observed.