Amino-Claisen rearrangement. III. The effects of alkyl substituents on the allyl group upon the rearrangement.

The effects of mono- and dimethylation of the allyl group upon tertiary and quaternary amino-Claisen rearrangements were investigated with 1, 2, 3, 4-tetrahydroquinoline as the framework for the rearrangement. The introduction of γ-methyl onto the allyl group accelerated the rearrangement and increased the yield of para rearrangement product. The introduction of two γ-methyls on the allyl group resulted in complex reactions, of which the major ones were para rearrangement and deprenylation. Two reaction pathways, sigmatropic and dissociative, were observed. The reaction conditions used strongly influenced the products pattern. The presence of a 6-methoxy group retarded the reaction but did not have a major effect upon the reaction pattern. Tertiary and quaternary N-Claisen rearrangements are effective for the migration of allyl and crotyl groups but seem not to be very useful for the migration of the prenyl group.