- Amino-Claisen Rearrangement. III. The Effects of Alkyl Substituents on the Allyl Group upon the Rearrangement
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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 be very useful for the migration of the prenyl group; amino Claisen rearrangement; effect of alkyl substituent; ortho-, para-rearrangement; tropic rearrangement; dissociation-recombination mechanism
- Katayama, Hajime,Tachikawa, Yoshio,Takatsu, Noriyuki,Kato, Akira
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p. 2220 - 2233
(2007/10/02)
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- AMINO-CLAISEN REARRANGEMENT. II. QUATERNARY AMINO-CLAISEN REARRANGEMENT OF ANILINIUM COMPOUNDS WITH ORTHO SUBSTITUENTS
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Amino(N)-Claisen rearrangement of quaternary aniline derivatives with ortho substituents was investigated in relation to that of corresponding tertiary anilines.N-allylated anilinium compounds 1 with a freely rotating ortho substituent such as a methyl or methoxy group yielded mostly the deallylated products 4 along with minor amounts of rearrangement products 2 and 3.The corresponding tertiary anilines yielded ortho rearrangement products 6 together with para ones 7.The quaternary N-Claisen rearrangement of N-allylated 1,2,3,4-tetrahydroquinolinium salts 14 and indolinium salts 22 in which the ortho substituents are locked in rings afforded the ortho rearrangement products 15 and 23, respectively in good yields.N-Claisen rearrangement of the corresponding aromatic tertiary amines 18 also took place in good yield.The above rearrangements could be rationalized on the basis of mechanistic considerations.Keywords: - quaternary amino-Claisen rearrangement; mechanism; sigmatropic rearrangement; N-allyl-N,N-dimethyl-o-toluidinium bromide; N-allyl-N,N-dimethyl-o-anisidinium bromide; 1-allyl-1-methyl-1,2,3,4-tetrahydroquinolinium halides; 1-allyl-1,2-dimethylindolinium bromide; 8-allyl-1-methyl-1,2,3,4-tetrahydroquinoline; 6-allyl-1-methyl-1,2,3,4-tetrahydroquinoline; 7-allyl-1,2-dimethylindoline
- Katayama, Hajime,Takatsu, Noriyuki
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p. 2465 - 2477
(2007/10/02)
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