- Diastereoselective synthesis of 2,5-dimethylpyrrolidines and 2,6- dimethylpiperidines by reductive amination of 2,5-hexanedione and 2,6- heptanedione with hydride reagents
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The reductive amination of 2,5-hexanedione and 2,6-heptanedione with ammonia and primary amines in the presence of hydride reagents afforded 2,5- dimethylpyrrolidines and 2,6-dimethylpiperidines with variable diastereoselectivity, as the cis/trans ratio was affected by the size of the ring formed and the steric and electronic properties of the nitrogen substituent. Increasing the bulkiness of the nitrogen substituent, the cis pyrrolidines and the trans-piperidines were obtained with enhanced selectivity.
- Boga,Manescalchi,Savoia
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p. 4709 - 4722
(2007/10/02)
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- Synthesis of trans-2,6-Dialkylpiperidines by Intramolecular Amidomercuriation and by 1,3-Cycloaddition of Alkenes to 2-Methyl-2,3,4,5-tetrahydropyridine Oxide
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Intramolecular amidomercuriation of methyl N-hept-6-en-2-ylcarbamate and reaction of the resulting organomercurial with sodium borohydride in the presence of acrylonitrile or dec-1-en-3-one has been used to prepare trans-2,6-dialkylpiperidines.A more stereoselective route lies in the cycloaddition of alkenes to 2-alkyl-2,3,4,5-tetrahydropyridine oxides followed by reductive cleavage of the resulting perhydroisoxazolopyridine.Both procedures are illustrated by synthesis of the fire ant-venom alkaloid, solenopsin A.
- Adams, David R.,Carruthers, William,Williams, Michael J.,Crowley, Patrick J.
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p. 1507 - 1513
(2007/10/02)
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