A Convenient Preparation of Diastereomerically Pure, Diversely Substituted Piperazine-2,5-diones from N-Protected α-Amino Acids
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Author(s)
Nikulnikov, Mikhail
Shumsky, Alexei
Krasavin, Mikhail
Griffith University Author(s)
Year published
2010
Metadata
Show full item recordAbstract
The products of the Ugi reaction of various N-tert-butoxycarbonyl-protected a-amino acids, aldehydes, amines and tert-butyl isocyanide, after tert-butoxycarbonyl deprotection, undergo efficient microwave-assisted cyclization in acetic acid to give diastereomerically pure, racemic piperazine-2,5-diones. The formation of a single diastereomer is rationalized via an enolization equilibration process in acetic acid at high temperature which enriches the product mixture in the more stable diastereomer. The relative stereochemistry of the products are confirmed by NOESY experiments and are consistent with molecular mechanics calculations.The products of the Ugi reaction of various N-tert-butoxycarbonyl-protected a-amino acids, aldehydes, amines and tert-butyl isocyanide, after tert-butoxycarbonyl deprotection, undergo efficient microwave-assisted cyclization in acetic acid to give diastereomerically pure, racemic piperazine-2,5-diones. The formation of a single diastereomer is rationalized via an enolization equilibration process in acetic acid at high temperature which enriches the product mixture in the more stable diastereomer. The relative stereochemistry of the products are confirmed by NOESY experiments and are consistent with molecular mechanics calculations.
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Journal Title
Synthesis
Volume
15
Copyright Statement
© 2010 Georg Thieme Verlag. This is the author-manuscript version of the paper. Reproduced in accordance with the copyright policy of the publisher. The definitive version is available at www.thieme-connect.com
Subject
Organic Chemical Synthesis
Analytical Chemistry
Organic Chemistry